mcs/gmcs/generic.cs

   1 //
   2 // generic.cs: Support classes for generics
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2003 Ximian, Inc.
   8 //
   9 using System;
  10 using System.Reflection;
  11 using System.Reflection.Emit;
  12 using System.Globalization;
  13 using System.Collections;
  14 using System.Text;
  15
  16 namespace Mono.CSharp {
  17
  18         //
  19         // Tracks the constraints for a type parameter
  20         //
  21         public class Constraints {
  22                 string type_parameter;
  23                 ArrayList constraints;
  24                 Location loc;
  25
  26                 //
  27                 // type_parameter is the identifier, constraints is an arraylist of
  28                 // Expressions (with types) or `true' for the constructor constraint.
  29                 //
  30                 public Constraints (string type_parameter, ArrayList constraints,
  31                                     Location loc)
  32                 {
  33                         this.type_parameter = type_parameter;
  34                         this.constraints = constraints;
  35                         this.loc = loc;
  36                 }
  37
  38                 public string TypeParameter {
  39                         get {
  40                                 return type_parameter;
  41                         }
  42                 }
  43
  44                 protected void Error (string message)
  45                 {
  46                         Report.Error (-218, "Invalid constraints clause for type " +
  47                                       "parameter `{0}': {1}", type_parameter, message);
  48                 }
  49
  50                 bool has_ctor_constraint;
  51                 TypeExpr class_constraint;
  52                 ArrayList iface_constraints;
  53                 TypeExpr[] constraint_types;
  54                 int num_constraints;
  55
  56                 public bool HasConstructorConstraint {
  57                         get { return has_ctor_constraint; }
  58                 }
  59
  60                 public bool Resolve (DeclSpace ds)
  61                 {
  62                         iface_constraints = new ArrayList ();
  63
  64                         foreach (object obj in constraints) {
  65                                 if (has_ctor_constraint) {
  66                                         Error ("can only use one constructor constraint and " +
  67                                                "it must be the last constraint in the list.");
  68                                         return false;
  69                                 }
  70
  71                                 if (obj is bool) {
  72                                         has_ctor_constraint = true;
  73                                         continue;
  74                                 }
  75
  76                                 TypeExpr expr = ds.ResolveTypeExpr ((Expression) obj, false, loc);
  77                                 if (expr == null)
  78                                         return false;
  79
  80                                 if (expr.IsInterface)
  81                                         iface_constraints.Add (expr);
  82                                 else if (class_constraint != null) {
  83                                         Error ("can have at most one class constraint.");
  84                                         return false;
  85                                 } else
  86                                         class_constraint = expr;
  87
  88                                 num_constraints++;
  89                         }
  90
  91                         constraint_types = new TypeExpr [num_constraints];
  92                         int pos = 0;
  93                         if (class_constraint != null)
  94                                 constraint_types [pos++] = class_constraint;
  95                         iface_constraints.CopyTo (constraint_types, pos);
  96
  97                         return true;
  98                 }
  99
 100                 public Type[] ResolveTypes (EmitContext ec)
 101                 {
 102                         Type [] types = new Type [constraint_types.Length];
 103
 104                         for (int i = 0; i < constraint_types.Length; i++)
 105                                 types [i] = constraint_types [i].ResolveType (ec);
 106
 107                         return types;
 108                 }
 109         }
 110
 111         //
 112         // This type represents a generic type parameter
 113         //
 114         public class TypeParameter {
 115                 string name;
 116                 Constraints constraints;
 117                 Location loc;
 118                 Type type;
 119
 120                 public TypeParameter (string name, Constraints constraints, Location loc)
 121                 {
 122                         this.name = name;
 123                         this.constraints = constraints;
 124                         this.loc = loc;
 125                 }
 126
 127                 public string Name {
 128                         get {
 129                                 return name;
 130                         }
 131                 }
 132
 133                 public Location Location {
 134                         get {
 135                                 return loc;
 136                         }
 137                 }
 138
 139                 public Constraints Constraints {
 140                         get {
 141                                 return constraints;
 142                         }
 143                 }
