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 //
   8 // Licensed under the terms of the GNU GPL
   9 //
  10 // (C) 2001 Ximian, Inc (http://www.ximian.com)
  11 //
  12 //
  13
  14 using System;
  15 using System.Collections;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18 using System.Text;
  19
  20 namespace Mono.CSharp {
  21
  22         /// <summary>
  23         ///   Holds Delegates
  24         /// </summary>
  25         public class Delegate : DeclSpace {
  26                 public Expression ReturnType;
  27                 public Parameters      Parameters;
  28
  29                 public ConstructorBuilder ConstructorBuilder;
  30                 public MethodBuilder      InvokeBuilder;
  31                 public MethodBuilder      BeginInvokeBuilder;
  32                 public MethodBuilder      EndInvokeBuilder;
  33
  34                 Type [] param_types;
  35                 Type ret_type;
  36
  37                 static string[] attribute_targets = new string [] { "type", "return" };
  38
  39                 Expression instance_expr;
  40                 MethodBase delegate_method;
  41                 ReturnParameter return_attributes;
  42
  43                 const int AllowedModifiers =
  44                         Modifiers.NEW |
  45                         Modifiers.PUBLIC |
  46                         Modifiers.PROTECTED |
  47                         Modifiers.INTERNAL |
  48                         Modifiers.UNSAFE |
  49                         Modifiers.PRIVATE;
  50
  51                 public Delegate (NamespaceEntry ns, TypeContainer parent, Expression type,
  52                                  int mod_flags, MemberName name, Parameters param_list,
  53                                  Attributes attrs, Location l)
  54                         : base (ns, parent, name, attrs, l)
  55
  56                 {
  57                         this.ReturnType = type;
  58                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  59                                                            IsTopLevel ? Modifiers.INTERNAL :
  60                                                            Modifiers.PRIVATE, l);
  61                         Parameters      = param_list;
  62                 }
  63
  64                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  65                 {
  66                         if (a.Target == AttributeTargets.ReturnValue) {
  67                                 if (return_attributes == null)
  68                                         return_attributes = new ReturnParameter (InvokeBuilder, Location);
  69
  70                                 return_attributes.ApplyAttributeBuilder (a, cb);
  71                                 return;
  72                         }
  73
  74                         base.ApplyAttributeBuilder (a, cb);
  75                 }
  76
  77                 public override TypeBuilder DefineType ()
  78                 {
  79                         if (TypeBuilder != null)
  80                                 return TypeBuilder;
  81
  82                         ec = new EmitContext (this, this, Location, null, null, ModFlags, false);
  83
  84                         TypeAttributes attr = Modifiers.TypeAttr (ModFlags, IsTopLevel) |
  85                                 TypeAttributes.Class | TypeAttributes.Sealed;
  86
  87                         if (TypeManager.multicast_delegate_type == null && !RootContext.StdLib) {
  88                                 TypeExpr expr = new TypeLookupExpression ("System.MulticastDelegate");
  89                                 TypeManager.multicast_delegate_type = expr.ResolveType (ec);
  90                         }
  91
  92                         if (TypeManager.multicast_delegate_type == null)
  93                                 throw new InternalErrorException ("System.MulticastDelegate unresolved");
  94
  95                         if (IsTopLevel) {
  96                                 if (TypeManager.NamespaceClash (Name, Location))
  97                                         return null;
  98
  99                                 ModuleBuilder builder = CodeGen.Module.Builder;
 100
 101                                 TypeBuilder = builder.DefineType (
 102                                         Name, attr, TypeManager.multicast_delegate_type);
 103                         } else {
 104                                 TypeBuilder builder = Parent.TypeBuilder;
 105
 106                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
 107                                 TypeBuilder = builder.DefineNestedType (
 108                                         name, attr, TypeManager.multicast_delegate_type);
 109                         }
 110
 111                         TypeManager.AddDelegateType (Name, TypeBuilder, this);
 112
 113                         return TypeBuilder;
 114                 }
 115
 116                 public override bool DefineMembers (TypeContainer container)
 117                 {
 118                         return true;
 119                 }
 120
 121                 public override bool Define ()
 122                 {
 123                         MethodAttributes mattr;
 124                         int i;
 125
