/Dependencies/boo/src/Boo.Lang.Compiler/TypeSystem/ExternalGenericParameter.cs

#region license
// Copyright (c) 2003, 2004, 2005 Rodrigo B. de Oliveira (rbo@acm.org)
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
// 
//     * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//     * Neither the name of Rodrigo B. de Oliveira nor the names of its
//     contributors may be used to endorse or promote products derived from this
//     software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#endregion

using System;
using System.Reflection;
using Boo.Lang.Compiler;

namespace Boo.Lang.Compiler.TypeSystem
{
	public class ExternalGenericParameter : ExternalType, IGenericParameter
	{
		IMethod _declaringMethod = null;
		
		public ExternalGenericParameter(TypeSystemServices tss, Type type) : base(tss, type)
		{
			if (type.DeclaringMethod != null)
			{
				_declaringMethod = (IMethod)tss.Map(type.DeclaringMethod);
			}
		}
		
		public int GenericParameterPosition
		{
			get { return ActualType.GenericParameterPosition; }
		}
		
		public override string FullName 
		{
			get 
			{
				IEntity declaringEntity = 
					(DeclaringMethod == null ? (IEntity)DeclaringType : (IEntity)DeclaringMethod);
					
				return string.Format("{0}.{1}", declaringEntity.FullName, Name);
			}
		}
		
		public IMethod DeclaringMethod
		{
			get 
			{
				return _declaringMethod;
			}
		}

		public Variance Variance
		{
			get
			{
				GenericParameterAttributes variance = ActualType.GenericParameterAttributes & GenericParameterAttributes.VarianceMask;
				switch (variance)
				{
					case GenericParameterAttributes.None:
						return Variance.Invariant;

					case GenericParameterAttributes.Covariant:
						return Variance.Covariant;

					case GenericParameterAttributes.Contravariant:
						return Variance.Contravariant;

					default:
						return Variance.Invariant;
				}
			}
		}

		public IType[] GetBaseTypeConstraints()
		{
			return Array.ConvertAll<Type, IType>(
				ActualType.GetGenericParameterConstraints(), 
				_typeSystemServices.Map);
		}

		public bool MustHaveDefaultConstructor
		{
			get
			{
				return (ActualType.GenericParameterAttributes & GenericParameterAttributes.DefaultConstructorConstraint) == GenericParameterAttributes.DefaultConstructorConstraint;
			}
		}

		public override bool IsClass
		{
			get
			{
				return (ActualType.GenericParameterAttributes & GenericParameterAttributes.ReferenceTypeConstraint) == GenericParameterAttributes.ReferenceTypeConstraint;
			}
		}

		public override bool IsValueType
		{
			get
			{
				return (ActualType.GenericParameterAttributes & GenericParameterAttributes.NotNullableValueTypeConstraint) == GenericParameterAttributes.NotNullableValueTypeConstraint;
			}
		}

		override public bool Equals(object rhs)
		{
			IGenericParameter p = rhs as IGenericParameter;
			if (null == p) return false;

			//TODO: >=0.9 : check base type constraints
			return Name == p.Name //FIXME: should be GenericParameterPosition but crashes on internal g. params(?!!)
				&& Variance == p.Variance
				&& MustHaveDefaultConstructor  == p.MustHaveDefaultConstructor
				&& IsClass == p.IsClass
				&& IsValueType == p.IsValueType;
		}

		override public int GetHashCode()
		{
			return base.GetHashCode();
		}

	}

}