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.sbyte_type) {
 141                                 Report.Error (1008, Location,
 142                                               "Type byte, sbyte, short, ushort, int, uint, " +
 143                                               "long, or ulong expected (got: " +
 144                                               TypeManager.CSharpName (UnderlyingType) + ")");
 145                                 return null;
 146                         }
 147
 148                         if (IsTopLevel) {
 149                                 ModuleBuilder builder = CodeGen.ModuleBuilder;
 150
 151                                 TypeBuilder = builder.DefineType (Name, attr, TypeManager.enum_type);
 152                         } else {
 153                                 TypeBuilder builder = Parent.TypeBuilder;
 154
 155                                 TypeBuilder = builder.DefineNestedType (
 156                                         Basename, attr, TypeManager.enum_type);
 157                         }
 158
 159                         //
 160                         // Call MapToInternalType for corlib
 161                         //
 162                         TypeBuilder.DefineField ("value__", UnderlyingType,
 163                                                  FieldAttributes.Public | FieldAttributes.SpecialName
 164                                                  | FieldAttributes.RTSpecialName);
 165
 166                         TypeManager.AddEnumType (Name, TypeBuilder, this);
 167
 168                         return TypeBuilder;
 169                 }
 170
 171                 bool IsValidEnumConstant (Expression e)
 172                 {
 173                         if (!(e is Constant))
 174                                 return false;
 175
 176                         if (e is IntConstant || e is UIntConstant || e is LongConstant ||
 177                             e is ByteConstant || e is SByteConstant || e is ShortConstant ||
 178                             e is UShortConstant || e is ULongConstant || e is EnumConstant)
 179                                 return true;
 180                         else
 181                                 return false;
 182                 }
 183
 184                 object GetNextDefaultValue (object default_value)
 185                 {
 186                         if (UnderlyingType == TypeManager.int32_type) {
 187                                 int i = (int) default_value;
 188
 189                                 if (i < System.Int32.MaxValue)
 190                                         return ++i;
 191                                 else
 192                                         return null;
 193                         } else if (UnderlyingType == TypeManager.uint32_type) {
 194                                 uint i = (uint) default_value;
 195
 196                                 if (i < System.UInt32.MaxValue)
 197                                         return ++i;
 198                                 else
 199                                         return null;
 200                         } else if (UnderlyingType == TypeManager.int64_type) {
 201                                 long i = (long) default_value;
 202
 203                                 if (i < System.Int64.MaxValue)
 204                                         return ++i;
 205                                 else
 206                                         return null;
 207                         } else if (UnderlyingType == TypeManager.uint64_type) {
 208                                 ulong i = (ulong) default_value;
 209
 210                                 if (i < System.UInt64.MaxValue)
 211                                         return ++i;
 212                                 else
 213                                         return null;
 214                         } else if (UnderlyingType == TypeManager.short_type) {
 215                                 short i = (short) default_value;
 216
 217                                 if (i < System.Int16.MaxValue)
 218                                         return ++i;
 219                                 else
 220                                         return null;
 221                         } else if (UnderlyingType == TypeManager.ushort_type) {
 222                                 ushort i = (ushort) default_value;
 223
 224                                 if (i < System.UInt16.MaxValue)
 225                                         return ++i;
 226                                 else
 227                                         return null;
 228                         } else if (UnderlyingType == TypeManager.byte_type) {
 229                                 byte i = (byte) default_value;
 230
 231                                 if (i < System.Byte.MaxValue)
 232                                         return ++i;
 233                                 else
 234                                         return null;
 235                         } else if (UnderlyingType == TypeManager.sbyte_type) {
 236                                 sbyte i = (sbyte) default_value;
 237
 238                                 if (i < System.SByte.MaxValue)
 239                                         return ++i;
 240                                 else
 241                                         return null;
 242                         }
 243
 244                         return null;
 245                 }
 246
 247                 void Error_ConstantValueCannotBeConverted (object val, Location loc)
 248                 {
 249                         if (val is Constant)
 250                                 Report.Error (31, loc, "Constant value '" + ((Constant) val).AsString () +
 251                                               "' cannot be converted" +
 252                                               " to a " + TypeManager.CSharpName (UnderlyingType));
 253                         else
 254                                 Report.Error (31, loc, "Constant value '" + val +
 255                                               "' cannot be converted" +
 256                                               " to a " + TypeManager.CSharpName (UnderlyingType));
 257                         return;
 258                 }
 259
 260                 /// <summary>
 261                 ///  Determines if a standard implicit conversion exists from
 262                 ///  expr_type to target_type
 263                 /// </summary>
 264                 public static bool ImplicitConversionExists (Type expr_type, Type target_type)
 265                 {
 266                         expr_type = TypeManager.TypeToCoreType (expr_type);
 267
 268                         if (expr_type == TypeManager.void_type)
 269                                 return false;
 270
 271                         if (expr_type == target_type)
 272                                 return true;
 273
 274                         // First numeric conversions
 275
 276                         if (expr_type == TypeManager.sbyte_type){
 277                                 //
 278                                 // From sbyte to short, int, long, float, double.