 126                         if (ec == null)
 127                                 throw new InternalErrorException ("Define called before DefineType?");
 128
 129                         // FIXME: POSSIBLY make this static, as it is always constant
 130                         //
 131                         Type [] const_arg_types = new Type [2];
 132                         const_arg_types [0] = TypeManager.object_type;
 133                         const_arg_types [1] = TypeManager.intptr_type;
 134
 135                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 136                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 137
 138                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,
 139                                                                             CallingConventions.Standard,
 140                                                                             const_arg_types);
 141
 142                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 143                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 144                         //
 145                         // HACK because System.Reflection.Emit is lame
 146                         //
 147                         //
 148                         // FIXME: POSSIBLY make these static, as they are always the same
 149                         Parameter [] fixed_pars = new Parameter [2];
 150                         fixed_pars [0] = new Parameter (TypeManager.system_object_expr, "object",
 151                                                         Parameter.Modifier.NONE, null);
 152                         fixed_pars [1] = new Parameter (TypeManager.system_intptr_expr, "method",
 153                                                         Parameter.Modifier.NONE, null);
 154                         Parameters const_parameters = new Parameters (fixed_pars, null, Location);
 155
 156                         TypeManager.RegisterMethod (
 157                                 ConstructorBuilder,
 158                                 new InternalParameters (const_arg_types, const_parameters),
 159                                 const_arg_types);
 160
 161
 162                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 163
 164                         //
 165                         // Here the various methods like Invoke, BeginInvoke etc are defined
 166                         //
 167                         // First, call the `out of band' special method for
 168                         // defining recursively any types we need:
 169
 170                         param_types = Parameters.GetParameterInfo (ec);
 171                         if (param_types == null)
 172                                 return false;
 173
 174                         //
 175                         // Invoke method
 176                         //
 177
 178                         // Check accessibility
 179                         foreach (Type partype in param_types){
 180                                 if (!Parent.AsAccessible (partype, ModFlags)) {
 181                                         Report.Error (59, Location,
 182                                                       "Inconsistent accessibility: parameter type `" +
 183                                                       TypeManager.CSharpName (partype) + "` is less " +
 184                                                       "accessible than delegate `" + Name + "'");
 185                                         return false;
 186                                 }
 187                                 if (partype.IsPointer && !UnsafeOK (Parent))
 188                                         return false;
 189                         }
 190
 191                         ReturnType = ReturnType.ResolveAsTypeTerminal (ec, false);
 192                         if (ReturnType == null)
 193                             return false;
 194
 195                         ret_type = ReturnType.Type;
 196                         if (ret_type == null)
 197                                 return false;
 198
 199                         if (!Parent.AsAccessible (ret_type, ModFlags)) {
 200                                 Report.Error (58, Location,
 201                                               "Inconsistent accessibility: return type `" +
 202                                               TypeManager.CSharpName (ret_type) + "` is less " +
 203                                               "accessible than delegate `" + Name + "'");
 204                                 return false;
 205                         }
 206
 207                         if (ret_type.IsPointer && !UnsafeOK (Parent))
 208                                 return false;
 209
 210                         if (RootContext.StdLib && (ret_type == TypeManager.arg_iterator_type || ret_type == TypeManager.typed_reference_type)) {
 211                                 Method.Error1599 (Location, ret_type);
 212                                 return false;
 213                         }
 214
 215                         //
 216                         // We don't have to check any others because they are all
 217                         // guaranteed to be accessible - they are standard types.