 144
 145                 public Type Type {
 146                         get {
 147                                 return type;
 148                         }
 149                 }
 150
 151                 public bool Resolve (DeclSpace ds)
 152                 {
 153                         if (constraints != null)
 154                                 return constraints.Resolve (ds);
 155
 156                         return true;
 157                 }
 158
 159                 public Type Define (TypeBuilder tb)
 160                 {
 161                         type = tb.DefineGenericParameter (name);
 162                         return type;
 163                 }
 164
 165                 public Type DefineMethod (MethodBuilder mb)
 166                 {
 167                         type = mb.DefineGenericParameter (name);
 168                         return type;
 169                 }
 170
 171                 public void DefineType (EmitContext ec, TypeBuilder tb)
 172                 {
 173                         int index = type.GenericParameterPosition;
 174                         if (constraints == null)
 175                                 tb.SetGenericParameterConstraints (index, new Type [0]);
 176                         else
 177                                 tb.SetGenericParameterConstraints (index, constraints.ResolveTypes (ec));
 178                 }
 179
 180                 public void DefineType (EmitContext ec, MethodBuilder mb)
 181                 {
 182                         int index = type.GenericParameterPosition;
 183                         if (constraints == null)
 184                                 mb.SetGenericParameterConstraints (index, new Type [0]);
 185                         else
 186                                 mb.SetGenericParameterConstraints (index, constraints.ResolveTypes (ec));
 187                 }
 188
 189                 public override string ToString ()
 190                 {
 191                         return "TypeParameter[" + name + "]";
 192                 }
 193         }
 194
 195         //
 196         // This type represents a generic type parameter reference.
 197         //
 198         // These expressions are born in a fully resolved state.
 199         //
 200         public class TypeParameterExpr : TypeExpr {
 201                 TypeParameter type_parameter;
 202
 203                 public override string Name {
 204                         get {
 205                                 return type_parameter.Name;
 206                         }
 207                 }
 208
 209                 public TypeParameter TypeParameter {
 210                         get {
 211                                 return type_parameter;
 212                         }
 213                 }
 214
 215                 public TypeParameterExpr (TypeParameter type_parameter, Location loc)
 216                 {
 217                         this.type_parameter = type_parameter;
 218                 }
 219
 220                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
 221                 {
 222                         type = type_parameter.Type;
 223
 224                         return this;
 225                 }
 226
 227                 public void Error_CannotUseAsUnmanagedType (Location loc)
 228                 {
 229                         Report.Error (-203, loc, "Can not use type parameter as unamanged type");
 230                 }
 231         }
 232
 233         public class TypeArguments {
 234                 ArrayList args;
 235                 Type[] atypes;
 236                 bool has_type_args;
 237
 238                 public TypeArguments ()
 239                 {
 240                         args = new ArrayList ();
 241                 }
 242
 243                 public void Add (Expression type)
 244                 {
 245                         args.Add (type);
 246                 }
 247
 248                 public void Add (TypeArguments new_args)
 249                 {
 250                         args.AddRange (new_args.args);
 251                 }
 252
 253                 public Type[] Arguments {
 254                         get {
 255                                 return atypes;
 256                         }
 257                 }
 258
 259                 public bool HasTypeArguments {
 260                         get {
 261                                 return has_type_args;
 262                         }
 263                 }
 264
 265                 public override string ToString ()
 266                 {
 267                         StringBuilder s = new StringBuilder ();
 268
 269                         int count = args.Count;
 270                         for (int i = 0; i < count; i++){
 271                                 //
 272                                 // FIXME: Use TypeManager.CSharpname once we have the type
 273                                 //
 274                                 s.Append (args [i].ToString ());
 275                                 if (i+1 < count)
 276                                         s.Append (", ");
 277                         }
 278                         return s.ToString ();
 279                 }
 280
 281                 public bool Resolve (EmitContext ec)
 282                 {
 283                         int count = args.Count;
 284                         bool ok = true;
 285
 286                         atypes = new Type [count];
 287
 288                         for (int i = 0; i < count; i++){
 289                                 TypeExpr e = ((Expression)args [i]).ResolveAsTypeTerminal (ec);
 290                                 if (e == null) {