 279                                 //
 280                                 if ((target_type == TypeManager.int32_type) ||
 281                                     (target_type == TypeManager.int64_type) ||
 282                                     (target_type == TypeManager.double_type) ||
 283                                     (target_type == TypeManager.float_type)  ||
 284                                     (target_type == TypeManager.short_type) ||
 285                                     (target_type == TypeManager.decimal_type))
 286                                         return true;
 287
 288                         } else if (expr_type == TypeManager.byte_type){
 289                                 //
 290                                 // From byte to short, ushort, int, uint, long, ulong, float, double
 291                                 //
 292                                 if ((target_type == TypeManager.short_type) ||
 293                                     (target_type == TypeManager.ushort_type) ||
 294                                     (target_type == TypeManager.int32_type) ||
 295                                     (target_type == TypeManager.uint32_type) ||
 296                                     (target_type == TypeManager.uint64_type) ||
 297                                     (target_type == TypeManager.int64_type) ||
 298                                     (target_type == TypeManager.float_type) ||
 299                                     (target_type == TypeManager.double_type) ||
 300                                     (target_type == TypeManager.decimal_type))
 301                                         return true;
 302
 303                         } else if (expr_type == TypeManager.short_type){
 304                                 //
 305                                 // From short to int, long, float, double
 306                                 //
 307                                 if ((target_type == TypeManager.int32_type) ||
 308                                     (target_type == TypeManager.int64_type) ||
 309                                     (target_type == TypeManager.double_type) ||
 310                                     (target_type == TypeManager.float_type) ||
 311                                     (target_type == TypeManager.decimal_type))
 312                                         return true;
 313
 314                         } else if (expr_type == TypeManager.ushort_type){
 315                                 //
 316                                 // From ushort to int, uint, long, ulong, float, double
 317                                 //
 318                                 if ((target_type == TypeManager.uint32_type) ||
 319                                     (target_type == TypeManager.uint64_type) ||
 320                                     (target_type == TypeManager.int32_type) ||
 321                                     (target_type == TypeManager.int64_type) ||
 322                                     (target_type == TypeManager.double_type) ||
 323                                     (target_type == TypeManager.float_type) ||
 324                                     (target_type == TypeManager.decimal_type))
 325                                         return true;
 326
 327                         } else if (expr_type == TypeManager.int32_type){
 328                                 //
 329                                 // From int to long, float, double
 330                                 //
 331                                 if ((target_type == TypeManager.int64_type) ||
 332                                     (target_type == TypeManager.double_type) ||
 333                                     (target_type == TypeManager.float_type) ||
 334                                     (target_type == TypeManager.decimal_type))
 335                                         return true;
 336
 337                         } else if (expr_type == TypeManager.uint32_type){
 338                                 //
 339                                 // From uint to long, ulong, float, double
 340                                 //
 341                                 if ((target_type == TypeManager.int64_type) ||
 342                                     (target_type == TypeManager.uint64_type) ||
 343                                     (target_type == TypeManager.double_type) ||
 344                                     (target_type == TypeManager.float_type) ||
 345                                     (target_type == TypeManager.decimal_type))
 346                                         return true;
 347
 348                         } else if ((expr_type == TypeManager.uint64_type) ||
 349                                    (expr_type == TypeManager.int64_type)) {
 350                                 //
 351                                 // From long/ulong to float, double
 352                                 //
 353                                 if ((target_type == TypeManager.double_type) ||
 354                                     (target_type == TypeManager.float_type) ||
 355                                     (target_type == TypeManager.decimal_type))
 356                                         return true;
 357
 358                         } else if (expr_type == TypeManager.char_type){
 359                                 //
 360                                 // From char to ushort, int, uint, long, ulong, float, double
 361                                 //
 362                                 if ((target_type == TypeManager.ushort_type) ||
 363                                     (target_type == TypeManager.int32_type) ||
 364                                     (target_type == TypeManager.uint32_type) ||
 365                                     (target_type == TypeManager.uint64_type) ||
 366                                     (target_type == TypeManager.int64_type) ||
 367                                     (target_type == TypeManager.float_type) ||
 368                                     (target_type == TypeManager.double_type) ||
 369                                     (target_type == TypeManager.decimal_type))
 370                                         return true;
 371
 372                         } else if (expr_type == TypeManager.float_type){
 373                                 //
 374                                 // float to double
 375                                 //
 376                                 if (target_type == TypeManager.double_type)