 218                         //
 219
 220                         CallingConventions cc = Parameters.GetCallingConvention ();
 221
 222                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;
 223
 224                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 225                                                                   mattr,
 226                                                                   cc,
 227                                                                   ret_type,
 228                                                                   param_types);
 229
 230                         //
 231                         // Define parameters, and count out/ref parameters
 232                         //
 233                         int out_params = 0;
 234                         i = 0;
 235                         if (Parameters.FixedParameters != null){
 236                                 int top = Parameters.FixedParameters.Length;
 237                                 Parameter p;
 238
 239                                 for (; i < top; i++) {
 240                                         p = Parameters.FixedParameters [i];
 241                                         p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 242
 243                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 244                                                 out_params++;
 245                                 }
 246                         }
 247                         if (Parameters.ArrayParameter != null){
 248                                 Parameter p = Parameters.ArrayParameter;
 249                                 p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 250                         }
 251
 252                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 253
 254                         TypeManager.RegisterMethod (InvokeBuilder,
 255                                                     new InternalParameters (param_types, Parameters),
 256                                                     param_types);
 257
 258                         //
 259                         // BeginInvoke
 260                         //
 261                         int params_num = param_types.Length;
 262                         Type [] async_param_types = new Type [params_num + 2];
 263
 264                         param_types.CopyTo (async_param_types, 0);
 265
 266                         async_param_types [params_num] = TypeManager.asynccallback_type;
 267                         async_param_types [params_num + 1] = TypeManager.object_type;
 268
 269                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 270                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 271
 272                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 273                                                                        mattr,
 274                                                                        cc,
 275                                                                        TypeManager.iasyncresult_type,
 276                                                                        async_param_types);
 277
 278                         i = 0;
 279                         if (Parameters.FixedParameters != null){
 280                                 int top = Parameters.FixedParameters.Length;
 281                                 Parameter p;
 282
 283                                 for (i = 0 ; i < top; i++) {
 284                                         p = Parameters.FixedParameters [i];
 285
 286                                         p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 287                                 }
 288                         }
 289                         if (Parameters.ArrayParameter != null){
 290                                 Parameter p = Parameters.ArrayParameter;
 291                                 p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 292
 293                                 i++;
 294                         }
 295
 296                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 297                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 298
 299                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 300
 301                         Parameter [] async_params = new Parameter [params_num + 2];
 302                         int n = 0;
 303                         if (Parameters.FixedParameters != null){
 304                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 305                                 n = Parameters.FixedParameters.Length;
 306                         }
 307                         if (Parameters.ArrayParameter != null)
 308                                 async_params [n] = Parameters.ArrayParameter;
 309
 310                         async_params [params_num] = new Parameter (
 311                                 TypeManager.system_asynccallback_expr, "callback",
 312                                                                    Parameter.Modifier.NONE, null);
 313                         async_params [params_num + 1] = new Parameter (
 314                                 TypeManager.system_object_expr, "object",
 315                                                                    Parameter.Modifier.NONE, null);
 316
 317                         Parameters async_parameters = new Parameters (async_params, null, Location);
 318
 319                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 320                                                     new InternalParameters (async_parameters.GetParameterInfo (ec), async_parameters),
 321                                                     async_param_types);
 322
 323                         //
 324                         // EndInvoke is a bit more interesting, all the parameters labeled as
 325                         // out or ref have to be duplicated here.
