source: branches/2389-EpsLexicase/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.CSharp-5.5.0/Parser/mcs/enum.cs

//
// enum.cs: Enum handling.
//
// Author: Miguel de Icaza (miguel@gnu.org)
//         Ravi Pratap     (ravi@ximian.com)
//         Marek Safar     (marek.safar@seznam.cz)
//
// Dual licensed under the terms of the MIT X11 or GNU GPL
//
// Copyright 2001 Ximian, Inc (http://www.ximian.com)
// Copyright 2003-2003 Novell, Inc (http://www.novell.com)
// Copyright 2011 Xamarin Inc
//

using System;

#if STATIC
using MetaType = IKVM.Reflection.Type;
using IKVM.Reflection;
#else
using MetaType = System.Type;
using System.Reflection;
#endif

namespace Mono.CSharp {

  public class EnumMember : Const
  {
    class EnumTypeExpr : TypeExpr
    {
      public override TypeSpec ResolveAsType (IMemberContext ec, bool allowUnboundTypeArguments)
      {
        type = ec.CurrentType;
        eclass = ExprClass.Type;
        return type;
      }
    }

    public EnumMember (Enum parent, MemberName name, Attributes attrs)
      : base (parent, new EnumTypeExpr (), Modifiers.PUBLIC, name, attrs)
    {
    }

    static bool IsValidEnumType (TypeSpec t)
    {
      switch (t.BuiltinType) {
      case BuiltinTypeSpec.Type.Int:
      case BuiltinTypeSpec.Type.UInt:
      case BuiltinTypeSpec.Type.Long:
      case BuiltinTypeSpec.Type.Byte:
      case BuiltinTypeSpec.Type.SByte:
      case BuiltinTypeSpec.Type.Short:
      case BuiltinTypeSpec.Type.UShort:
      case BuiltinTypeSpec.Type.ULong:
      case BuiltinTypeSpec.Type.Char:
        return true;
      default:
        return t.IsEnum;
      }
    }

    public override Constant ConvertInitializer (ResolveContext rc, Constant expr)
    {
      if (expr is EnumConstant)
        expr = ((EnumConstant) expr).Child;

      var en = (Enum)Parent;
      var underlying = en.UnderlyingType;
      if (expr != null) {
        expr = expr.ImplicitConversionRequired (rc, underlying);
        if (expr != null && !IsValidEnumType (expr.Type)) {
          en.Error_UnderlyingType (Location);
          expr = null;
        }
      }

      if (expr == null)
        expr = New.Constantify (underlying, Location);

      return new EnumConstant (expr, MemberType);
    }

    public override bool Define ()
    {
      if (!ResolveMemberType ())
        return false;

      const FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static | FieldAttributes.Literal;
      FieldBuilder = Parent.TypeBuilder.DefineField (Name, MemberType.GetMetaInfo (), attr);
      spec = new ConstSpec (Parent.Definition, this, MemberType, FieldBuilder, ModFlags, initializer);

      Parent.MemberCache.AddMember (spec);
      return true;
    }
    
    public override void Accept (StructuralVisitor visitor)
    {
      visitor.Visit (this);
    }

  }

  /// <summary>
  ///   Enumeration container
  /// </summary>
  public class Enum : TypeDefinition
  {
    //
    // Implicit enum member initializer, used when no constant value is provided
    //
    sealed class ImplicitInitializer : Expression
    {
      readonly EnumMember prev;
      readonly EnumMember current;

      public ImplicitInitializer (EnumMember current, EnumMember prev)
      {
        this.current = current;
        this.prev = prev;
      }

      public override bool ContainsEmitWithAwait ()
      {
        return false;
      }

      public override Expression CreateExpressionTree (ResolveContext ec)
      {
        throw new NotSupportedException ("Missing Resolve call");
      }

      protected override Expression DoResolve (ResolveContext rc)
      {
        // We are the first member
        if (prev == null) {
          return New.Constantify (current.Parent.Definition, Location);
        }

        var c = ((ConstSpec) prev.Spec).GetConstant (rc) as EnumConstant;
        try {
          return c.Increment ();
        } catch (OverflowException) {
          rc.Report.Error (543, current.Location,
            "The enumerator value `{0}' is outside the range of enumerator underlying type `{1}'",
            current.GetSignatureForError (), ((Enum) current.Parent).UnderlyingType.GetSignatureForError ());

          return New.Constantify (current.Parent.Definition, current.Location);
        }
      }

      public override void Emit (EmitContext ec)
      {
        throw new NotSupportedException ("Missing Resolve call");
      }
    }

    public static readonly string UnderlyingValueField = "value__";

    const Modifiers AllowedModifiers =
      Modifiers.NEW |
      Modifiers.PUBLIC |
      Modifiers.PROTECTED |
      Modifiers.INTERNAL |
      Modifiers.PRIVATE;

    readonly FullNamedExpression underlying_type_expr;

    public Enum (TypeContainer parent, FullNamedExpression type, Modifiers mod_flags, MemberName name, Attributes attrs)
      : base (parent, name, attrs, MemberKind.Enum)
    {
      underlying_type_expr = type;
      var accmods = IsTopLevel ? Modifiers.INTERNAL : Modifiers.PRIVATE;
      ModFlags = ModifiersExtensions.Check (AllowedModifiers, mod_flags, accmods, Location, Report);
      spec = new EnumSpec (null, this, null, null, ModFlags);
    }