 377                                         return true;
 378                         }
 379
 380                         return false;
 381                 }
 382
 383                 //
 384                 // Horrible, horrible.  But there is no other way we can pass the EmitContext
 385                 // to the recursive definition triggered by the evaluation of a forward
 386                 // expression
 387                 //
 388                 static EmitContext current_ec = null;
 389
 390                 /// <summary>
 391                 ///  This is used to lookup the value of an enum member. If the member is undefined,
 392                 ///  it attempts to define it and return its value
 393                 /// </summary>
 394                 public object LookupEnumValue (EmitContext ec, string name, Location loc)
 395                 {
 396
 397                         object default_value = null;
 398                         Constant c = null;
 399
 400                         default_value = member_to_value [name];
 401
 402                         if (default_value != null)
 403                                 return default_value;
 404
 405                         //
 406                         // This may happen if we're calling a method in System.Enum, for instance
 407                         // Enum.IsDefined().
 408                         //
 409                         if (!defined_names.Contains (name))
 410                                 return null;
 411
 412                         if (in_transit.Contains (name)) {
 413                                 Report.Error (110, loc, "The evaluation of the constant value for `" +
 414                                               Name + "." + name + "' involves a circular definition.");
 415                                 return null;
 416                         }
 417
 418                         //
 419                         // So if the above doesn't happen, we have a member that is undefined
 420                         // We now proceed to define it
 421                         //
 422                         Expression val = this [name];
 423
 424                         if (val == null) {
 425
 426                                 int idx = ordered_enums.IndexOf (name);
 427
 428                                 if (idx == 0)
 429                                         default_value = 0;
 430                                 else {
 431                                         for (int i = 0; i < idx; ++i) {
 432                                                 string n = (string) ordered_enums [i];
 433                                                 Location m_loc = (Mono.CSharp.Location)
 434                                                         member_to_location [n];
 435                                                 in_transit.Add (name, true);
 436
 437                                                 EmitContext old_ec = current_ec;
 438                                                 current_ec = ec;
 439
 440                                                 default_value = LookupEnumValue (ec, n, m_loc);
 441
 442                                                 current_ec = old_ec;
 443
 444                                                 in_transit.Remove (name);
 445                                                 if (default_value == null)
 446                                                         return null;
 447                                         }
 448
 449                                         default_value = GetNextDefaultValue (default_value);
 450                                 }
 451
 452                         } else {
 453                                 bool old = ec.InEnumContext;
 454                                 ec.InEnumContext = true;
 455                                 in_transit.Add (name, true);
 456
 457                                 EmitContext old_ec = current_ec;
 458                                 current_ec = ec;
 459                                 val = val.Resolve (ec);
 460                                 current_ec = old_ec;
 461
 462                                 in_transit.Remove (name);
 463                                 ec.InEnumContext = old;
 464
 465                                 if (val == null)
 466                                         return null;
 467
 468                                 if (!IsValidEnumConstant (val)) {
 469                                         Report.Error (
 470                                                 1008, loc,
 471                                                 "Type byte, sbyte, short, ushort, int, uint, long, or " +
 472                                                 "ulong expected (have: " + val + ")");
 473                                         return null;
 474                                 }
 475
 476                                 c = (Constant) val;
 477                                 default_value = c.GetValue ();
 478
 479                                 if (default_value == null) {
 480                                         Error_ConstantValueCannotBeConverted (c, loc);
 481                                         return null;
 482                                 }
 483
 484                                 if (val is EnumConstant){
 485                                         Type etype = TypeManager.EnumToUnderlying (c.Type);
 486
 487                                         if (!ImplicitConversionExists (etype, UnderlyingType)){
 488                                                 Expression.Error_CannotConvertImplicit (
 489                                                         loc, c.Type, UnderlyingType);
 490                                                 return null;
 491                                         }
 492                                 }
 493                         }
 494
 495                         FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static
 496                                         | FieldAttributes.Literal;
 497
 498                         FieldBuilder fb = TypeBuilder.DefineField (name, TypeBuilder, attr);
 499
 500                         bool fail;
 501                         default_value = TypeManager.ChangeType (default_value, UnderlyingType, out fail);
 502                         if (fail){
 503                                 Error_ConstantValueCannotBeConverted (c, loc);
 504                                 return null;
 505                         }
 506
 507                         fb.SetConstant (default_value);
 508                         field_builders.Add (fb);
