mcs/mcs/enum.cs

   1 //
   2 // enum.cs: Enum handling.
   3 //
   4 // Author: Miguel de Icaza (miguel@gnu.org)
   5 //         Ravi Pratap     (ravi@ximian.com)
   6 //
   7 // Licensed under the terms of the GNU GPL
   8 //
   9 // (C) 2001 Ximian, Inc (http://www.ximian.com)
  10 //
  11
  12 using System;
  13 using System.Collections;
  14 using System.Reflection;
  15 using System.Reflection.Emit;
  16
  17 namespace Mono.CSharp {
  18
  19         /// <summary>
  20         ///   Enumeration container
  21         /// </summary>
  22         public class Enum : DeclSpace {
  23                 ArrayList ordered_enums;
  24
  25                 public Expression BaseType;
  26                 public Attributes  OptAttributes;
  27
  28                 public Type UnderlyingType;
  29
  30                 Hashtable member_to_location;
  31                 Hashtable member_to_attributes;
  32
  33                 //
  34                 // This is for members that have been defined
  35                 //
  36                 Hashtable member_to_value;
  37
  38                 //
  39                 // This is used to mark members we're currently defining
  40                 //
  41                 Hashtable in_transit;
  42
  43                 ArrayList field_builders;
  44
  45                 public const int AllowedModifiers =
  46                         Modifiers.NEW |
  47                         Modifiers.PUBLIC |
  48                         Modifiers.PROTECTED |
  49                         Modifiers.INTERNAL |
  50                         Modifiers.PRIVATE;
  51
  52                 public Enum (TypeContainer parent, Expression type, int mod_flags, string name, Attributes attrs, Location l)
  53                         : base (parent, name, l)
  54                 {
  55                         this.BaseType = type;
  56                         ModFlags = Modifiers.Check (AllowedModifiers, mod_flags,
  57                                                     IsTopLevel ? Modifiers.INTERNAL : Modifiers.PRIVATE, l);
  58                         OptAttributes = attrs;
  59
  60                         ordered_enums = new ArrayList ();
  61                         member_to_location = new Hashtable ();
  62                         member_to_value = new Hashtable ();
  63                         in_transit = new Hashtable ();
  64                         field_builders = new ArrayList ();
  65                 }
  66
  67                 /// <summary>
  68                 ///   Adds @name to the enumeration space, with @expr
  69                 ///   being its definition.
  70                 /// </summary>
  71                 public AdditionResult AddEnumMember (string name, Expression expr, Location loc,
  72                                                      Attributes opt_attrs)
  73                 {
  74                         if (defined_names.Contains (name))
  75                                 return AdditionResult.NameExists;
  76
  77                         DefineName (name, expr);
  78
  79                         ordered_enums.Add (name);
  80                         member_to_location.Add (name, loc);
  81
  82                         if (member_to_attributes == null)
  83                                 member_to_attributes = new Hashtable ();
  84
  85                         member_to_attributes.Add (name, opt_attrs);
  86
  87                         return AdditionResult.Success;
  88                 }
  89
  90                 //
  91                 // This is used by corlib compilation: we map from our
  92                 // type to a type that is consumable by the DefineField
  93                 //
  94                 Type MapToInternalType (Type t)
  95                 {
  96                         if (t == TypeManager.int32_type)
  97                                 return typeof (int);
  98                         if (t == TypeManager.int64_type)
  99                                 return typeof (long);
 100                         if (t == TypeManager.uint32_type)
 101                                 return typeof (uint);
 102                         if (t == TypeManager.uint64_type)
 103                                 return typeof (ulong);
 104                         if (t == TypeManager.float_type)
 105                                 return typeof (float);
 106                         if (t == TypeManager.double_type)
 107                                 return typeof (double);
 108                         if (t == TypeManager.byte_type)
 109                                 return typeof (byte);
 110                         if (t == TypeManager.sbyte_type)
 111                                 return typeof (sbyte);
 112                         if (t == TypeManager.char_type)
 113                                 return typeof (char);
 114                         if (t == TypeManager.short_type)
 115                                 return typeof (short);
 116                         if (t == TypeManager.ushort_type)
 117                                 return typeof (ushort);
 118
 119                         throw new Exception ();
 120                 }
 121
 122                 public override TypeBuilder DefineType ()
 123                 {
 124                         if (TypeBuilder != null)
 125                                 return TypeBuilder;
 126
