mcs/gmcs/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
  27                 public Type UnderlyingType;
  28
  29                 Hashtable member_to_location;
  30                 Hashtable member_to_attributes;
  31
  32                 //
  33                 // This is for members that have been defined
  34                 //
  35                 Hashtable member_to_value;
  36
  37                 //
  38                 // This is used to mark members we're currently defining
  39                 //
  40                 Hashtable in_transit;
  41
  42                 ArrayList field_builders;
  43
  44                 public const int AllowedModifiers =
  45                         Modifiers.NEW |
  46                         Modifiers.PUBLIC |
  47                         Modifiers.PROTECTED |
  48                         Modifiers.INTERNAL |
  49                         Modifiers.PRIVATE;
  50
  51                 public Enum (NamespaceEntry ns, TypeContainer parent, Expression type, int mod_flags,
  52                              string name, Attributes attrs, Location l)
  53                         : base (ns, parent, name, attrs, l)
  54                 {
  55                         this.BaseType = type;
  56                         ModFlags = Modifiers.Check (AllowedModifiers, mod_flags,
  57                                                     IsTopLevel ? Modifiers.INTERNAL : Modifiers.PRIVATE, l);
  58
  59                         ordered_enums = new ArrayList ();
  60                         member_to_location = new Hashtable ();
  61                         member_to_value = new Hashtable ();
  62                         in_transit = new Hashtable ();
  63                         field_builders = new ArrayList ();
  64                 }
  65
  66                 /// <summary>
  67                 ///   Adds @name to the enumeration space, with @expr
  68                 ///   being its definition.
  69                 /// </summary>
  70                 public AdditionResult AddEnumMember (string name, Expression expr, Location loc,
  71                                                      Attributes opt_attrs)
  72                 {
  73                         if (defined_names.Contains (name))
  74                                 return AdditionResult.NameExists;
  75
  76                         if (name == "value__") {
  77                                 Report.Error (76, loc, "An item in an enumeration can't have an identifier `value__'");
  78                                 return AdditionResult.Error;
  79                         }
  80
  81                         DefineName (name, expr);
  82
  83                         ordered_enums.Add (name);
  84                         member_to_location.Add (name, loc);
  85
  86                         if (member_to_attributes == null)
  87                                 member_to_attributes = new Hashtable ();
  88
  89                         member_to_attributes.Add (name, opt_attrs);
  90
  91                         return AdditionResult.Success;
  92                 }
  93
  94                 //
  95                 // This is used by corlib compilation: we map from our
  96                 // type to a type that is consumable by the DefineField
  97                 //
  98                 Type MapToInternalType (Type t)
  99                 {
 100                         if (t == TypeManager.int32_type)
 101                                 return typeof (int);
 102                         if (t == TypeManager.int64_type)
 103                                 return typeof (long);
 104                         if (t == TypeManager.uint32_type)
 105                                 return typeof (uint);
 106                         if (t == TypeManager.uint64_type)
 107                                 return typeof (ulong);
 108                         if (t == TypeManager.float_type)
 109                                 return typeof (float);
 110                         if (t == TypeManager.double_type)
 111                                 return typeof (double);
 112                         if (t == TypeManager.byte_type)
 113                                 return typeof (byte);
 114                         if (t == TypeManager.sbyte_type)
 115                                 return typeof (sbyte);
 116                         if (t == TypeManager.char_type)
 117                                 return typeof (char);
 118                         if (t == TypeManager.short_type)
 119                                 return typeof (short);
 120                         if (t == TypeManager.ushort_type)
 121                                 return typeof (ushort);
 122
 123                         throw new Exception ();
 124                 }
 125
 126                 public override TypeBuilder DefineType ()
 127                 {
 128                         if (TypeBuilder != null)
 129                                 return TypeBuilder;
 130
 131                         TypeAttributes attr = Modifiers.TypeAttr (ModFlags, IsTopLevel);
 132
 133                         attr |= TypeAttributes.Class | TypeAttributes.Sealed;
 134
 135                         UnderlyingType = ResolveType (BaseType, false, Location);
 136
 137                         if (UnderlyingType != TypeManager.int32_type &&
 138                             UnderlyingType != TypeManager.uint32_type &&
 139                             UnderlyingType != TypeManager.int64_type &&
 140                             UnderlyingType != TypeManager.uint64_type &&
 141                             UnderlyingType != TypeManager.short_type &&
 142                             UnderlyingType != TypeManager.ushort_type &&
 143                             UnderlyingType != TypeManager.byte_type  &&
 144                             UnderlyingType != TypeManager.char_type  &&
 145                             UnderlyingType != TypeManager.sbyte_type) {
 146                                 Report.Error (1008, Location,
 147                                               "Type byte, sbyte, short, char, ushort, int, uint, " +
 148                                               "long, or ulong expected (got: " +
 149                                               TypeManager.CSharpName (UnderlyingType) + ")");
 150                                 return null;
 151                         }
 152
 153                         if (IsTopLevel) {
 154                                 if (TypeManager.NamespaceClash (Name, Location))
 155                                         return null;
 156
 157                                 ModuleBuilder builder = CodeGen.Module.Builder;