    #region Properties

    public override AttributeTargets AttributeTargets {
      get {
        return AttributeTargets.Enum;
      }
    }

    public FullNamedExpression BaseTypeExpression {
      get {
        return underlying_type_expr;
      }
    }

    protected override TypeAttributes TypeAttr {
      get {
        return base.TypeAttr | TypeAttributes.Class | TypeAttributes.Sealed;
      }
    }

    public TypeSpec UnderlyingType {
      get {
        return ((EnumSpec) spec).UnderlyingType;
      }
    }

    #endregion

    public override void Accept (StructuralVisitor visitor)
    {
      visitor.Visit (this);
    }

    public void AddEnumMember (EnumMember em)
    {
      if (em.Name == UnderlyingValueField) {
        Report.Error (76, em.Location, "An item in an enumeration cannot have an identifier `{0}'",
          UnderlyingValueField);
        return;
      }

      AddMember (em);
    }

    public void Error_UnderlyingType (Location loc)
    {
      Report.Error (1008, loc,
        "Type byte, sbyte, short, ushort, int, uint, long or ulong expected");
    }

    protected override void DoDefineContainer ()
    {
      TypeSpec ut;
      if (underlying_type_expr != null) {
        ut = underlying_type_expr.ResolveAsType (this);
        if (!EnumSpec.IsValidUnderlyingType (ut)) {
          Error_UnderlyingType (underlying_type_expr.Location);
          ut = null;
        }
      } else {
        ut = null;
      }

      if (ut == null)
        ut = Compiler.BuiltinTypes.Int;

      ((EnumSpec) spec).UnderlyingType = ut;

      TypeBuilder.DefineField (UnderlyingValueField, UnderlyingType.GetMetaInfo (),
        FieldAttributes.Public | FieldAttributes.SpecialName | FieldAttributes.RTSpecialName);

      DefineBaseTypes ();
    }

    protected override bool DoDefineMembers ()
    {
      for (int i = 0; i < Members.Count; ++i) {
        EnumMember em = (EnumMember) Members[i];
        if (em.Initializer == null) {
          em.Initializer = new ImplicitInitializer (em, i == 0 ? null : (EnumMember) Members[i - 1]);
        }

        em.Define ();
      }

      return true;
    }

    public override bool IsUnmanagedType ()
    {
      return true;
    }

    protected override TypeSpec[] ResolveBaseTypes (out FullNamedExpression base_class)
    {
      base_type = Compiler.BuiltinTypes.Enum;
      base_class = null;
      return null;
    }
    
    protected override bool VerifyClsCompliance ()
    {
      if (!base.VerifyClsCompliance ())
        return false;

      switch (UnderlyingType.BuiltinType) {
      case BuiltinTypeSpec.Type.UInt:
      case BuiltinTypeSpec.Type.ULong:
      case BuiltinTypeSpec.Type.UShort:
        Report.Warning (3009, 1, Location, "`{0}': base type `{1}' is not CLS-compliant",
          GetSignatureForError (), UnderlyingType.GetSignatureForError ());
        break;
      }

      return true;
    }
  }

  class EnumSpec : TypeSpec
  {
    TypeSpec underlying;

    public EnumSpec (TypeSpec declaringType, ITypeDefinition definition, TypeSpec underlyingType, MetaType info, Modifiers modifiers)
      : base (MemberKind.Enum, declaringType, definition, info, modifiers | Modifiers.SEALED)
    {
      this.underlying = underlyingType;
    }

    public TypeSpec UnderlyingType {
      get {
        return underlying;
      }
      set {
        if (underlying != null)
          throw new InternalErrorException ("UnderlyingType reset");

        underlying = value;
      }
    }

    public static TypeSpec GetUnderlyingType (TypeSpec t)
    {
      return ((EnumSpec) t.GetDefinition ()).UnderlyingType;
    }

    public static bool IsValidUnderlyingType (TypeSpec type)
    {
      switch (type.BuiltinType) {
      case BuiltinTypeSpec.Type.Int:
      case BuiltinTypeSpec.Type.UInt:
      case BuiltinTypeSpec.Type.Long:
      case BuiltinTypeSpec.Type.Byte:
      case BuiltinTypeSpec.Type.SByte:
      case BuiltinTypeSpec.Type.Short:
      case BuiltinTypeSpec.Type.UShort:
      case BuiltinTypeSpec.Type.ULong:
        return true;
      }

      return false;
    }
  }
}