 127                         TypeAttributes attr = Modifiers.TypeAttr (ModFlags, IsTopLevel);
 128
 129                         attr |= TypeAttributes.Class | TypeAttributes.Sealed;
 130
 131                         UnderlyingType = ResolveType (BaseType, false, Location);
 132
 133                         if (UnderlyingType != TypeManager.int32_type &&
 134                             UnderlyingType != TypeManager.uint32_type &&
 135                             UnderlyingType != TypeManager.int64_type &&
 136                             UnderlyingType != TypeManager.uint64_type &&
 137                             UnderlyingType != TypeManager.short_type &&
 138                             UnderlyingType != TypeManager.ushort_type &&
 139                             UnderlyingType != TypeManager.byte_type  &&
 140                             UnderlyingType != TypeManager.char_type  &&
 141                             UnderlyingType != TypeManager.sbyte_type) {
 142                                 Report.Error (1008, Location,
 143                                               "Type byte, sbyte, short, char, ushort, int, uint, " +
 144                                               "long, or ulong expected (got: " +
 145                                               TypeManager.CSharpName (UnderlyingType) + ")");
 146                                 return null;
 147                         }
 148
 149                         if (IsTopLevel) {
 150                                 if (TypeManager.NamespaceClash (Name))
 151                                         return null;
 152
 153                                 ModuleBuilder builder = CodeGen.ModuleBuilder;
 154
 155                                 TypeBuilder = builder.DefineType (Name, attr, TypeManager.enum_type);
 156                         } else {
 157                                 TypeBuilder builder = Parent.TypeBuilder;
 158
 159                                 TypeBuilder = builder.DefineNestedType (
 160                                         Basename, attr, TypeManager.enum_type);
 161                         }
 162
 163                         //
 164                         // Call MapToInternalType for corlib
 165                         //
 166                         TypeBuilder.DefineField ("value__", UnderlyingType,
 167                                                  FieldAttributes.Public | FieldAttributes.SpecialName
 168                                                  | FieldAttributes.RTSpecialName);
 169
 170                         TypeManager.AddEnumType (Name, TypeBuilder, this);
 171
 172                         return TypeBuilder;
 173                 }
 174
 175                 bool IsValidEnumConstant (Expression e)
 176                 {
 177                         if (!(e is Constant))
 178                                 return false;
 179
 180                         if (e is IntConstant || e is UIntConstant || e is LongConstant ||
 181                             e is ByteConstant || e is SByteConstant || e is ShortConstant ||
 182                             e is UShortConstant || e is ULongConstant || e is EnumConstant ||
 183                             e is CharConstant)
 184                                 return true;
 185                         else
 186                                 return false;
 187                 }
 188
 189                 object GetNextDefaultValue (object default_value)
 190                 {
 191                         if (UnderlyingType == TypeManager.int32_type) {
 192                                 int i = (int) default_value;
 193
 194                                 if (i < System.Int32.MaxValue)
 195                                         return ++i;
 196                                 else
 197                                         return null;
 198                         } else if (UnderlyingType == TypeManager.uint32_type) {
 199                                 uint i = (uint) default_value;
 200
 201                                 if (i < System.UInt32.MaxValue)
 202                                         return ++i;
 203                                 else
 204                                         return null;
 205                         } else if (UnderlyingType == TypeManager.int64_type) {
 206                                 long i = (long) default_value;
 207
 208                                 if (i < System.Int64.MaxValue)
 209                                         return ++i;
 210                                 else
 211                                         return null;
 212                         } else if (UnderlyingType == TypeManager.uint64_type) {
 213                                 ulong i = (ulong) default_value;
 214
 215                                 if (i < System.UInt64.MaxValue)
 216                                         return ++i;
 217                                 else
 218                                         return null;
 219                         } else if (UnderlyingType == TypeManager.short_type) {
 220                                 short i = (short) default_value;
 221
 222                                 if (i < System.Int16.MaxValue)
 223                                         return ++i;
 224                                 else
 225                                         return null;
 226                         } else if (UnderlyingType == TypeManager.ushort_type) {
