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                         TypeAttributes attr = Modifiers.TypeAttr (ModFlags, IsTopLevel) |
  83                                 TypeAttributes.Class | TypeAttributes.Sealed;
  84
  85                         if (IsTopLevel) {
  86                                 if (TypeManager.NamespaceClash (Name, Location))
  87                                         return null;
  88
  89                                 ModuleBuilder builder = CodeGen.Module.Builder;
  90
  91                                 TypeBuilder = builder.DefineType (
  92                                         Name, attr, TypeManager.multicast_delegate_type);
  93                         } else {
  94                                 TypeBuilder builder = Parent.TypeBuilder;
  95
  96                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
  97                                 TypeBuilder = builder.DefineNestedType (
  98                                         name, attr, TypeManager.multicast_delegate_type);
  99                         }
 100
 101                         TypeManager.AddDelegateType (Name, TypeBuilder, this);
 102
 103                         return TypeBuilder;
 104                 }
 105
 106                 public override bool DefineMembers (TypeContainer container)
 107                 {
 108                         return true;
 109                 }
 110
 111                 public override bool Define ()
 112                 {
 113                         MethodAttributes mattr;
 114                         int i;
 115                         EmitContext ec = new EmitContext (this, this, Location, null,
 116                                                           null, ModFlags, false);
 117
 118                         // FIXME: POSSIBLY make this static, as it is always constant
 119                         //
 120                         Type [] const_arg_types = new Type [2];
 121                         const_arg_types [0] = TypeManager.object_type;
 122                         const_arg_types [1] = TypeManager.intptr_type;
 123
 124                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 125                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 126
 127                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,
 128                                                                             CallingConventions.Standard,
 129                                                                             const_arg_types);
 130
 131                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 132                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 133                         //
 134                         // HACK because System.Reflection.Emit is lame
 135                         //
 136                         //
 137                         // FIXME: POSSIBLY make these static, as they are always the same
 138                         Parameter [] fixed_pars = new Parameter [2];
 139                         fixed_pars [0] = new Parameter (TypeManager.system_object_expr, "object",
 140                                                         Parameter.Modifier.NONE, null);
 141                         fixed_pars [1] = new Parameter (TypeManager.system_intptr_expr, "method",
 142                                                         Parameter.Modifier.NONE, null);
 143                         Parameters const_parameters = new Parameters (fixed_pars, null, Location);
 144
 145                         TypeManager.RegisterMethod (
 146                                 ConstructorBuilder,
 147                                 new InternalParameters (const_arg_types, const_parameters),
 148                                 const_arg_types);
 149
 150
 151                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 152
 153                         //
 154                         // Here the various methods like Invoke, BeginInvoke etc are defined
 155                         //
 156                         // First, call the `out of band' special method for
 157                         // defining recursively any types we need:
 158
 159                         if (!Parameters.ComputeAndDefineParameterTypes (ec))
 160                                 return false;
 161
 162                         param_types = Parameters.GetParameterInfo (ec);
 163                         if (param_types == null)
 164                                 return false;
 165
 166                         //
 167                         // Invoke method
 168                         //
 169
 170                         // Check accessibility
 171                         foreach (Type partype in param_types){
 172                                 if (!Parent.AsAccessible (partype, ModFlags)) {
 173                                         Report.Error (59, Location,
 174                                                       "Inconsistent accessibility: parameter type `" +
 175                                                       TypeManager.CSharpName (partype) + "` is less " +
 176                                                       "accessible than delegate `" + Name + "'");
 177                                         return false;
 178                                 }
 179                                 if (partype.IsPointer && !UnsafeOK (Parent))
 180                                         return false;
 181                         }
 182
 183                         ReturnType = ReturnType.ResolveAsTypeTerminal (ec, false);
 184                         if (ReturnType == null)
 185                             return false;
 186
 187                         ret_type = ReturnType.Type;
 188                         if (ret_type == null)
 189                                 return false;
 190
 191                         if (!Parent.AsAccessible (ret_type, ModFlags)) {
 192                                 Report.Error (58, Location,
 193                                               "Inconsistent accessibility: return type `" +
 194                                               TypeManager.CSharpName (ret_type) + "` is less " +
 195                                               "accessible than delegate `" + Name + "'");
 196                                 return false;
 197                         }
 198
 199                         if (ret_type.IsPointer && !UnsafeOK (Parent))
 200                                 return false;
 201
 202                         //
 203                         // We don't have to check any others because they are all
 204                         // guaranteed to be accessible - they are standard types.