 326                         //
 327
 328                         Type [] end_param_types = new Type [out_params + 1];
 329                         Parameter [] end_params = new Parameter [out_params + 1];
 330                         int param = 0;
 331                         if (out_params > 0){
 332                                 int top = Parameters.FixedParameters.Length;
 333                                 for (i = 0; i < top; i++){
 334                                         Parameter p = Parameters.FixedParameters [i];
 335                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 336                                                 continue;
 337
 338                                         end_param_types [param] = param_types [i];
 339                                         end_params [param] = p;
 340                                         param++;
 341                                 }
 342                         }
 343                         end_param_types [out_params] = TypeManager.iasyncresult_type;
 344                         end_params [out_params] = new Parameter (TypeManager.system_iasyncresult_expr, "result", Parameter.Modifier.NONE, null);
 345
 346                         //
 347                         // Create method, define parameters, register parameters with type system
 348                         //
 349                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_param_types);
 350                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 351
 352                         //
 353                         // EndInvoke: Label the parameters
 354                         //
 355                         EndInvokeBuilder.DefineParameter (out_params + 1, ParameterAttributes.None, "result");
 356                         for (i = 0; i < end_params.Length-1; i++){
 357                                 EndInvokeBuilder.DefineParameter (i + 1, end_params [i].Attributes, end_params [i].Name);
 358                         }
 359
 360                         Parameters end_parameters = new Parameters (end_params, null, Location);
 361
 362                         TypeManager.RegisterMethod (
 363                                 EndInvokeBuilder,
 364                                 new InternalParameters (end_parameters.GetParameterInfo (ec), end_parameters),
 365                                 end_param_types);
 366
 367                         return true;
 368                 }
 369
 370                 public override void Emit ()
 371                 {
 372                         if (OptAttributes != null) {
 373                                 Parameters.LabelParameters (ec, InvokeBuilder, Location);
 374                                 OptAttributes.Emit (ec, this);
 375                         }
 376
 377                         base.Emit ();
 378                 }
 379
 380                 public override string[] ValidAttributeTargets {
 381                         get {
 382                                 return attribute_targets;
 383                         }
 384                 }
 385
 386                 //TODO: duplicate
 387                 protected override bool VerifyClsCompliance (DeclSpace ds)
 388                 {
 389                         if (!base.VerifyClsCompliance (ds)) {
 390                                 return false;
 391                         }
 392
 393                         AttributeTester.AreParametersCompliant (Parameters.FixedParameters, Location);
 394
 395                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 396                                 Report.Error (3002, Location, "Return type of '{0}' is not CLS-compliant", GetSignatureForError ());
 397                         }
 398                         return true;
 399                 }
 400
 401                 //
 402                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 403                 // to extract the signature of a delegate.
 404                 //
 405                 public static MethodInfo GetInvokeMethod (EmitContext ec, Type delegate_type, Location loc)
 406                 {
 407                         Expression ml = Expression.MemberLookup (
 408                                 ec, delegate_type, "Invoke", loc);
 409
 410                         if (!(ml is MethodGroupExpr)) {
 411                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 412                                 return null;
 413                         }
 414
 415                         return (MethodInfo) (((MethodGroupExpr) ml).Methods [0]);
 416                 }
 417
 418                 /// <summary>
 419                 ///  Verifies whether the method in question is compatible with the delegate
 420                 ///  Returns the method itself if okay and null if not.
 421                 /// </summary>
 422                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,
 423                                                        Location loc)
 424                 {
 425                         ParameterData pd = TypeManager.GetParameterData (mb);
 426
 427                         int pd_count = pd.Count;
 428
 429                         MethodBase invoke_mb = GetInvokeMethod (ec, delegate_type, loc);
 430                         if (invoke_mb == null)
 431                                 return null;
 432
 433                         ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
 434
 435                         if (invoke_pd.Count != pd_count)
 436                                 return null;
 437
 438                         for (int i = pd_count; i > 0; ) {
 439                                 i--;
 440
 441                                 Type invoke_pd_type = invoke_pd.ParameterType (i);
 442                                 Type pd_type = pd.ParameterType (i);
 443                                 Parameter.Modifier invoke_pd_type_mod = invoke_pd.ParameterModifier (i);
 444                                 Parameter.Modifier pd_type_mod = pd.ParameterModifier (i);
 445
 446                                 if (invoke_pd_type == pd_type &&
 447                                     invoke_pd_type_mod == pd_type_mod)
 448                                         continue;
 449
 450                                 if (invoke_pd_type.IsSubclassOf (pd_type) &&
 451                                                 invoke_pd_type_mod == pd_type_mod)