 227                                 ushort i = (ushort) default_value;
 228
 229                                 if (i < System.UInt16.MaxValue)
 230                                         return ++i;
 231                                 else
 232                                         return null;
 233                         } else if (UnderlyingType == TypeManager.byte_type) {
 234                                 byte i = (byte) default_value;
 235
 236                                 if (i < System.Byte.MaxValue)
 237                                         return ++i;
 238                                 else
 239                                         return null;
 240                         } else if (UnderlyingType == TypeManager.sbyte_type) {
 241                                 sbyte i = (sbyte) default_value;
 242
 243                                 if (i < System.SByte.MaxValue)
 244                                         return ++i;
 245                                 else
 246                                         return null;
 247                         }
 248
 249                         return null;
 250                 }
 251
 252                 void Error_ConstantValueCannotBeConverted (object val, Location loc)
 253                 {
 254                         if (val is Constant)
 255                                 Report.Error (31, loc, "Constant value '" + ((Constant) val).AsString () +
 256                                               "' cannot be converted" +
 257                                               " to a " + TypeManager.CSharpName (UnderlyingType));
 258                         else
 259                                 Report.Error (31, loc, "Constant value '" + val +
 260                                               "' cannot be converted" +
 261                                               " to a " + TypeManager.CSharpName (UnderlyingType));
 262                         return;
 263                 }
 264
 265                 /// <summary>
 266                 ///  Determines if a standard implicit conversion exists from
 267                 ///  expr_type to target_type
 268                 /// </summary>
 269                 public static bool ImplicitConversionExists (Type expr_type, Type target_type)
 270                 {
 271                         expr_type = TypeManager.TypeToCoreType (expr_type);
 272
 273                         if (expr_type == TypeManager.void_type)
 274                                 return false;
 275
 276                         if (expr_type == target_type)
 277                                 return true;
 278
 279                         // First numeric conversions
 280
 281                         if (expr_type == TypeManager.sbyte_type){
 282                                 //
 283                                 // From sbyte to short, int, long, float, double.
 284                                 //
 285                                 if ((target_type == TypeManager.int32_type) ||
 286                                     (target_type == TypeManager.int64_type) ||
 287                                     (target_type == TypeManager.double_type) ||
 288                                     (target_type == TypeManager.float_type)  ||
 289                                     (target_type == TypeManager.short_type) ||
 290                                     (target_type == TypeManager.decimal_type))
 291                                         return true;
 292
 293                         } else if (expr_type == TypeManager.byte_type){
 294                                 //
 295                                 // From byte to short, ushort, int, uint, long, ulong, float, double
 296                                 //
 297                                 if ((target_type == TypeManager.short_type) ||
 298                                     (target_type == TypeManager.ushort_type) ||
 299                                     (target_type == TypeManager.int32_type) ||
 300                                     (target_type == TypeManager.uint32_type) ||
 301                                     (target_type == TypeManager.uint64_type) ||
 302                                     (target_type == TypeManager.int64_type) ||
 303                                     (target_type == TypeManager.float_type) ||
 304                                     (target_type == TypeManager.double_type) ||
 305                                     (target_type == TypeManager.decimal_type))
 306                                         return true;
 307
 308                         } else if (expr_type == TypeManager.short_type){
 309                                 //
 310                                 // From short to int, long, float, double
 311                                 //
 312                                 if ((target_type == TypeManager.int32_type) ||
 313                                     (target_type == TypeManager.int64_type) ||
 314                                     (target_type == TypeManager.double_type) ||
 315                                     (target_type == TypeManager.float_type) ||
 316                                     (target_type == TypeManager.decimal_type))
 317                                         return true;
 318
 319                         } else if (expr_type == TypeManager.ushort_type){
 320                                 //