 205                         //
 206
 207                         CallingConventions cc = Parameters.GetCallingConvention ();
 208
 209                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;
 210
 211                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 212                                                                   mattr,
 213                                                                   cc,
 214                                                                   ret_type,
 215                                                                   param_types);
 216
 217                         //
 218                         // Define parameters, and count out/ref parameters
 219                         //
 220                         int out_params = 0;
 221                         i = 0;
 222                         if (Parameters.FixedParameters != null){
 223                                 int top = Parameters.FixedParameters.Length;
 224                                 Parameter p;
 225
 226                                 for (; i < top; i++) {
 227                                         p = Parameters.FixedParameters [i];
 228                                         p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 229
 230                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 231                                                 out_params++;
 232                                 }
 233                         }
 234                         if (Parameters.ArrayParameter != null){
 235                                 Parameter p = Parameters.ArrayParameter;
 236                                 p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 237                         }
 238
 239                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 240
 241                         TypeManager.RegisterMethod (InvokeBuilder,
 242                                                     new InternalParameters (param_types, Parameters),
 243                                                     param_types);
 244
 245                         //
 246                         // BeginInvoke
 247                         //
 248                         int params_num = param_types.Length;
 249                         Type [] async_param_types = new Type [params_num + 2];
 250
 251                         param_types.CopyTo (async_param_types, 0);
 252
 253                         async_param_types [params_num] = TypeManager.asynccallback_type;
 254                         async_param_types [params_num + 1] = TypeManager.object_type;
 255
 256                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 257                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 258
 259                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 260                                                                        mattr,
 261                                                                        cc,
 262                                                                        TypeManager.iasyncresult_type,
 263                                                                        async_param_types);
 264
 265                         i = 0;
 266                         if (Parameters.FixedParameters != null){
 267                                 int top = Parameters.FixedParameters.Length;
 268                                 Parameter p;
 269
 270                                 for (i = 0 ; i < top; i++) {
 271                                         p = Parameters.FixedParameters [i];
 272
 273                                         p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 274                                 }
 275                         }
 276                         if (Parameters.ArrayParameter != null){
 277                                 Parameter p = Parameters.ArrayParameter;
 278                                 p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 279
 280                                 i++;
 281                         }
 282
 283                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 284                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 285
 286                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 287
 288                         Parameter [] async_params = new Parameter [params_num + 2];
 289                         int n = 0;
 290                         if (Parameters.FixedParameters != null){
 291                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 292                                 n = Parameters.FixedParameters.Length;
 293                         }
 294                         if (Parameters.ArrayParameter != null)
 295                                 async_params [n] = Parameters.ArrayParameter;
 296
 297                         async_params [params_num] = new Parameter (
 298                                 TypeManager.system_asynccallback_expr, "callback",
 299                                                                    Parameter.Modifier.NONE, null);
 300                         async_params [params_num + 1] = new Parameter (
 301                                 TypeManager.system_object_expr, "object",
 302                                                                    Parameter.Modifier.NONE, null);
 303
 304                         Parameters async_parameters = new Parameters (async_params, null, Location);
 305                         async_parameters.ComputeAndDefineParameterTypes (ec);
 306
 307                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 308                                                     new InternalParameters (async_param_types, async_parameters),
 309                                                     async_param_types);
 310
 311                         //
 312                         // EndInvoke is a bit more interesting, all the parameters labeled as
 313                         // out or ref have to be duplicated here.