 158
 159                                 TypeBuilder = builder.DefineType (Name, attr, TypeManager.enum_type);
 160                         } else {
 161                                 TypeBuilder builder = Parent.TypeBuilder;
 162
 163                                 TypeBuilder = builder.DefineNestedType (
 164                                         Basename, attr, TypeManager.enum_type);
 165                         }
 166
 167                         //
 168                         // Call MapToInternalType for corlib
 169                         //
 170                         TypeBuilder.DefineField ("value__", UnderlyingType,
 171                                                  FieldAttributes.Public | FieldAttributes.SpecialName
 172                                                  | FieldAttributes.RTSpecialName);
 173
 174                         TypeManager.AddEnumType (Name, TypeBuilder, this);
 175
 176                         return TypeBuilder;
 177                 }
 178
 179                 bool IsValidEnumConstant (Expression e)
 180                 {
 181                         if (!(e is Constant))
 182                                 return false;
 183
 184                         if (e is IntConstant || e is UIntConstant || e is LongConstant ||
 185                             e is ByteConstant || e is SByteConstant || e is ShortConstant ||
 186                             e is UShortConstant || e is ULongConstant || e is EnumConstant ||
 187                             e is CharConstant)
 188                                 return true;
 189                         else
 190                                 return false;
 191                 }
 192
 193                 object GetNextDefaultValue (object default_value)
 194                 {
 195                         if (UnderlyingType == TypeManager.int32_type) {
 196                                 int i = (int) default_value;
 197
 198                                 if (i < System.Int32.MaxValue)
 199                                         return ++i;
 200                                 else
 201                                         return null;
 202                         } else if (UnderlyingType == TypeManager.uint32_type) {
 203                                 uint i = (uint) default_value;
 204
 205                                 if (i < System.UInt32.MaxValue)
 206                                         return ++i;
 207                                 else
 208                                         return null;
 209                         } else if (UnderlyingType == TypeManager.int64_type) {
 210                                 long i = (long) default_value;
 211
 212                                 if (i < System.Int64.MaxValue)
 213                                         return ++i;
 214                                 else
 215                                         return null;
 216                         } else if (UnderlyingType == TypeManager.uint64_type) {
 217                                 ulong i = (ulong) default_value;
 218
 219                                 if (i < System.UInt64.MaxValue)
 220                                         return ++i;
 221                                 else
 222                                         return null;
 223                         } else if (UnderlyingType == TypeManager.short_type) {
 224                                 short i = (short) default_value;
 225
 226                                 if (i < System.Int16.MaxValue)
 227                                         return ++i;
 228                                 else
 229                                         return null;
 230                         } else if (UnderlyingType == TypeManager.ushort_type) {
 231                                 ushort i = (ushort) default_value;
 232
 233                                 if (i < System.UInt16.MaxValue)
 234                                         return ++i;
 235                                 else
 236                                         return null;
 237                         } else if (UnderlyingType == TypeManager.byte_type) {
 238                                 byte i = (byte) default_value;
 239
 240                                 if (i < System.Byte.MaxValue)
 241                                         return ++i;
 242                                 else
 243                                         return null;
 244                         } else if (UnderlyingType == TypeManager.sbyte_type) {
 245                                 sbyte i = (sbyte) default_value;
 246
 247                                 if (i < System.SByte.MaxValue)
 248                                         return ++i;
 249                                 else
 250                                         return null;
 251                         }
 252
 253                         return null;
 254                 }
 255
 256                 void Error_ConstantValueCannotBeConverted (object val, Location loc)
 257                 {
 258                         if (val is Constant)
 259                                 Report.Error (31, loc, "Constant value '" + ((Constant) val).AsString () +
 260                                               "' cannot be converted" +
 261                                               " to a " + TypeManager.CSharpName (UnderlyingType));
 262                         else
 263                                 Report.Error (31, loc, "Constant value '" + val +
 264                                               "' cannot be converted" +
 265                                               " to a " + TypeManager.CSharpName (UnderlyingType));
 266                         return;
 267                 }
 268
 269                 /// <summary>
 270                 ///  Determines if a standard implicit conversion exists from
 271                 ///  expr_type to target_type
 272                 /// </summary>
 273                 public static bool ImplicitConversionExists (Type expr_type, Type target_type)
 274                 {
 275                         expr_type = TypeManager.TypeToCoreType (expr_type);
 276
 277                         if (expr_type == TypeManager.void_type)
 278                                 return false;
 279
 280                         if (expr_type == target_type)
 281                                 return true;
 282
 283                         // First numeric conversions
 284
 285                         if (expr_type == TypeManager.sbyte_type){
 286                                 //
 287                                 // From sbyte to short, int, long, float, double.