 452                                         if (RootContext.Version == LanguageVersion.ISO_1) {
 453                                                 Report.FeatureIsNotStandardized (loc, "contravariance");
 454                                                 return null;
 455                                         } else
 456                                                 continue;
 457
 458                                 return null;
 459                         }
 460
 461                         Type invoke_mb_retval = ((MethodInfo) invoke_mb).ReturnType;
 462                         Type mb_retval = ((MethodInfo) mb).ReturnType;
 463                         if (invoke_mb_retval == mb_retval)
 464                                 return mb;
 465
 466                         if (mb_retval.IsSubclassOf (invoke_mb_retval))
 467                                 if (RootContext.Version == LanguageVersion.ISO_1) {
 468                                         Report.FeatureIsNotStandardized (loc, "covariance");
 469                                         return null;
 470                                 }
 471                                 else
 472                                         return mb;
 473
 474                         return null;
 475                 }
 476
 477                 // <summary>
 478                 //  Verifies whether the invocation arguments are compatible with the
 479                 //  delegate's target method
 480                 // </summary>
 481                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type,
 482                                                         ArrayList args, Location loc)
 483                 {
 484                         int arg_count;
 485
 486                         if (args == null)
 487                                 arg_count = 0;
 488                         else
 489                                 arg_count = args.Count;
 490
 491                         Expression ml = Expression.MemberLookup (
 492                                 ec, delegate_type, "Invoke", loc);
 493
 494                         MethodGroupExpr me = ml as MethodGroupExpr;
 495                         if (me == null) {
 496                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 497                                 return false;
 498                         }
 499
 500                         MethodBase mb = me.Methods [0];
 501                         ParameterData pd = TypeManager.GetParameterData (mb);
 502
 503                         int pd_count = pd.Count;
 504
 505                         bool params_method = (pd_count != 0) &&
 506                                 (pd.ParameterModifier (pd_count - 1) == Parameter.Modifier.PARAMS);
 507
 508                         bool is_params_applicable = false;
 509                         bool is_applicable = Invocation.IsApplicable (ec, me, args, arg_count, ref mb);
 510
 511                         if (!is_applicable && params_method &&
 512                             Invocation.IsParamsMethodApplicable (ec, me, args, arg_count, ref mb))
 513                                 is_applicable = is_params_applicable = true;
 514
 515                         if (!is_applicable && !params_method && arg_count != pd_count) {
 516                                 Report.Error (1593, loc,
 517                                               "Delegate '{0}' does not take {1} arguments",
 518                                               delegate_type.ToString (), arg_count);
 519                                 return false;
 520                         }
 521
 522                         return Invocation.VerifyArgumentsCompat (
 523                                         ec, args, arg_count, mb,
 524                                         is_params_applicable || (!is_applicable && params_method),
 525                                         delegate_type, false, loc);
 526                 }
 527
 528                 /// <summary>
 529                 ///  Verifies whether the delegate in question is compatible with this one in
 530                 ///  order to determine if instantiation from the same is possible.
 531                 /// </summary>
 532                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)
 533                 {
 534                         Expression ml = Expression.MemberLookup (
 535                                 ec, delegate_type, "Invoke", loc);
 536
 537                         if (!(ml is MethodGroupExpr)) {
 538                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 539                                 return false;
 540                         }
 541
 542                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 543                         ParameterData pd = TypeManager.GetParameterData (mb);
 544
 545                         Expression probe_ml = Expression.MemberLookup (
 546                                 ec, delegate_type, "Invoke", loc);
 547
 548                         if (!(probe_ml is MethodGroupExpr)) {
 549                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 550                                 return false;
 551                         }
 552
 553                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 554                         ParameterData probe_pd = TypeManager.GetParameterData (probe_mb);
 555
 556                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 557                                 return false;
 558
 559                         if (pd.Count != probe_pd.Count)
 560                                 return false;
 561
 562                         for (int i = pd.Count; i > 0; ) {
 563                                 i--;
 564
 565                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 566                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 567                                         return false;
 568                         }
 569
 570                         return true;
 571                 }
 572
 573                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 574                 {
 575                         StringBuilder sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 576
 577                         sb.Append (" " + del_type.ToString ());
 578                         sb.Append (" (");
 579