 321                                 // From ushort to int, uint, long, ulong, float, double
 322                                 //
 323                                 if ((target_type == TypeManager.uint32_type) ||
 324                                     (target_type == TypeManager.uint64_type) ||
 325                                     (target_type == TypeManager.int32_type) ||
 326                                     (target_type == TypeManager.int64_type) ||
 327                                     (target_type == TypeManager.double_type) ||
 328                                     (target_type == TypeManager.float_type) ||
 329                                     (target_type == TypeManager.decimal_type))
 330                                         return true;
 331
 332                         } else if (expr_type == TypeManager.int32_type){
 333                                 //
 334                                 // From int to long, float, double
 335                                 //
 336                                 if ((target_type == TypeManager.int64_type) ||
 337                                     (target_type == TypeManager.double_type) ||
 338                                     (target_type == TypeManager.float_type) ||
 339                                     (target_type == TypeManager.decimal_type))
 340                                         return true;
 341
 342                         } else if (expr_type == TypeManager.uint32_type){
 343                                 //
 344                                 // From uint to long, ulong, float, double
 345                                 //
 346                                 if ((target_type == TypeManager.int64_type) ||
 347                                     (target_type == TypeManager.uint64_type) ||
 348                                     (target_type == TypeManager.double_type) ||
 349                                     (target_type == TypeManager.float_type) ||
 350                                     (target_type == TypeManager.decimal_type))
 351                                         return true;
 352
 353                         } else if ((expr_type == TypeManager.uint64_type) ||
 354                                    (expr_type == TypeManager.int64_type)) {
 355                                 //
 356                                 // From long/ulong to float, double
 357                                 //
 358                                 if ((target_type == TypeManager.double_type) ||
 359                                     (target_type == TypeManager.float_type) ||
 360                                     (target_type == TypeManager.decimal_type))
 361                                         return true;
 362
 363                         } else if (expr_type == TypeManager.char_type){
 364                                 //
 365                                 // From char to ushort, int, uint, long, ulong, float, double
 366                                 //
 367                                 if ((target_type == TypeManager.ushort_type) ||
 368                                     (target_type == TypeManager.int32_type) ||
 369                                     (target_type == TypeManager.uint32_type) ||
 370                                     (target_type == TypeManager.uint64_type) ||
 371                                     (target_type == TypeManager.int64_type) ||
 372                                     (target_type == TypeManager.float_type) ||
 373                                     (target_type == TypeManager.double_type) ||
 374                                     (target_type == TypeManager.decimal_type))
 375                                         return true;
 376
 377                         } else if (expr_type == TypeManager.float_type){
 378                                 //
 379                                 // float to double
 380                                 //
 381                                 if (target_type == TypeManager.double_type)
 382                                         return true;
 383                         }
 384
 385                         return false;
 386                 }
 387
 388                 //
 389                 // Horrible, horrible.  But there is no other way we can pass the EmitContext
 390                 // to the recursive definition triggered by the evaluation of a forward
 391                 // expression
 392                 //
 393                 static EmitContext current_ec = null;
 394
 395                 /// <summary>
 396                 ///  This is used to lookup the value of an enum member. If the member is undefined,
 397                 ///  it attempts to define it and return its value
 398                 /// </summary>
 399                 public object LookupEnumValue (EmitContext ec, string name, Location loc)
 400                 {
 401
 402                         object default_value = null;
 403                         Constant c = null;
 404
 405                         default_value = member_to_value [name];
 406
 407                         if (default_value != null)
 408                                 return default_value;
 409
 410                         //
 411                         // This may happen if we're calling a method in System.Enum, for instance
 412                         // Enum.IsDefined().