 314                         //
 315
 316                         Type [] end_param_types = new Type [out_params + 1];
 317                         Parameter [] end_params = new Parameter [out_params + 1];
 318                         int param = 0;
 319                         if (out_params > 0){
 320                                 int top = Parameters.FixedParameters.Length;
 321                                 for (i = 0; i < top; i++){
 322                                         Parameter p = Parameters.FixedParameters [i];
 323                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 324                                                 continue;
 325
 326                                         end_param_types [param] = param_types [i];
 327                                         end_params [param] = p;
 328                                         param++;
 329                                 }
 330                         }
 331                         end_param_types [out_params] = TypeManager.iasyncresult_type;
 332                         end_params [out_params] = new Parameter (TypeManager.system_iasyncresult_expr, "result", Parameter.Modifier.NONE, null);
 333
 334                         //
 335                         // Create method, define parameters, register parameters with type system
 336                         //
 337                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_param_types);
 338                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 339
 340                         //
 341                         // EndInvoke: Label the parameters
 342                         //
 343                         EndInvokeBuilder.DefineParameter (out_params + 1, ParameterAttributes.None, "result");
 344                         for (i = 0; i < end_params.Length-1; i++){
 345                                 EndInvokeBuilder.DefineParameter (i + 1, end_params [i].Attributes, end_params [i].Name);
 346                         }
 347
 348                         Parameters end_parameters = new Parameters (end_params, null, Location);
 349                         end_parameters.ComputeAndDefineParameterTypes (ec);
 350
 351                         TypeManager.RegisterMethod (
 352                                 EndInvokeBuilder,
 353                                 new InternalParameters (end_param_types, end_parameters),
 354                                 end_param_types);
 355
 356                         return true;
 357                 }
 358
 359                 public override void Emit ()
 360                 {
 361                         if (OptAttributes != null) {
 362                                 EmitContext ec = new EmitContext (
 363                                         Parent, this, Location, null, null, ModFlags, false);
 364                                 Parameters.LabelParameters (ec, InvokeBuilder, Location);
 365                                 OptAttributes.Emit (ec, this);
 366                         }
 367
 368                         base.Emit ();
 369                 }
 370
 371                 public override string[] ValidAttributeTargets {
 372                         get {
 373                                 return attribute_targets;
 374                         }
 375                 }
 376
 377                 //TODO: duplicate
 378                 protected override bool VerifyClsCompliance (DeclSpace ds)
 379                 {
 380                         if (!base.VerifyClsCompliance (ds)) {
 381                                 return false;
 382                         }
 383
 384                         AttributeTester.AreParametersCompliant (Parameters.FixedParameters, Location);
 385
 386                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 387                                 Report.Error (3002, Location, "Return type of '{0}' is not CLS-compliant", GetSignatureForError ());
 388                         }
 389                         return true;
 390                 }
 391
 392                 //
 393                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 394                 // to extract the signature of a delegate.
 395                 //
 396                 public static MethodInfo GetInvokeMethod (EmitContext ec, Type delegate_type, Location loc)
 397                 {
 398                         Expression ml = Expression.MemberLookup (
 399                                 ec, delegate_type, "Invoke", loc);
 400
 401                         if (!(ml is MethodGroupExpr)) {
 402                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 403                                 return null;
 404                         }
 405
 406                         return (MethodInfo) (((MethodGroupExpr) ml).Methods [0]);
 407                 }
 408
 409                 /// <summary>
 410                 ///  Verifies whether the method in question is compatible with the delegate
 411                 ///  Returns the method itself if okay and null if not.
