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 Type[] Arguments {
 249                         get {
 250                                 return atypes;
 251                         }
 252                 }
 253
 254                 public bool HasTypeArguments {
 255                         get {
 256                                 return has_type_args;
 257                         }
 258                 }
 259
 260                 public override string ToString ()
 261                 {
 262                         StringBuilder s = new StringBuilder ();
 263
 264                         int count = args.Count;
 265                         for (int i = 0; i < count; i++){
 266                                 //
 267                                 // FIXME: Use TypeManager.CSharpname once we have the type
 268                                 //
 269                                 s.Append (args [i].ToString ());
 270                                 if (i+1 < count)
 271                                         s.Append (", ");
 272                         }
 273                         return s.ToString ();
 274                 }
 275
 276                 public bool Resolve (EmitContext ec)
 277                 {
 278                         int count = args.Count;
 279                         bool ok = true;
 280
 281                         atypes = new Type [count];
 282
 283                         for (int i = 0; i < count; i++){
 284                                 TypeExpr e = ((Expression)args [i]).ResolveAsTypeTerminal (ec);
 285                                 if (e == null) {
 286                                         ok = false;
 287                                         continue;
 288                                 }
 289                                 if (e is TypeParameterExpr)
 290                                         has_type_args = true;
 291                                 args [i] = e;
 292                                 atypes [i] = e.ResolveType (ec);
 293
 294                                 if (atypes [i] == null)
 295                                         ok = false;
 296                         }
 297                         return ok;
 298                 }
 299         }
 300
 301         public class ConstructedType : TypeExpr {
 302                 string name, full_name;
 303                 TypeArguments args;
 304                 Type[] gen_params, atypes;
 305                 Type gt;
 306
 307                 public ConstructedType (string name, TypeArguments args, Location l)
 308                 {
 309                         loc = l;
 310                         this.name = name;
 311                         this.args = args;
 312
 313                         eclass = ExprClass.Type;
 314                         full_name = name + "<" + args.ToString () + ">";
 315                 }
 316
 317                 public ConstructedType (string name, TypeParameter[] type_params, Location l)
 318                 {
 319                         loc = l;
 320                         this.name = name;
 321
 322                         args = new TypeArguments ();
 323                         foreach (TypeParameter type_param in type_params)
 324                                 args.Add (new TypeParameterExpr (type_param, l));
 325
 326                         eclass = ExprClass.Type;
 327                         full_name = name + "<" + args.ToString () + ">";
 328                 }
 329
 330                 protected bool CheckConstraints (int index)
 331                 {
 332                         Type atype = args.Arguments [index];
 333                         Type ptype = gen_params [index];
 334
 335                         //// FIXME
 336                         return true;
 337
 338                         //
 339                         // First, check parent class.
 340                         //
 341                         if ((ptype.BaseType != atype.BaseType) &&
 342                             !atype.BaseType.IsSubclassOf (ptype.BaseType)) {
 343                                 Report.Error (-219, loc, "Cannot create constructed type `{0}': " +
 344                                               "type argument `{1}' must derive from `{2}'.",
 345                                               full_name, atype, ptype.BaseType);
 346                                 return false;
 347                         }
 348
 349                         //
 350                         // Now, check the interfaces.
 351                         //
 352                         foreach (Type itype in ptype.GetInterfaces ()) {
 353                                 if (TypeManager.ImplementsInterface (atype, itype))
 354                                         continue;
 355
 356                                 Report.Error (-219, loc, "Cannot create constructed type `{0}: " +
 357                                               "type argument `{1}' must implement interface `{2}'.",
 358                                               full_name, atype, itype);
 359                                 return false;
 360                         }
 361
 362                         return true;
 363                 }
 364
 365                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
 366                 {
 367                         if (gt != null)
 368                                 return this;
 369
 370                         //
 371                         // First, resolve the generic type.
 372                         //
 373                         SimpleName sn = new SimpleName (name, loc);
 374                         TypeExpr resolved = sn.ResolveAsTypeTerminal (ec);
 375                         if (resolved == null)
 376                                 return null;
 377
 378                         if (resolved.Type == null) {
 379                                 Report.Error (-220, loc, "Failed to resolve constructed type `{0}'",
 380                                               full_name);
 381                                 return null;
 382                         }
 383
 384                         gt = resolved.Type.GetGenericTypeDefinition ();
 385                         return this;
 386                 }
 387
 388                 public override Type ResolveType (EmitContext ec)
 389                 {
 390                         if (type != null)
 391                                 return type;
 392                         if (DoResolveAsTypeStep (ec) == null)
 393                                 return null;
 394
 395                         //
 396                         // Resolve the arguments.
 397                         //
 398                         if (args.Resolve (ec) == false) {
 399                                 Report.Error (-220, loc, "Failed to resolve constructed type `{0}'",
 400                                               full_name);
 401                                 return null;
 402                         }
 403
 404                         gen_params = gt.GetGenericArguments ();
 405                         atypes = args.Arguments;
 406
 407                         if (atypes.Length != gen_params.Length) {
 408                                 Report.Error (-217, loc, "Generic type `{0}' takes {1} " +
 409                                               "type parameters, but specified {2}.", gt.Name,
 410                                               gen_params.Length, atypes.Length);
 411                                 return null;
 412                         }
 413
 414                         for (int i = 0; i < gen_params.Length; i++) {
 415                                 if (!CheckConstraints (i))
 416                                         return null;
 417                         }
 418
 419                         //
 420                         // Now bind the parameters.