 413                         //
 414                         if (!defined_names.Contains (name))
 415                                 return null;
 416
 417                         if (in_transit.Contains (name)) {
 418                                 Report.Error (110, loc, "The evaluation of the constant value for `" +
 419                                               Name + "." + name + "' involves a circular definition.");
 420                                 return null;
 421                         }
 422
 423                         //
 424                         // So if the above doesn't happen, we have a member that is undefined
 425                         // We now proceed to define it
 426                         //
 427                         Expression val = this [name];
 428
 429                         if (val == null) {
 430
 431                                 int idx = ordered_enums.IndexOf (name);
 432
 433                                 if (idx == 0)
 434                                         default_value = 0;
 435                                 else {
 436                                         for (int i = 0; i < idx; ++i) {
 437                                                 string n = (string) ordered_enums [i];
 438                                                 Location m_loc = (Mono.CSharp.Location)
 439                                                         member_to_location [n];
 440                                                 in_transit.Add (name, true);
 441
 442                                                 EmitContext old_ec = current_ec;
 443                                                 current_ec = ec;
 444
 445                                                 default_value = LookupEnumValue (ec, n, m_loc);
 446
 447                                                 current_ec = old_ec;
 448
 449                                                 in_transit.Remove (name);
 450                                                 if (default_value == null)
 451                                                         return null;
 452                                         }
 453
 454                                         default_value = GetNextDefaultValue (default_value);
 455                                 }
 456
 457                         } else {
 458                                 bool old = ec.InEnumContext;
 459                                 ec.InEnumContext = true;
 460                                 in_transit.Add (name, true);
 461
 462                                 EmitContext old_ec = current_ec;
 463                                 current_ec = ec;
 464                                 val = val.Resolve (ec);
 465                                 current_ec = old_ec;
 466
 467                                 in_transit.Remove (name);
 468                                 ec.InEnumContext = old;
 469
 470                                 if (val == null)
 471                                         return null;
 472
 473                                 if (!IsValidEnumConstant (val)) {
 474                                         Report.Error (
 475                                                 1008, loc,
 476                                                 "Type byte, sbyte, short, ushort, int, uint, long, or " +
 477                                                 "ulong expected (have: " + val + ")");
 478                                         return null;
 479                                 }
 480
 481                                 c = (Constant) val;
 482                                 default_value = c.GetValue ();
 483
 484                                 if (default_value == null) {
 485                                         Error_ConstantValueCannotBeConverted (c, loc);
 486                                         return null;
 487                                 }
 488
 489                                 if (val is EnumConstant){
 490                                         Type etype = TypeManager.EnumToUnderlying (c.Type);
 491
 492                                         if (!ImplicitConversionExists (etype, UnderlyingType)){
 493                                                 Expression.Error_CannotConvertImplicit (
 494                                                         loc, c.Type, UnderlyingType);
 495                                                 return null;
 496                                         }
 497                                 }
 498                         }
 499
 500                         FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static
 501                                         | FieldAttributes.Literal;
 502
 503                         FieldBuilder fb = TypeBuilder.DefineField (name, TypeBuilder, attr);
 504
 505                         bool fail;
 506                         default_value = TypeManager.ChangeType (default_value, UnderlyingType, out fail);
 507                         if (fail){
 508                                 Error_ConstantValueCannotBeConverted (c, loc);
 509                                 return null;
 510                         }
 511
 512                         fb.SetConstant (default_value);
 513                         field_builders.Add (fb);
 514                         member_to_value [name] = default_value;
 515
 516                         if (!TypeManager.RegisterFieldValue (fb, default_value))
 517                                 return null;
 518
 519                         //
 520                         // Now apply attributes
 521                         //
 522                         Attribute.ApplyAttributes (ec, fb, fb, (Attributes) member_to_attributes [name]);
 523
 524                         return default_value;
 525                 }
 526
 527                 public override bool DefineMembers (TypeContainer parent)
 528                 {
 529                         return true;
 530                 }
 531
 532                 public override bool Define (TypeContainer parent)
 533                 {
 534                         //
 535                         // If there was an error during DefineEnum, return
 536                         //
 537                         if (TypeBuilder == null)
 538                                 return false;
 539
 540                         EmitContext ec = new EmitContext (this, this, Location, null,
 541                                                           UnderlyingType, ModFlags, false);
 542
 543
 544                         object default_value = 0;
 545
 546                         FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static
 547                                              | FieldAttributes.Literal;
 548
 549
 550                         foreach (string name in ordered_enums) {
 551                                 //
 552                                 // Have we already been defined, thanks to some cross-referencing ?