 288                                 //
 289                                 if ((target_type == TypeManager.int32_type) ||
 290                                     (target_type == TypeManager.int64_type) ||
 291                                     (target_type == TypeManager.double_type) ||
 292                                     (target_type == TypeManager.float_type)  ||
 293                                     (target_type == TypeManager.short_type) ||
 294                                     (target_type == TypeManager.decimal_type))
 295                                         return true;
 296
 297                         } else if (expr_type == TypeManager.byte_type){
 298                                 //
 299                                 // From byte to short, ushort, int, uint, long, ulong, float, double
 300                                 //
 301                                 if ((target_type == TypeManager.short_type) ||
 302                                     (target_type == TypeManager.ushort_type) ||
 303                                     (target_type == TypeManager.int32_type) ||
 304                                     (target_type == TypeManager.uint32_type) ||
 305                                     (target_type == TypeManager.uint64_type) ||
 306                                     (target_type == TypeManager.int64_type) ||
 307                                     (target_type == TypeManager.float_type) ||
 308                                     (target_type == TypeManager.double_type) ||
 309                                     (target_type == TypeManager.decimal_type))
 310                                         return true;
 311
 312                         } else if (expr_type == TypeManager.short_type){
 313                                 //
 314                                 // From short to int, long, float, double
 315                                 //
 316                                 if ((target_type == TypeManager.int32_type) ||
 317                                     (target_type == TypeManager.int64_type) ||
 318                                     (target_type == TypeManager.double_type) ||
 319                                     (target_type == TypeManager.float_type) ||
 320                                     (target_type == TypeManager.decimal_type))
 321                                         return true;
 322
 323                         } else if (expr_type == TypeManager.ushort_type){
 324                                 //
 325                                 // From ushort to int, uint, long, ulong, float, double
 326                                 //
 327                                 if ((target_type == TypeManager.uint32_type) ||
 328                                     (target_type == TypeManager.uint64_type) ||
 329                                     (target_type == TypeManager.int32_type) ||
 330                                     (target_type == TypeManager.int64_type) ||
 331                                     (target_type == TypeManager.double_type) ||
 332                                     (target_type == TypeManager.float_type) ||
 333                                     (target_type == TypeManager.decimal_type))
 334                                         return true;
 335
 336                         } else if (expr_type == TypeManager.int32_type){
 337                                 //
 338                                 // From int to long, float, double
 339                                 //
 340                                 if ((target_type == TypeManager.int64_type) ||
 341                                     (target_type == TypeManager.double_type) ||
 342                                     (target_type == TypeManager.float_type) ||
 343                                     (target_type == TypeManager.decimal_type))
 344                                         return true;
 345
 346                         } else if (expr_type == TypeManager.uint32_type){
 347                                 //
 348                                 // From uint to long, ulong, float, double
 349                                 //
 350                                 if ((target_type == TypeManager.int64_type) ||
 351                                     (target_type == TypeManager.uint64_type) ||
 352                                     (target_type == TypeManager.double_type) ||
 353                                     (target_type == TypeManager.float_type) ||
 354                                     (target_type == TypeManager.decimal_type))
 355                                         return true;
 356
 357                         } else if ((expr_type == TypeManager.uint64_type) ||
 358                                    (expr_type == TypeManager.int64_type)) {
 359                                 //
 360                                 // From long/ulong to float, double
 361                                 //
 362                                 if ((target_type == TypeManager.double_type) ||
 363                                     (target_type == TypeManager.float_type) ||
 364                                     (target_type == TypeManager.decimal_type))
 365                                         return true;
 366
 367                         } else if (expr_type == TypeManager.char_type){
 368                                 //
 369                                 // From char to ushort, int, uint, long, ulong, float, double
 370                                 //
 371                                 if ((target_type == TypeManager.ushort_type) ||
 372                                     (target_type == TypeManager.int32_type) ||
 373                                     (target_type == TypeManager.uint32_type) ||
 374                                     (target_type == TypeManager.uint64_type) ||
 375                                     (target_type == TypeManager.int64_type) ||
 376                                     (target_type == TypeManager.float_type) ||
 377                                     (target_type == TypeManager.double_type) ||
 378                                     (target_type == TypeManager.decimal_type))
 379                                         return true;
 380
 381                         } else if (expr_type == TypeManager.float_type){
 382                                 //
 383                                 // float to double
 384                                 //
 385                                 if (target_type == TypeManager.double_type)