 580                         int length = pd.Count;
 581
 582                         for (int i = length; i > 0; ) {
 583                                 i--;
 584
 585                                 sb.Append (pd.ParameterDesc (length - i - 1));
 586                                 if (i != 0)
 587                                         sb.Append (", ");
 588                         }
 589
 590                         sb.Append (")");
 591                         return sb.ToString ();
 592
 593                 }
 594
 595                 // Hack around System.Reflection as found everywhere else
 596                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 597                                                         MemberFilter filter, object criteria)
 598                 {
 599                         ArrayList members = new ArrayList ();
 600
 601                         if ((mt & MemberTypes.Method) != 0) {
 602                                 if (ConstructorBuilder != null)
 603                                 if (filter (ConstructorBuilder, criteria))
 604                                         members.Add (ConstructorBuilder);
 605
 606                                 if (InvokeBuilder != null)
 607                                 if (filter (InvokeBuilder, criteria))
 608                                         members.Add (InvokeBuilder);
 609
 610                                 if (BeginInvokeBuilder != null)
 611                                 if (filter (BeginInvokeBuilder, criteria))
 612                                         members.Add (BeginInvokeBuilder);
 613
 614                                 if (EndInvokeBuilder != null)
 615                                 if (filter (EndInvokeBuilder, criteria))
 616                                         members.Add (EndInvokeBuilder);
 617                         }
 618
 619                         return new MemberList (members);
 620                 }
 621
 622                 public override MemberCache MemberCache {
 623                         get {
 624                                 return null;
 625                         }
 626                 }
 627
 628                 public Expression InstanceExpression {
 629                         get {
 630                                 return instance_expr;
 631                         }
 632                         set {
 633                                 instance_expr = value;
 634                         }
 635                 }
 636
 637                 public MethodBase TargetMethod {
 638                         get {
 639                                 return delegate_method;
 640                         }
 641                         set {
 642                                 delegate_method = value;
 643                         }
 644                 }
 645
 646                 public Type TargetReturnType {
 647                         get {
 648                                 return ret_type;
 649                         }
 650                 }
 651
 652                 public Type [] ParameterTypes {
 653                         get {
 654                                 return param_types;
 655                         }
 656                 }
 657
 658                 public override AttributeTargets AttributeTargets {
 659                         get {
 660                                 return AttributeTargets.Delegate;
 661                         }
 662                 }
 663
 664                 //
 665                 //   Represents header string for documentation comment.
 666                 //
 667                 public override string DocCommentHeader {
 668                         get { return "T:"; }
 669                 }
 670
 671                 protected override void VerifyObsoleteAttribute()
 672                 {
 673                         CheckUsageOfObsoleteAttribute (ret_type);
 674
 675                         foreach (Type type in param_types) {
 676                                 CheckUsageOfObsoleteAttribute (type);
 677                         }
 678                 }
 679         }
 680
 681         //
 682         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 683         //
 684         public abstract class DelegateCreation : Expression {
 685                 protected MethodBase constructor_method;
 686                 protected MethodBase delegate_method;
 687                 protected MethodGroupExpr method_group;
 688                 protected Expression delegate_instance_expression;
 689
 690                 public DelegateCreation () {}
 691
 692                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 693                 {
 694                         string method_desc;
 695                         MethodInfo found_method = (MethodInfo)mg.Methods [0];
 696
 697                         if (mg.Methods.Length > 1)
 698                                 method_desc = found_method.Name;
 699                         else
 700                                 method_desc = Invocation.FullMethodDesc (found_method);
 701
 702                         Expression invoke_method = Expression.MemberLookup (
 703                                 ec, type, "Invoke", MemberTypes.Method,
 704                                 Expression.AllBindingFlags, loc);
 705                         MethodInfo method = ((MethodGroupExpr) invoke_method).Methods [0] as MethodInfo;
 706
 707                         ParameterData param = TypeManager.GetParameterData (method);
 708                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 709
 710                         if (method.ReturnType != found_method.ReturnType) {
 711                                 Report.Error (407, loc, "'{0}' has the wrong return type to match delegate '{1}'", method_desc, delegate_desc);
 712                         } else {
 713                                 Report.Error (123, loc, "Method '" + method_desc + "' does not " +
 714                                         "match delegate '" + delegate_desc + "'");
 715                         }
 716                 }
 717
 718                 public override void Emit (EmitContext ec)
 719                 {
 720                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 721                                 ec.ig.Emit (OpCodes.Ldnull);
 722                         else
 723                                 delegate_instance_expression.Emit (ec);