 412                 /// </summary>
 413                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,
 414                                                        Location loc)
 415                 {
 416                         ParameterData pd = Invocation.GetParameterData (mb);
 417
 418                         int pd_count = pd.Count;
 419
 420                         MethodBase invoke_mb = GetInvokeMethod (ec, delegate_type, loc);
 421                         if (invoke_mb == null)
 422                                 return null;
 423
 424                         ParameterData invoke_pd = Invocation.GetParameterData (invoke_mb);
 425
 426                         if (invoke_pd.Count != pd_count)
 427                                 return null;
 428
 429                         for (int i = pd_count; i > 0; ) {
 430                                 i--;
 431
 432                                 if (invoke_pd.ParameterType (i) == pd.ParameterType (i) &&
 433                                     invoke_pd.ParameterModifier (i) == pd.ParameterModifier (i))
 434                                         continue;
 435                                 else {
 436                                         return null;
 437                                 }
 438                         }
 439
 440                         if (((MethodInfo) invoke_mb).ReturnType == ((MethodInfo) mb).ReturnType)
 441                                 return mb;
 442                         else
 443                                 return null;
 444                 }
 445
 446                 // <summary>
 447                 //  Verifies whether the invocation arguments are compatible with the
 448                 //  delegate's target method
 449                 // </summary>
 450                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type,
 451                                                         ArrayList args, Location loc)
 452                 {
 453                         int arg_count;
 454
 455                         if (args == null)
 456                                 arg_count = 0;
 457                         else
 458                                 arg_count = args.Count;
 459
 460                         Expression ml = Expression.MemberLookup (
 461                                 ec, delegate_type, "Invoke", loc);
 462
 463                         if (!(ml is MethodGroupExpr)) {
 464                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 465                                 return false;
 466                         }
 467
 468                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 469                         ParameterData pd = Invocation.GetParameterData (mb);
 470
 471                         int pd_count = pd.Count;
 472
 473                         bool params_method = (pd_count != 0) &&
 474                                 (pd.ParameterModifier (pd_count - 1) == Parameter.Modifier.PARAMS);
 475
 476                         if (!params_method && pd_count != arg_count) {
 477                                 Report.Error (1593, loc,
 478                                               "Delegate '{0}' does not take {1} arguments",
 479                                               delegate_type.ToString (), arg_count);
 480                                 return false;
 481                         }
 482
 483                         //
 484                         // Consider the case:
 485                         //   delegate void FOO(param object[] args);
 486                         //   FOO f = new FOO(...);
 487                         //   f(new object[] {1, 2, 3});
 488                         //
 489                         // This should be treated like f(1,2,3).  This is done by ignoring the
 490                         // 'param' modifier for that invocation.  If that fails, then the
 491                         // 'param' modifier is considered.
 492                         //
 493                         // One issue is that 'VerifyArgumentsCompat' modifies the elements of
 494                         // the 'args' array.  However, the modifications appear idempotent.
 495                         // Normal 'Invocation's also have the same behaviour, implicitly.
 496                         //
 497
 498                         bool ans = false;
 499                         if (arg_count == pd_count)
 500                                 ans = Invocation.VerifyArgumentsCompat (
 501                                         ec, args, arg_count, mb, false,
 502                                         delegate_type, false, loc);
 503                         if (!ans && params_method)
 504                                 ans = Invocation.VerifyArgumentsCompat (
 505                                         ec, args, arg_count, mb, true,
 506                                         delegate_type, false, loc);
 507                         return ans;
 508                 }
 509
 510                 /// <summary>
 511                 ///  Verifies whether the delegate in question is compatible with this one in
 512                 ///  order to determine if instantiation from the same is possible.