 386                                         return true;
 387                         }
 388
 389                         return false;
 390                 }
 391
 392                 //
 393                 // Horrible, horrible.  But there is no other way we can pass the EmitContext
 394                 // to the recursive definition triggered by the evaluation of a forward
 395                 // expression
 396                 //
 397                 static EmitContext current_ec = null;
 398
 399                 /// <summary>
 400                 ///  This is used to lookup the value of an enum member. If the member is undefined,
 401                 ///  it attempts to define it and return its value
 402                 /// </summary>
 403                 public object LookupEnumValue (EmitContext ec, string name, Location loc)
 404                 {
 405
 406                         object default_value = null;
 407                         Constant c = null;
 408
 409                         default_value = member_to_value [name];
 410
 411                         if (default_value != null)
 412                                 return default_value;
 413
 414                         //
 415                         // This may happen if we're calling a method in System.Enum, for instance
 416                         // Enum.IsDefined().
 417                         //
 418                         if (!defined_names.Contains (name))
 419                                 return null;
 420
 421                         if (in_transit.Contains (name)) {
 422                                 Report.Error (110, loc, "The evaluation of the constant value for `" +
 423                                               Name + "." + name + "' involves a circular definition.");
 424                                 return null;
 425                         }
 426
 427                         //
 428                         // So if the above doesn't happen, we have a member that is undefined
 429                         // We now proceed to define it
 430                         //
 431                         Expression val = this [name];
 432
 433                         if (val == null) {
 434
 435                                 int idx = ordered_enums.IndexOf (name);
 436
 437                                 if (idx == 0)
 438                                         default_value = 0;
 439                                 else {
 440                                         for (int i = 0; i < idx; ++i) {
 441                                                 string n = (string) ordered_enums [i];
 442                                                 Location m_loc = (Mono.CSharp.Location)
 443                                                         member_to_location [n];
 444                                                 in_transit.Add (name, true);
 445
 446                                                 EmitContext old_ec = current_ec;
 447                                                 current_ec = ec;
 448
 449                                                 default_value = LookupEnumValue (ec, n, m_loc);
 450
 451                                                 current_ec = old_ec;
 452
 453                                                 in_transit.Remove (name);
 454                                                 if (default_value == null)
 455                                                         return null;
 456                                         }
 457
 458                                         default_value = GetNextDefaultValue (default_value);
 459                                 }
 460
 461                         } else {
 462                                 bool old = ec.InEnumContext;
 463                                 ec.InEnumContext = true;
 464                                 in_transit.Add (name, true);
 465
 466                                 EmitContext old_ec = current_ec;
 467                                 current_ec = ec;
 468                                 val = val.Resolve (ec);
 469                                 current_ec = old_ec;
 470
 471                                 in_transit.Remove (name);
 472                                 ec.InEnumContext = old;
 473
 474                                 if (val == null)
 475                                         return null;
 476
 477                                 if (!IsValidEnumConstant (val)) {
 478                                         Report.Error (
 479                                                 1008, loc,
 480                                                 "Type byte, sbyte, short, ushort, int, uint, long, or " +
 481                                                 "ulong expected (have: " + val + ")");
 482                                         return null;
 483                                 }
 484
 485                                 c = (Constant) val;
 486                                 default_value = c.GetValue ();
 487
 488                                 if (default_value == null) {
 489                                         Error_ConstantValueCannotBeConverted (c, loc);
 490                                         return null;
 491                                 }
 492
 493                                 if (val is EnumConstant){
 494                                         Type etype = TypeManager.EnumToUnderlying (c.Type);
 495
 496                                         if (!ImplicitConversionExists (etype, UnderlyingType)){
 497                                                 Convert.Error_CannotImplicitConversion (
 498                                                         loc, c.Type, UnderlyingType);
 499                                                 return null;
 500                                         }
 501                                 }
 502                         }
 503
 504                         FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static
 505                                         | FieldAttributes.Literal;
 506
 507                         FieldBuilder fb = TypeBuilder.DefineField (name, TypeBuilder, attr);
 508
 509                         bool fail;
 510                         default_value = TypeManager.ChangeType (default_value, UnderlyingType, out fail);
 511                         if (fail){
 512                                 Error_ConstantValueCannotBeConverted (c, loc);
 513                                 return null;
 514                         }
 515
 516                         fb.SetConstant (default_value);
 517                         field_builders.Add (fb);