 724
 725                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 726                                 ec.ig.Emit (OpCodes.Dup);
 727                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 728                         } else
 729                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 730                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 731                 }
 732
 733                 protected bool ResolveConstructorMethod (EmitContext ec)
 734                 {
 735                         Expression ml = Expression.MemberLookup (
 736                                 ec, type, ".ctor", loc);
 737
 738                         if (!(ml is MethodGroupExpr)) {
 739                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 740                                 return false;
 741                         }
 742
 743                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 744                         return true;
 745                 }
 746
 747                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg)
 748                 {
 749                         foreach (MethodInfo mi in mg.Methods){
 750                                 delegate_method  = Delegate.VerifyMethod (ec, type, mi, loc);
 751
 752                                 if (delegate_method != null)
 753                                         break;
 754                         }
 755
 756                         if (delegate_method == null) {
 757                                 Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 758                                 return null;
 759                         }
 760
 761                         //
 762                         // Check safe/unsafe of the delegate
 763                         //
 764                         if (!ec.InUnsafe){
 765                                 ParameterData param = TypeManager.GetParameterData (delegate_method);
 766                                 int count = param.Count;
 767
 768                                 for (int i = 0; i < count; i++){
 769                                         if (param.ParameterType (i).IsPointer){
 770                                                 Expression.UnsafeError (loc);
 771                                                 return null;
 772                                         }
 773                                 }
 774                         }
 775
 776                         //TODO: implement caching when performance will be low
 777                         IMethodData md = TypeManager.GetMethod (delegate_method);
 778                         if (md == null) {
 779                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 780                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 781                                 }
 782                         } else {
 783                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type, ec) != null) {
 784                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 785                                 }
 786                         }
 787
 788                         if (mg.InstanceExpression != null)
 789                                 delegate_instance_expression = mg.InstanceExpression.Resolve (ec);
 790                         else if (ec.IsStatic) {
 791                                 if (!delegate_method.IsStatic) {
 792                                         Report.Error (120, loc,
 793                                                       "An object reference is required for the non-static method " +
 794                                                       delegate_method.Name);
 795                                         return null;
 796                                 }
 797                                 delegate_instance_expression = null;
 798                         } else
 799                                 delegate_instance_expression = ec.GetThis (loc);
 800
 801                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 802                                 delegate_instance_expression = new BoxedCast (delegate_instance_expression);
 803
 804                         method_group = mg;
 805                         eclass = ExprClass.Value;
 806                         return this;
 807                 }
 808         }
 809
 810         //
 811         // Created from the conversion code
 812         //
 813         public class ImplicitDelegateCreation : DelegateCreation {
 814
 815                 ImplicitDelegateCreation (Type t, Location l)
 816                 {
 817                         type = t;
 818                         loc = l;
 819                 }
 820
 821                 public override Expression DoResolve (EmitContext ec)
 822                 {
 823                         return this;
 824                 }
 825
 826                 static public Expression Create (EmitContext ec, MethodGroupExpr mge, Type target_type, Location loc)
 827                 {
 828                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 829                         if (d.ResolveConstructorMethod (ec))
 830                                 return d.ResolveMethodGroupExpr (ec, mge);
 831                         else
 832                                 return null;
 833                 }
 834         }
 835
 836         //
 837         // A delegate-creation-expression, invoked from the `New' class
 838         //
 839         public class NewDelegate : DelegateCreation {
 840                 public ArrayList Arguments;
 841
 842                 //
 843                 // This constructor is invoked from the `New' expression
 844                 //
 845                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 846                 {
 847                         this.type = type;
 848                         this.Arguments = Arguments;
 849                         this.loc  = loc;
 850                 }
 851
 852                 public override Expression DoResolve (EmitContext ec)
 853                 {
 854                         if (Arguments == null || Arguments.Count != 1) {
 855                                 Report.Error (149, loc,
 856                                               "Method name expected");
 857                                 return null;
 858                         }