 553                                 //
 554                                 if (member_to_value.Contains (name))
 555                                         continue;
 556
 557                                 Location loc = (Mono.CSharp.Location) member_to_location [name];
 558
 559                                 if (this [name] != null) {
 560                                         default_value = LookupEnumValue (ec, name, loc);
 561
 562                                         if (default_value == null)
 563                                                 return true;
 564                                 } else {
 565                                         if (name == "value__"){
 566                                                 Report.Error (76, loc, "The name `value__' is reserved for enumerations");
 567                                                 return false;
 568                                         }
 569
 570                                         FieldBuilder fb = TypeBuilder.DefineField (
 571                                                 name, TypeBuilder, attr);
 572
 573                                         if (default_value == null) {
 574                                            Report.Error (543, loc, "Enumerator value for '" + name + "' is too large to " +
 575                                                               "fit in its type");
 576                                                 return false;
 577                                         }
 578
 579                                         bool fail;
 580                                         default_value = TypeManager.ChangeType (default_value, UnderlyingType, out fail);
 581                                         if (fail){
 582                                                 Error_ConstantValueCannotBeConverted (default_value, loc);
 583                                                 return false;
 584                                         }
 585
 586                                         fb.SetConstant (default_value);
 587                                         field_builders.Add (fb);
 588                                         member_to_value [name] = default_value;
 589
 590                                         if (!TypeManager.RegisterFieldValue (fb, default_value))
 591                                                 return false;
 592
 593                                         //
 594                                         // Apply attributes on the enum member
 595                                         //
 596                                         Attribute.ApplyAttributes (ec, fb, fb, (Attributes) member_to_attributes [name]);
 597                                 }
 598
 599                                 default_value = GetNextDefaultValue (default_value);
 600                         }
 601
 602                         Attribute.ApplyAttributes (ec, TypeBuilder, this, OptAttributes);
 603
 604                         return true;
 605                 }
 606
 607                 //
 608                 // IMemberFinder
 609                 //
 610                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 611                                                         MemberFilter filter, object criteria)
 612                 {
 613                         ArrayList members = new ArrayList ();
 614
 615                         if ((mt & MemberTypes.Field) != 0) {
 616                                 if (criteria is string){
 617                                         if (member_to_value [criteria] == null && current_ec != null){
 618                                                 LookupEnumValue (current_ec, (string) criteria, Location.Null);
 619                                         }
 620                                 }
 621
 622                                 foreach (FieldBuilder fb in field_builders)
 623                                         if (filter (fb, criteria) == true)
 624                                                 members.Add (fb);
 625                         }
 626
 627                         return new MemberList (members);
 628                 }
 629
 630                 public override MemberCache MemberCache {
 631                         get {
 632                                 return null;
 633                         }
 634                 }
 635
 636                 public ArrayList ValueNames {
 637                         get {
 638                                 return ordered_enums;
 639                         }
 640                 }
 641
 642                 // indexer
 643                 public Expression this [string name] {
 644                         get {
 645                                 return (Expression) defined_names [name];
 646                         }
 647                 }
 648         }
 649 }