 513                 /// </summary>
 514                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)
 515                 {
 516                         Expression ml = Expression.MemberLookup (
 517                                 ec, delegate_type, "Invoke", loc);
 518
 519                         if (!(ml is MethodGroupExpr)) {
 520                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 521                                 return false;
 522                         }
 523
 524                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 525                         ParameterData pd = Invocation.GetParameterData (mb);
 526
 527                         Expression probe_ml = Expression.MemberLookup (
 528                                 ec, delegate_type, "Invoke", loc);
 529
 530                         if (!(probe_ml is MethodGroupExpr)) {
 531                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 532                                 return false;
 533                         }
 534
 535                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 536                         ParameterData probe_pd = Invocation.GetParameterData (probe_mb);
 537
 538                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 539                                 return false;
 540
 541                         if (pd.Count != probe_pd.Count)
 542                                 return false;
 543
 544                         for (int i = pd.Count; i > 0; ) {
 545                                 i--;
 546
 547                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 548                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 549                                         return false;
 550                         }
 551
 552                         return true;
 553                 }
 554
 555                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 556                 {
 557                         StringBuilder sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 558
 559                         sb.Append (" " + del_type.ToString ());
 560                         sb.Append (" (");
 561
 562                         int length = pd.Count;
 563
 564                         for (int i = length; i > 0; ) {
 565                                 i--;
 566
 567                                 sb.Append (pd.ParameterDesc (length - i - 1));
 568                                 if (i != 0)
 569                                         sb.Append (", ");
 570                         }
 571
 572                         sb.Append (")");
 573                         return sb.ToString ();
 574
 575                 }
 576
 577                 // Hack around System.Reflection as found everywhere else
 578                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 579                                                         MemberFilter filter, object criteria)
 580                 {
 581                         ArrayList members = new ArrayList ();
 582
 583                         if ((mt & MemberTypes.Method) != 0) {
 584                                 if (ConstructorBuilder != null)
 585                                 if (filter (ConstructorBuilder, criteria))
 586                                         members.Add (ConstructorBuilder);
 587
 588                                 if (InvokeBuilder != null)
 589                                 if (filter (InvokeBuilder, criteria))
 590                                         members.Add (InvokeBuilder);
 591
 592                                 if (BeginInvokeBuilder != null)
 593                                 if (filter (BeginInvokeBuilder, criteria))
 594                                         members.Add (BeginInvokeBuilder);
 595
 596                                 if (EndInvokeBuilder != null)
 597                                 if (filter (EndInvokeBuilder, criteria))
 598                                         members.Add (EndInvokeBuilder);
 599                         }
 600
 601                         return new MemberList (members);
 602                 }
 603
 604                 public override MemberCache MemberCache {
 605                         get {
 606                                 return null;
 607                         }
 608                 }
 609
 610                 public Expression InstanceExpression {
 611                         get {
 612                                 return instance_expr;
 613                         }
 614                         set {
 615                                 instance_expr = value;
 616                         }
 617                 }
 618
 619                 public MethodBase TargetMethod {
 620                         get {
 621                                 return delegate_method;
 622                         }
 623                         set {
 624                                 delegate_method = value;
 625                         }
 626                 }
 627
 628                 public Type TargetReturnType {
 629                         get {
 630                                 return ret_type;
 631                         }
 632                 }
 633
 634                 public Type [] ParameterTypes {
 635                         get {
 636                                 return param_types;
 637                         }
 638                 }
 639
 640                 public override AttributeTargets AttributeTargets {
 641                         get {
 642                                 return AttributeTargets.Delegate;
 643                         }
 644                 }
 645
 646                 protected override void VerifyObsoleteAttribute()
 647                 {
 648                         CheckUsageOfObsoleteAttribute (ret_type);
 649
 650                         foreach (Type type in param_types) {
 651                                 CheckUsageOfObsoleteAttribute (type);
 652                         }
 653                 }
 654         }
 655
 656         //
 657         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 658         //
 659         public abstract class DelegateCreation : Expression {
 660                 protected MethodBase constructor_method;
 661                 protected MethodBase delegate_method;
 662                 protected MethodGroupExpr method_group;
 663                 protected Expression delegate_instance_expression;
 664
 665                 public DelegateCreation () {}
 666
 667                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 668                 {
 669                         string method_desc;
 670
 671                         if (mg.Methods.Length > 1)
 672                                 method_desc = mg.Methods [0].Name;
 673                         else
