mcs/mbas/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                 ///  This is used to lookup the value of an enum member. If the member is undefined,
 262                 ///  it attempts to define it and return its value
 263                 /// </summary>
 264                 public object LookupEnumValue (EmitContext ec, string name, Location loc)
 265                 {
 266                         object default_value = null;
 267                         Constant c = null;
 268
 269                         default_value = member_to_value [name];
 270
 271                         if (default_value != null)
 272                                 return default_value;
 273
 274                         //
 275                         // This may happen if we're calling a method in System.Enum, for instance
 276                         // Enum.IsDefined().
 277                         //
 278                         if (!defined_names.Contains (name))
 279                                 return null;
 280
 281                         if (in_transit.Contains (name)) {
 282                                 Report.Error (110, loc, "The evaluation of the constant value for `" +
 283                                               Name + "." + name + "' involves a circular definition.");
 284                                 return null;
 285                         }
 286
 287                         //
 288                         // So if the above doesn't happen, we have a member that is undefined
 289                         // We now proceed to define it
 290                         //
 291                         Expression val = this [name];
 292
 293                         if (val == null) {
 294
 295                                 int idx = ordered_enums.IndexOf (name);
 296
 297                                 if (idx == 0)
 298                                         default_value = 0;
 299                                 else {
 300                                         for (int i = 0; i < idx; ++i) {
 301                                                 string n = (string) ordered_enums [i];
 302                                                 Location m_loc = (Mono.CSharp.Location)
 303                                                         member_to_location [n];
 304                                                 in_transit.Add (name, true);
 305                                                 default_value = LookupEnumValue (ec, n, m_loc);
 306                                                 in_transit.Remove (name);
 307                                                 if (default_value == null)
 308                                                         return null;
 309                                         }
 310
 311                                         default_value = GetNextDefaultValue (default_value);
 312                                 }
 313
 314                         } else {
 315                                 bool old = ec.InEnumContext;
 316                                 ec.InEnumContext = true;
 317                                 in_transit.Add (name, true);
 318                                 val = val.Resolve (ec);
 319                                 in_transit.Remove (name);
 320                                 ec.InEnumContext = old;
 321
 322                                 if (val == null)
 323                                         return null;
 324
 325                                 if (IsValidEnumConstant (val)) {
 326                                         c = (Constant) val;
 327                                         default_value = c.GetValue ();
 328
 329                                         if (default_value == null) {
 330                                                 Error_ConstantValueCannotBeConverted (c, loc);
 331                                                 return null;
 332                                         }
 333
 334                                 } else {
 335                                         Report.Error (
 336                                                 1008, loc,
 337                                                 "Type byte, sbyte, short, ushort, int, uint, long, or " +
 338                                                 "ulong expected (have: " + val + ")");
 339                                         return null;
 340                                 }
 341                         }
 342
 343                         FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static
 344                                         | FieldAttributes.Literal;
 345
 346                         FieldBuilder fb = TypeBuilder.DefineField (name, UnderlyingType, attr);
 347
 348                         try {
 349                                 default_value = TypeManager.ChangeType (default_value, UnderlyingType);
 350                         } catch {
 351                                 Error_ConstantValueCannotBeConverted (c, loc);
 352                                 return null;
 353                         }
 354
 355                         fb.SetConstant (default_value);
 356                         field_builders.Add (fb);
 357                         member_to_value [name] = default_value;
 358
 359                         if (!TypeManager.RegisterFieldValue (fb, default_value))
 360                                 return null;
 361
 362                         //
 363                         // Now apply attributes
 364                         //
 365                         Attribute.ApplyAttributes (ec, fb, fb, (Attributes) member_to_attributes [name], loc);
 366
 367                         return default_value;
 368                 }
 369
 370                 public override bool Define (TypeContainer parent)
 371                 {
 372                         //
 373                         // If there was an error during DefineEnum, return
 374                         //
 375                         if (TypeBuilder == null)
 376                                 return false;
 377
 378                         EmitContext ec = new EmitContext (parent, this, Location, null,
 379                                                           UnderlyingType, ModFlags, false);
 380
 381                         object default_value = 0;
 382
 383                         FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static
 384                                              | FieldAttributes.Literal;
 385
 386
 387                         foreach (string name in ordered_enums) {
 388                                 //
 389                                 // Have we already been defined, thanks to some cross-referencing ?
 390                                 //
 391                                 if (member_to_value.Contains (name))
 392                                         continue;
 393
 394                                 Location loc = (Mono.CSharp.Location) member_to_location [name];
 395
 396                                 if (this [name] != null) {
 397                                         default_value = LookupEnumValue (ec, name, loc);
 398
 399                                         if (default_value == null)
 400                                                 return true;
 401
 402                                 } else {
 403                                         FieldBuilder fb = TypeBuilder.DefineField (
 404                                                 name, UnderlyingType, attr);
 405
 406                                         if (default_value == null) {
 407                                            Report.Error (543, loc, "Enumerator value for '" + name + "' is too large to " +
 408                                                               "fit in its type");
 409                                                 return false;
 410                                         }
 411
 412                                         try {
 413                                                 default_value = TypeManager.ChangeType (default_value, UnderlyingType);
 414                                         } catch {
 415                                                 Error_ConstantValueCannotBeConverted (default_value, loc);
 416                                                 return false;
 417                                         }
 418
 419                                         fb.SetConstant (default_value);
 420                                         field_builders.Add (fb);
 421                                         member_to_value [name] = default_value;
 422
 423                                         if (!TypeManager.RegisterFieldValue (fb, default_value))
 424                                                 return false;
 425
 426                                         //
 427                                         // Apply attributes on the enum member
 428                                         //
 429                                         Attribute.ApplyAttributes (ec, fb, fb, (Attributes) member_to_attributes [name], loc);
 430                                 }
 431
 432                                 default_value = GetNextDefaultValue (default_value);
 433                         }
 434
 435                         Attribute.ApplyAttributes (ec, TypeBuilder, this, OptAttributes, Location);
 436
 437                         return true;
 438                 }
 439
 440                 //
 441                 // Hack around System.Reflection as found everywhere else
 442                 //
 443                 public MemberInfo [] FindMembers (MemberTypes mt, BindingFlags bf,
 444                                                   MemberFilter filter, object criteria)
 445                 {
 446                         ArrayList members = new ArrayList ();
 447
 448                         if ((mt & MemberTypes.Field) != 0) {
 449                                 foreach (FieldBuilder fb in field_builders)
 450                                         if (filter (fb, criteria) == true)
 451                                                 members.Add (fb);
 452                         }
 453
 454                         int count = members.Count;
 455
 456                         if (count > 0) {
 457                                 MemberInfo [] mi = new MemberInfo [count];
 458                                 members.CopyTo (mi, 0);
 459                                 return mi;
 460                         }
 461
 462                         return null;
 463                 }
 464
 465                 public ArrayList ValueNames {
 466                         get {
 467                                 return ordered_enums;
 468                         }
 469                 }
 470
 471                 // indexer
 472                 public Expression this [string name] {
 473                         get {
 474                                 return (Expression) defined_names [name];
 475                         }
 476                 }
 477         }
 478 }