 421                         //
 422                         type = gt.BindGenericParameters (atypes);
 423                         return type;
 424                 }
 425
 426                 public Expression GetMemberAccess (TypeExpr current_type)
 427                 {
 428                         return new GenericMemberAccess (current_type, name, args, loc);
 429                 }
 430
 431                 public override bool CheckAccessLevel (DeclSpace ds)
 432                 {
 433                         return ds.CheckAccessLevel (gt);
 434                 }
 435
 436                 public override bool AsAccessible (DeclSpace ds, int flags)
 437                 {
 438                         return ds.AsAccessible (gt, flags);
 439                 }
 440
 441                 public override bool IsClass {
 442                         get { return gt.IsClass; }
 443                 }
 444
 445                 public override bool IsValueType {
 446                         get { return gt.IsValueType; }
 447                 }
 448
 449                 public override bool IsInterface {
 450                         get { return gt.IsInterface; }
 451                 }
 452
 453                 public override bool IsSealed {
 454                         get { return gt.IsSealed; }
 455                 }
 456
 457                 public override TypeExpr[] GetInterfaces ()
 458                 {
 459                         TypeExpr[] ifaces = TypeManager.GetInterfaces (gt);
 460                         return ifaces;
 461                 }
 462
 463                 public override string Name {
 464                         get {
 465                                 return full_name;
 466                         }
 467                 }
 468         }
 469
 470         public class GenericMethod : DeclSpace
 471         {
 472                 public GenericMethod (NamespaceEntry ns, TypeContainer parent, string name,
 473                                       Attributes attrs, Location l)
 474                         : base (ns, parent, name, attrs, l)
 475                 { }
 476
 477                 public override TypeBuilder DefineType ()
 478                 {
 479                         throw new Exception ();
 480                 }
 481
 482                 public override bool Define (TypeContainer parent)
 483                 {
 484                         return true;
 485                 }
 486
 487                 public bool Define (MethodBuilder mb)
 488                 {
 489                         Type[] gen_params = new Type [TypeParameters.Length];
 490                         for (int i = 0; i < TypeParameters.Length; i++)
 491                                 gen_params [i] = TypeParameters [i].DefineMethod (mb);
 492
 493                         return true;
 494                 }
 495
 496                 public override bool DefineMembers (TypeContainer parent)
 497                 {
 498                         return true;
 499                 }
 500
 501                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 502                                                         MemberFilter filter, object criteria)
 503                 {
 504                         throw new Exception ();
 505                 }
 506
 507                 public override MemberCache MemberCache {
 508                         get {
 509                                 throw new Exception ();
 510                         }
 511                 }
 512         }
 513
 514         public class GenericMemberAccess : MemberAccess
 515         {
 516                 TypeArguments args;
 517
 518                 public GenericMemberAccess (Expression expr, string id, TypeArguments args, Location loc)
 519                         : base (expr, id, loc)
 520                 {
 521                         this.args = args;
 522                 }
 523
 524                 public override Expression DoResolve (EmitContext ec, Expression right_side,
 525                                                       ResolveFlags flags)
 526                 {
 527                         Expression expr = base.DoResolve (ec, right_side, flags);
 528                         if (expr == null)
 529                                 return null;
 530
 531                         MethodGroupExpr mg = expr as MethodGroupExpr;
 532                         if (mg == null) {
 533                                 Report.Error (-220, loc, "Member `{0}' has type arguments, but did " +
 534                                               "not resolve as a method group.", Identifier);
 535                                 return null;
 536                         }
 537
 538                         if (args.Resolve (ec) == false)
 539                                 return null;
 540
 541                         Type[] atypes = args.Arguments;
 542
 543                         ArrayList list = new ArrayList ();
 544
 545                         foreach (MethodBase method in mg.Methods) {
 546                                 MethodInfo mi = method as MethodInfo;
 547                                 if (mi == null)
 548                                         continue;
 549
 550                                 Type[] gen_params = mi.GetGenericArguments ();
 551
 552                                 if (atypes.Length != gen_params.Length) {
 553                                         Report.Error (-217, loc, "Generic method `{0}' takes {1} " +
 554                                                       "type parameters, but specified {2}.", mi.Name,
 555                                                       gen_params.Length, atypes.Length);
 556                                         continue;
 557                                 }
 558
 559                                 list.Add (mi.BindGenericParameters (args.Arguments));
 560                         }
 561
 562                         MethodInfo[] methods = new MethodInfo [list.Count];
 563                         list.CopyTo (methods, 0);
 564
 565                         MethodGroupExpr new_mg = new MethodGroupExpr (methods, mg.Location);
 566                         new_mg.InstanceExpression = mg.InstanceExpression;
 567                         return new_mg;
 568                 }
 569         }
 570
 571         public class DefaultValueExpression : Expression
 572         {
 573                 Expression expr;
 574                 LocalTemporary temp_storage;
 575
 576                 public DefaultValueExpression (Expression expr, Location loc)
 577                 {
 578                         this.expr = expr;
 579                         this.loc = loc;
 580                 }
 581
 582                 public override Expression DoResolve (EmitContext ec)
 583                 {
 584                         type = ec.DeclSpace.ResolveType (expr, false, loc);
 585                         if (type == null)
 586                                 return null;
 587
 588                         if (type.IsGenericParameter || TypeManager.IsValueType (type))
 589                                 temp_storage = new LocalTemporary (ec, type);
 590
 591                         eclass = ExprClass.Variable;
 592                         return this;
 593                 }
 594
 595                 public override void Emit (EmitContext ec)
 596                 {
 597                         if (temp_storage != null) {
 598                                 temp_storage.AddressOf (ec, AddressOp.LoadStore);
 599                                 ec.ig.Emit (OpCodes.Initobj, type);
 600                                 temp_storage.Emit (ec);
 601                         } else
 602                                 ec.ig.Emit (OpCodes.Ldnull);
 603                 }
 604         }
 605 }