 518                         member_to_value [name] = default_value;
 519
 520                         if (!TypeManager.RegisterFieldValue (fb, default_value))
 521                                 return null;
 522
 523                         //
 524                         // Now apply attributes
 525                         //
 526                         Attribute.ApplyAttributes (ec, fb, fb, (Attributes) member_to_attributes [name]);
 527
 528                         return default_value;
 529                 }
 530
 531                 public override bool DefineMembers (TypeContainer parent)
 532                 {
 533                         return true;
 534                 }
 535
 536                 public override bool Define (TypeContainer parent)
 537                 {
 538                         //
 539                         // If there was an error during DefineEnum, return
 540                         //
 541                         if (TypeBuilder == null)
 542                                 return false;
 543
 544                         EmitContext ec = new EmitContext (this, this, Location, null,
 545                                                           UnderlyingType, ModFlags, false);
 546
 547
 548                         object default_value = 0;
 549
 550                         FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static
 551                                              | FieldAttributes.Literal;
 552
 553
 554                         foreach (string name in ordered_enums) {
 555                                 //
 556                                 // Have we already been defined, thanks to some cross-referencing ?
 557                                 //
 558                                 if (member_to_value.Contains (name))
 559                                         continue;
 560
 561                                 Location loc = (Mono.CSharp.Location) member_to_location [name];
 562
 563                                 if (this [name] != null) {
 564                                         default_value = LookupEnumValue (ec, name, loc);
 565
 566                                         if (default_value == null)
 567                                                 return true;
 568                                 } else {
 569                                         if (name == "value__"){
 570                                                 Report.Error (76, loc, "The name `value__' is reserved for enumerations");
 571                                                 return false;
 572                                         }
 573
 574                                         FieldBuilder fb = TypeBuilder.DefineField (
 575                                                 name, TypeBuilder, attr);
 576
 577                                         if (default_value == null) {
 578                                            Report.Error (543, loc, "Enumerator value for '" + name + "' is too large to " +
 579                                                               "fit in its type");
 580                                                 return false;
 581                                         }
 582
 583                                         bool fail;
 584                                         default_value = TypeManager.ChangeType (default_value, UnderlyingType, out fail);
 585                                         if (fail){
 586                                                 Error_ConstantValueCannotBeConverted (default_value, loc);
 587                                                 return false;
 588                                         }
 589
 590                                         fb.SetConstant (default_value);
 591                                         field_builders.Add (fb);
 592                                         member_to_value [name] = default_value;
 593
 594                                         if (!TypeManager.RegisterFieldValue (fb, default_value))
 595                                                 return false;
 596
 597                                         //
 598                                         // Apply attributes on the enum member
 599                                         //
 600                                         Attribute.ApplyAttributes (ec, fb, fb, (Attributes) member_to_attributes [name]);
 601                                 }
 602
 603                                 default_value = GetNextDefaultValue (default_value);
 604                         }
 605
 606                         Attribute.ApplyAttributes (ec, TypeBuilder, this, OptAttributes);
 607
 608                         return true;
 609                 }
 610
 611                 //
 612                 // IMemberFinder
 613                 //
 614                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 615                                                         MemberFilter filter, object criteria)
 616                 {
 617                         ArrayList members = new ArrayList ();
 618
 619                         if ((mt & MemberTypes.Field) != 0) {
 620                                 if (criteria is string){
 621                                         if (member_to_value [criteria] == null && current_ec != null){
 622                                                 LookupEnumValue (current_ec, (string) criteria, Location.Null);
 623                                         }
 624                                 }
 625
 626                                 foreach (FieldBuilder fb in field_builders)
 627                                         if (filter (fb, criteria) == true)
 628                                                 members.Add (fb);
 629                         }
 630
 631                         return new MemberList (members);
 632                 }
 633
 634                 public override MemberCache MemberCache {
 635                         get {
 636                                 return null;
 637                         }
 638                 }
 639
 640                 public ArrayList ValueNames {
 641                         get {
 642                                 return ordered_enums;
 643                         }
 644                 }
 645
 646                 // indexer
 647                 public Expression this [string name] {
 648                         get {
 649                                 return (Expression) defined_names [name];
 650                         }
 651                 }
 652         }
 653 }