 674                                 method_desc = Invocation.FullMethodDesc (mg.Methods [0]);
 675
 676                         Expression invoke_method = Expression.MemberLookup (
 677                                 ec, type, "Invoke", MemberTypes.Method,
 678                                 Expression.AllBindingFlags, loc);
 679                         MethodBase method = ((MethodGroupExpr) invoke_method).Methods [0];
 680                         ParameterData param = Invocation.GetParameterData (method);
 681                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 682
 683                         Report.Error (123, loc, "Method '" + method_desc + "' does not " +
 684                                       "match delegate '" + delegate_desc + "'");
 685                 }
 686
 687                 public override void Emit (EmitContext ec)
 688                 {
 689                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 690                                 ec.ig.Emit (OpCodes.Ldnull);
 691                         else
 692                                 delegate_instance_expression.Emit (ec);
 693
 694                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 695                                 ec.ig.Emit (OpCodes.Dup);
 696                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 697                         } else
 698                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 699                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 700                 }
 701
 702                 protected bool ResolveConstructorMethod (EmitContext ec)
 703                 {
 704                         Expression ml = Expression.MemberLookup (
 705                                 ec, type, ".ctor", loc);
 706
 707                         if (!(ml is MethodGroupExpr)) {
 708                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 709                                 return false;
 710                         }
 711
 712                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 713                         return true;
 714                 }
 715
 716                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg)
 717                 {
 718                         foreach (MethodInfo mi in mg.Methods){
 719                                 delegate_method  = Delegate.VerifyMethod (ec, type, mi, loc);
 720
 721                                 if (delegate_method != null)
 722                                         break;
 723                         }
 724
 725                         if (delegate_method == null) {
 726                                 Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 727                                 return null;
 728                         }
 729
 730                         //
 731                         // Check safe/unsafe of the delegate
 732                         //
 733                         if (!ec.InUnsafe){
 734                                 ParameterData param = Invocation.GetParameterData (delegate_method);
 735                                 int count = param.Count;
 736
 737                                 for (int i = 0; i < count; i++){
 738                                         if (param.ParameterType (i).IsPointer){
 739                                                 Expression.UnsafeError (loc);
 740                                                 return null;
 741                                         }
 742                                 }
 743                         }
 744
 745                         //TODO: implement caching when performance will be low
 746                         IMethodData md = TypeManager.GetMethod (delegate_method);
 747                         if (md == null) {
 748                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 749                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 750                                 }
 751                         } else {
 752                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type, ec) != null) {
 753                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 754                                 }
 755                         }
 756
 757                         if (mg.InstanceExpression != null)
 758                                 delegate_instance_expression = mg.InstanceExpression.Resolve (ec);
 759                         else if (ec.IsStatic) {
 760                                 if (!delegate_method.IsStatic) {
 761                                         Report.Error (120, loc,
 762                                                       "An object reference is required for the non-static method " +
 763                                                       delegate_method.Name);
 764                                         return null;
 765                                 }
 766                                 delegate_instance_expression = null;
 767                         } else
 768                                 delegate_instance_expression = ec.GetThis (loc);
 769
 770                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 771                                 delegate_instance_expression = new BoxedCast (mg.InstanceExpression);
 772
 773                         method_group = mg;
 774                         eclass = ExprClass.Value;
 775                         return this;
 776                 }
 777         }
 778
 779         //
 780         // Created from the conversion code
 781         //
 782         public class ImplicitDelegateCreation : DelegateCreation {
 783
 784                 ImplicitDelegateCreation (Type t, Location l)
 785                 {
 786                         type = t;
 787                         loc = l;
 788                 }
 789
 790                 public override Expression DoResolve (EmitContext ec)
 791                 {
 792                         return this;
 793                 }
 794
 795                 static public Expression Create (EmitContext ec, MethodGroupExpr mge, Type target_type, Location loc)
 796                 {
 797                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 798                         if (d.ResolveConstructorMethod (ec))
 799                                 return d.ResolveMethodGroupExpr (ec, mge);
 800                         else
 801                                 return null;
 802                 }
 803         }
 804
 805         //
 806         // A delegate-creation-expression, invoked from the `New' class
 807         //
 808         public class NewDelegate : DelegateCreation {
 809                 public ArrayList Arguments;
 810
 811                 //
 812                 // This constructor is invoked from the `New' expression
 813                 //