 291                                         ok = false;
 292                                         continue;
 293                                 }
 294                                 if (e is TypeParameterExpr)
 295                                         has_type_args = true;
 296                                 args [i] = e;
 297                                 atypes [i] = e.ResolveType (ec);
 298
 299                                 if (atypes [i] == null)
 300                                         ok = false;
 301                         }
 302                         return ok;
 303                 }
 304         }
 305
 306         public class ConstructedType : TypeExpr {
 307                 string name, full_name;
 308                 TypeArguments args;
 309                 Type[] gen_params, atypes;
 310                 Type gt;
 311
 312                 public ConstructedType (string name, TypeArguments args, Location l)
 313                 {
 314                         loc = l;
 315                         this.name = name;
 316                         this.args = args;
 317
 318                         eclass = ExprClass.Type;
 319                         full_name = name + "<" + args.ToString () + ">";
 320                 }
 321
 322                 public ConstructedType (string name, TypeParameter[] type_params, Location l)
 323                 {
 324                         loc = l;
 325                         this.name = name;
 326
 327                         args = new TypeArguments ();
 328                         foreach (TypeParameter type_param in type_params)
 329                                 args.Add (new TypeParameterExpr (type_param, l));
 330
 331                         eclass = ExprClass.Type;
 332                         full_name = name + "<" + args.ToString () + ">";
 333                 }
 334
 335                 public ConstructedType (Type t, TypeParameter[] type_params, Location l)
 336                         : this (t.Name, type_params, l)
 337                 {
 338                         gt = t.GetGenericTypeDefinition ();
 339                 }
 340
 341                 public ConstructedType (Type t, TypeArguments args, Location l)
 342                         : this (t.Name, args, l)
 343                 {
 344                         gt = t.GetGenericTypeDefinition ();
 345                 }
 346
 347                 public TypeArguments TypeArguments {
 348                         get { return args; }
 349                 }
 350
 351                 protected bool CheckConstraints (int index)
 352                 {
 353                         Type atype = atypes [index];
 354                         Type ptype = gen_params [index];
 355
 356                         //// FIXME
 357                         return true;
 358
 359                         //
 360                         // First, check parent class.
 361                         //
 362                         if ((ptype.BaseType != atype.BaseType) &&
 363                             !atype.BaseType.IsSubclassOf (ptype.BaseType)) {
 364                                 Report.Error (-219, loc, "Cannot create constructed type `{0}': " +
 365                                               "type argument `{1}' must derive from `{2}'.",
 366                                               full_name, atype, ptype.BaseType);
 367                                 return false;
 368                         }
 369
 370                         //
 371                         // Now, check the interfaces.
 372                         //
 373                         foreach (Type itype in ptype.GetInterfaces ()) {
 374                                 if (TypeManager.ImplementsInterface (atype, itype))
 375                                         continue;
 376
 377                                 Report.Error (-219, loc, "Cannot create constructed type `{0}: " +
 378                                               "type argument `{1}' must implement interface `{2}'.",
 379                                               full_name, atype, itype);
 380                                 return false;
 381                         }
 382
 383                         return true;
 384                 }
 385
 386                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
 387                 {
 388                         if (gt != null)
 389                                 return this;
 390
 391                         //
 392                         // First, resolve the generic type.
 393                         //
 394                         SimpleName sn = new SimpleName (name, loc);
 395                         TypeExpr resolved = sn.ResolveAsTypeTerminal (ec);
 396                         if (resolved == null)
 397                                 return null;
 398
 399                         if (resolved.Type == null) {
 400                                 Report.Error (-220, loc, "Failed to resolve constructed type `{0}'",
 401                                               full_name);
 402                                 return null;
 403                         }
 404
 405                         gt = resolved.Type.GetGenericTypeDefinition ();
 406                         return this;
 407                 }
 408
 409                 public override Type ResolveType (EmitContext ec)
 410                 {
 411                         if (type != null)
 412                                 return type;
 413                         if (DoResolveAsTypeStep (ec) == null)
 414                                 return null;
 415
 416                         //
 417                         // Resolve the arguments.