 859
 860                         if (!ResolveConstructorMethod (ec))
 861                                 return null;
 862
 863                         Argument a = (Argument) Arguments [0];
 864
 865                         if (!a.ResolveMethodGroup (ec, loc))
 866                                 return null;
 867
 868                         Expression e = a.Expr;
 869
 870                         if (e is AnonymousMethod && RootContext.Version != LanguageVersion.ISO_1)
 871                                 return ((AnonymousMethod) e).Compatible (ec, type, false);
 872
 873                         MethodGroupExpr mg = e as MethodGroupExpr;
 874                         if (mg != null)
 875                                 return ResolveMethodGroupExpr (ec, mg);
 876
 877                         Type e_type = e.Type;
 878
 879                         if (!TypeManager.IsDelegateType (e_type)) {
 880                                 Report.Error (149, loc, "Method name expected");
 881                                 return null;
 882                         }
 883
 884                         method_group = Expression.MemberLookup (
 885                                 ec, type, "Invoke", MemberTypes.Method,
 886                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 887
 888                         if (method_group == null) {
 889                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 890                                 return null;
 891                         }
 892
 893                         // This is what MS' compiler reports. We could always choose
 894                         // to be more verbose and actually give delegate-level specifics
 895                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 896                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 897                                               "to type '" + type + "'");
 898                                 return null;
 899                         }
 900
 901                         delegate_instance_expression = e;
 902                         delegate_method = method_group.Methods [0];
 903
 904                         eclass = ExprClass.Value;
 905                         return this;
 906                 }
 907         }
 908
 909         public class DelegateInvocation : ExpressionStatement {
 910
 911                 public Expression InstanceExpr;
 912                 public ArrayList  Arguments;
 913
 914                 MethodBase method;
 915
 916                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 917                 {
 918                         this.InstanceExpr = instance_expr;
 919                         this.Arguments = args;
 920                         this.loc = loc;
 921                 }
 922
 923                 public override Expression DoResolve (EmitContext ec)
 924                 {
 925                         if (InstanceExpr is EventExpr) {
 926
 927                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 928
 929                                 Expression ml = MemberLookup (
 930                                         ec, ec.ContainerType, ei.Name,
 931                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 932
 933                                 if (ml == null) {
 934                                         //
 935                                         // If this is the case, then the Event does not belong
 936                                         // to this Type and so, according to the spec
 937                                         // cannot be accessed directly
 938                                         //
 939                                         // Note that target will not appear as an EventExpr
 940                                         // in the case it is being referenced within the same type container;
 941                                         // it will appear as a FieldExpr in that case.
 942                                         //
 943
 944                                         Assign.error70 (ei, loc);
 945                                         return null;
 946                                 }
 947                         }
 948
 949
 950                         Type del_type = InstanceExpr.Type;
 951                         if (del_type == null)
 952                                 return null;
 953
 954                         if (Arguments != null){
 955                                 foreach (Argument a in Arguments){
 956                                         if (!a.Resolve (ec, loc))
 957                                                 return null;
 958                                 }
 959                         }
 960
 961                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
 962                                 return null;
 963
 964                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
 965                         if (!(lookup is MethodGroupExpr)) {
 966                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 967                                 return null;
 968                         }
 969
 970                         method = ((MethodGroupExpr) lookup).Methods [0];
 971                         type = ((MethodInfo) method).ReturnType;
 972                         eclass = ExprClass.Value;
 973
 974                         return this;
 975                 }
 976
 977                 public override void Emit (EmitContext ec)
 978                 {
 979                         //
 980                         // Invocation on delegates call the virtual Invoke member
 981                         // so we are always `instance' calls
 982                         //
 983                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
 984                 }
 985
 986                 public override void EmitStatement (EmitContext ec)
 987                 {
 988                         Emit (ec);
 989                         //
 990                         // Pop the return value if there is one
 991                         //
 992                         if (method is MethodInfo){
 993                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
 994                                         ec.ig.Emit (OpCodes.Pop);
 995                         }
 996                 }
 997
 998         }
 999 }