 814                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 815                 {
 816                         this.type = type;
 817                         this.Arguments = Arguments;
 818                         this.loc  = loc;
 819                 }
 820
 821                 public override Expression DoResolve (EmitContext ec)
 822                 {
 823                         if (Arguments == null || Arguments.Count != 1) {
 824                                 Report.Error (149, loc,
 825                                               "Method name expected");
 826                                 return null;
 827                         }
 828
 829                         if (!ResolveConstructorMethod (ec))
 830                                 return null;
 831
 832                         Argument a = (Argument) Arguments [0];
 833
 834                         if (!a.ResolveMethodGroup (ec, loc))
 835                                 return null;
 836
 837                         Expression e = a.Expr;
 838
 839                         MethodGroupExpr mg = e as MethodGroupExpr;
 840                         if (mg != null)
 841                                 return ResolveMethodGroupExpr (ec, mg);
 842
 843                         Type e_type = e.Type;
 844
 845                         if (!TypeManager.IsDelegateType (e_type)) {
 846                                 e.Error_UnexpectedKind ("method", loc);
 847                                 return null;
 848                         }
 849
 850                         method_group = Expression.MemberLookup (
 851                                 ec, type, "Invoke", MemberTypes.Method,
 852                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 853
 854                         if (method_group == null) {
 855                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 856                                 return null;
 857                         }
 858
 859                         // This is what MS' compiler reports. We could always choose
 860                         // to be more verbose and actually give delegate-level specifics
 861                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 862                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 863                                               "to type '" + type + "'");
 864                                 return null;
 865                         }
 866
 867                         delegate_instance_expression = e;
 868                         delegate_method = method_group.Methods [0];
 869
 870                         eclass = ExprClass.Value;
 871                         return this;
 872                 }
 873         }
 874
 875         public class DelegateInvocation : ExpressionStatement {
 876
 877                 public Expression InstanceExpr;
 878                 public ArrayList  Arguments;
 879
 880                 MethodBase method;
 881
 882                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 883                 {
 884                         this.InstanceExpr = instance_expr;
 885                         this.Arguments = args;
 886                         this.loc = loc;
 887                 }
 888
 889                 public override Expression DoResolve (EmitContext ec)
 890                 {
 891                         if (InstanceExpr is EventExpr) {
 892
 893                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 894
 895                                 Expression ml = MemberLookup (
 896                                         ec, ec.ContainerType, ei.Name,
 897                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 898
 899                                 if (ml == null) {
 900                                         //
 901                                         // If this is the case, then the Event does not belong
 902                                         // to this Type and so, according to the spec
 903                                         // cannot be accessed directly
 904                                         //
 905                                         // Note that target will not appear as an EventExpr
 906                                         // in the case it is being referenced within the same type container;
 907                                         // it will appear as a FieldExpr in that case.
 908                                         //
 909
 910                                         Assign.error70 (ei, loc);
 911                                         return null;
 912                                 }
 913                         }
 914
 915
 916                         Type del_type = InstanceExpr.Type;
 917                         if (del_type == null)
 918                                 return null;
 919
 920                         if (Arguments != null){
 921                                 foreach (Argument a in Arguments){
 922                                         if (!a.Resolve (ec, loc))
 923                                                 return null;
 924                                 }
 925                         }
 926
 927                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
 928                                 return null;
 929
 930                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
 931                         if (!(lookup is MethodGroupExpr)) {
 932                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 933                                 return null;
 934                         }
 935
 936                         method = ((MethodGroupExpr) lookup).Methods [0];
 937                         type = ((MethodInfo) method).ReturnType;
 938                         eclass = ExprClass.Value;
 939
 940                         return this;
 941                 }
 942
 943                 public override void Emit (EmitContext ec)
 944                 {
 945                         //
 946                         // Invocation on delegates call the virtual Invoke member
 947                         // so we are always `instance' calls
 948                         //
 949                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
 950                 }
 951
 952                 public override void EmitStatement (EmitContext ec)
 953                 {
 954                         Emit (ec);
 955                         //
 956                         // Pop the return value if there is one
 957                         //
 958                         if (method is MethodInfo){
 959                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
 960                                         ec.ig.Emit (OpCodes.Pop);
 961                         }
 962                 }
 963
 964         }
 965 }