 418                         //
 419                         if (args.Resolve (ec) == false) {
 420                                 Report.Error (-220, loc, "Failed to resolve constructed type `{0}'",
 421                                               full_name);
 422                                 return null;
 423                         }
 424
 425                         gen_params = gt.GetGenericArguments ();
 426
 427                         DeclSpace decl = ec.DeclSpace, parent = null;
 428                         while (decl != null) {
 429                                 if (TypeManager.IsNestedChildOf (gt, decl.TypeBuilder)) {
 430                                         parent = decl;
 431                                         break;
 432                                 }
 433                                 decl = decl.Parent;
 434                         }
 435
 436                         if (parent != null) {
 437                                 TypeParameter[] pparams = parent.TypeParameters;
 438
 439                                 atypes = new Type [args.Arguments.Length + pparams.Length];
 440                                 for (int i = 0; i < pparams.Length; i++) {
 441                                         TypeParameter pparam = pparams [i];
 442                                         if (pparam.Type == null)
 443                                                 throw new Exception ();
 444                                         atypes [i] = pparam.Type;
 445                                 }
 446                                 args.Arguments.CopyTo (atypes, pparams.Length);
 447                         } else
 448                                 atypes = args.Arguments;
 449
 450                         if (atypes.Length != gen_params.Length) {
 451                                 Report.Error (-217, loc, "Generic type `{0}' takes {1} " +
 452                                               "type parameters, but specified {2}.", gt.Name,
 453                                               gen_params.Length, atypes.Length);
 454                                 return null;
 455                         }
 456
 457                         for (int i = 0; i < gen_params.Length; i++) {
 458                                 if (!CheckConstraints (i))
 459                                         return null;
 460                         }
 461
 462                         //
 463                         // Now bind the parameters.
 464                         //
 465                         type = gt.BindGenericParameters (atypes);
 466                         return type;
 467                 }
 468
 469                 public Expression GetMemberAccess (TypeExpr current_type)
 470                 {
 471                         return new GenericMemberAccess (current_type, name, args, loc);
 472                 }
 473
 474                 public override bool CheckAccessLevel (DeclSpace ds)
 475                 {
 476                         return ds.CheckAccessLevel (gt);
 477                 }
 478
 479                 public override bool AsAccessible (DeclSpace ds, int flags)
 480                 {
 481                         return ds.AsAccessible (gt, flags);
 482                 }
 483
 484                 public override bool IsClass {
 485                         get { return gt.IsClass; }
 486                 }
 487
 488                 public override bool IsValueType {
 489                         get { return gt.IsValueType; }
 490                 }
 491
 492                 public override bool IsInterface {
 493                         get { return gt.IsInterface; }
 494                 }
 495
 496                 public override bool IsSealed {
 497                         get { return gt.IsSealed; }
 498                 }
 499
 500                 public override TypeExpr[] GetInterfaces ()
 501                 {
 502                         TypeExpr[] ifaces = TypeManager.GetInterfaces (gt);
 503                         return ifaces;
 504                 }
 505
 506                 public override string Name {
 507                         get {
 508                                 return full_name;
 509                         }
 510                 }
 511         }
 512
 513         public class GenericMethod : DeclSpace
 514         {
 515                 public GenericMethod (NamespaceEntry ns, TypeContainer parent, string name,
 516                                       Attributes attrs, Location l)
 517                         : base (ns, parent, name, attrs, l)
 518                 { }
 519
 520                 public override TypeBuilder DefineType ()
 521                 {
 522                         throw new Exception ();
 523                 }
 524
 525                 public override bool Define (TypeContainer parent)
 526                 {
 527                         return true;
 528                 }
 529
 530                 public bool Define (MethodBuilder mb)
 531                 {
 532                         Type[] gen_params = new Type [TypeParameters.Length];
 533                         for (int i = 0; i < TypeParameters.Length; i++)
 534                                 gen_params [i] = TypeParameters [i].DefineMethod (mb);
 535
 536                         return true;
 537                 }
 538
 539                 public bool DefineType (EmitContext ec, MethodBuilder mb)
 540                 {
 541                         for (int i = 0; i < TypeParameters.Length; i++)
 542                                 TypeParameters [i].DefineType (ec, mb);
 543
 544                         return true;
 545                 }
 546
 547                 public override bool DefineMembers (TypeContainer parent)
 548                 {
 549                         return true;