 509                         member_to_value [name] = default_value;
 510
 511                         if (!TypeManager.RegisterFieldValue (fb, default_value))
 512                                 return null;
 513
 514                         //
 515                         // Now apply attributes
 516                         //
 517                         Attribute.ApplyAttributes (ec, fb, fb, (Attributes) member_to_attributes [name]);
 518
 519                         return default_value;
 520                 }
 521
 522                 public override bool DefineMembers (TypeContainer parent)
 523                 {
 524                         return true;
 525                 }
 526
 527                 public override bool Define (TypeContainer parent)
 528                 {
 529                         //
 530                         // If there was an error during DefineEnum, return
 531                         //
 532                         if (TypeBuilder == null)
 533                                 return false;
 534
 535                         EmitContext ec = new EmitContext (this, this, Location, null,
 536                                                           UnderlyingType, ModFlags, false);
 537
 538
 539                         object default_value = 0;
 540
 541                         FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static
 542                                              | FieldAttributes.Literal;
 543
 544
 545                         foreach (string name in ordered_enums) {
 546                                 //
 547                                 // Have we already been defined, thanks to some cross-referencing ?
 548                                 //
 549                                 if (member_to_value.Contains (name))
 550                                         continue;
 551
 552                                 Location loc = (Mono.CSharp.Location) member_to_location [name];
 553
 554                                 if (this [name] != null) {
 555                                         default_value = LookupEnumValue (ec, name, loc);
 556
 557                                         if (default_value == null)
 558                                                 return true;
 559                                 } else {
 560                                         if (name == "value__"){
 561                                                 Report.Error (76, loc, "The name `value__' is reserved for enumerations");
 562                                                 return false;
 563                                         }
 564
 565                                         FieldBuilder fb = TypeBuilder.DefineField (
 566                                                 name, TypeBuilder, attr);
 567
 568                                         if (default_value == null) {
 569                                            Report.Error (543, loc, "Enumerator value for '" + name + "' is too large to " +
 570                                                               "fit in its type");
 571                                                 return false;
 572                                         }
 573
 574                                         bool fail;
 575                                         default_value = TypeManager.ChangeType (default_value, UnderlyingType, out fail);
 576                                         if (fail){
 577                                                 Error_ConstantValueCannotBeConverted (default_value, loc);
 578                                                 return false;
 579                                         }
 580
 581                                         fb.SetConstant (default_value);
 582                                         field_builders.Add (fb);
 583                                         member_to_value [name] = default_value;
 584
 585                                         if (!TypeManager.RegisterFieldValue (fb, default_value))
 586                                                 return false;
 587
 588                                         //
 589                                         // Apply attributes on the enum member
 590                                         //
 591                                         Attribute.ApplyAttributes (ec, fb, fb, (Attributes) member_to_attributes [name]);
 592                                 }
 593
 594                                 default_value = GetNextDefaultValue (default_value);
 595                         }
 596
 597                         Attribute.ApplyAttributes (ec, TypeBuilder, this, OptAttributes);
 598
 599                         return true;
 600                 }
 601
 602                 //
 603                 // IMemberFinder
 604                 //
 605                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 606                                                         MemberFilter filter, object criteria)
 607                 {
 608                         ArrayList members = new ArrayList ();
 609
 610                         if ((mt & MemberTypes.Field) != 0) {
 611                                 if (criteria is string){
 612                                         if (member_to_value [criteria] == null && current_ec != null){
 613                                                 LookupEnumValue (current_ec, (string) criteria, Location.Null);
 614                                         }
 615                                 }
 616
 617                                 foreach (FieldBuilder fb in field_builders)
 618                                         if (filter (fb, criteria) == true)
 619                                                 members.Add (fb);
 620                         }
 621
 622                         return new MemberList (members);
 623                 }
 624
 625                 public override MemberCache MemberCache {
 626                         get {
 627                                 return null;
 628                         }
 629                 }
 630
 631                 public ArrayList ValueNames {
 632                         get {
 633                                 return ordered_enums;
 634                         }
 635                 }
 636
 637                 // indexer
 638                 public Expression this [string name] {
 639                         get {
 640                                 return (Expression) defined_names [name];
 641                         }
 642                 }
 643         }
 644 }