 550                 }
 551
 552                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 553                                                         MemberFilter filter, object criteria)
 554                 {
 555                         throw new Exception ();
 556                 }
 557
 558                 public override MemberCache MemberCache {
 559                         get {
 560                                 throw new Exception ();
 561                         }
 562                 }
 563         }
 564
 565         public class GenericMemberAccess : MemberAccess
 566         {
 567                 TypeArguments args;
 568
 569                 public GenericMemberAccess (Expression expr, string id, TypeArguments args, Location loc)
 570                         : base (expr, id, loc)
 571                 {
 572                         this.args = args;
 573                 }
 574
 575                 public override Expression DoResolve (EmitContext ec, Expression right_side,
 576                                                       ResolveFlags flags)
 577                 {
 578                         Expression expr = base.DoResolve (ec, right_side, flags);
 579                         if (expr == null)
 580                                 return null;
 581
 582                         MethodGroupExpr mg = expr as MethodGroupExpr;
 583                         if (mg == null) {
 584                                 Report.Error (-220, loc, "Member `{0}' has type arguments, but did " +
 585                                               "not resolve as a method group.", Identifier);
 586                                 return null;
 587                         }
 588
 589                         if (args.Resolve (ec) == false)
 590                                 return null;
 591
 592                         Type[] atypes = args.Arguments;
 593
 594                         ArrayList list = new ArrayList ();
 595
 596                         foreach (MethodBase method in mg.Methods) {
 597                                 MethodInfo mi = method as MethodInfo;
 598                                 if (mi == null)
 599                                         continue;
 600
 601                                 Type[] gen_params = mi.GetGenericArguments ();
 602
 603                                 if (atypes.Length != gen_params.Length) {
 604                                         Report.Error (-217, loc, "Generic method `{0}' takes {1} " +
 605                                                       "type parameters, but specified {2}.", mi.Name,
 606                                                       gen_params.Length, atypes.Length);
 607                                         continue;
 608                                 }
 609
 610                                 list.Add (mi.BindGenericParameters (args.Arguments));
 611                         }
 612
 613                         MethodInfo[] methods = new MethodInfo [list.Count];
 614                         list.CopyTo (methods, 0);
 615
 616                         MethodGroupExpr new_mg = new MethodGroupExpr (methods, mg.Location);
 617                         new_mg.InstanceExpression = mg.InstanceExpression;
 618                         return new_mg;
 619                 }
 620
 621                 public override Expression ResolveAsTypeStep (EmitContext ec)
 622                 {
 623                         ConstructedType cexpr = expr as ConstructedType;
 624                         if (cexpr == null)
 625                                 throw new Exception ();
 626
 627                         expr = base.ResolveAsTypeStep (ec);
 628                         if (expr == null)
 629                                 return null;
 630
 631                         Type t = ((TypeExpr) expr).ResolveType (ec);
 632                         if (t == null)
 633                                 return null;
 634
 635                         TypeArguments new_args = new TypeArguments ();
 636                         new_args.Add (cexpr.TypeArguments);
 637                         new_args.Add (args);
 638
 639                         ConstructedType ctype = new ConstructedType (t, new_args, loc);
 640                         return ctype.ResolveAsTypeStep (ec);
 641                 }
 642         }
 643
 644         public class DefaultValueExpression : Expression
 645         {
 646                 Expression expr;
 647                 LocalTemporary temp_storage;
 648
 649                 public DefaultValueExpression (Expression expr, Location loc)
 650                 {
 651                         this.expr = expr;
 652                         this.loc = loc;
 653                 }
 654
 655                 public override Expression DoResolve (EmitContext ec)
 656                 {
 657                         type = ec.DeclSpace.ResolveType (expr, false, loc);
 658                         if (type == null)
 659                                 return null;
 660
 661                         if (type.IsGenericParameter || TypeManager.IsValueType (type))
 662                                 temp_storage = new LocalTemporary (ec, type);
 663
 664                         eclass = ExprClass.Variable;
 665                         return this;
 666                 }
 667
 668                 public override void Emit (EmitContext ec)
 669                 {
 670                         if (temp_storage != null) {
 671                                 temp_storage.AddressOf (ec, AddressOp.LoadStore);
 672                                 ec.ig.Emit (OpCodes.Initobj, type);
 673                                 temp_storage.Emit (ec);
 674                         } else
 675                                 ec.ig.Emit (OpCodes.Ldnull);
 676                 }
 677         }
 678 }