source: branches/CodeEditor/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.CSharp-5.5.0/TypeSystem/MethodTypeParameterWithInheritedConstraints.cs @ 11700

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// 
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// software and associated documentation files (the "Software"), to deal in the Software
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// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
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using System;
using System.Collections.Generic;
using System.Linq;
using ICSharpCode.NRefactory.TypeSystem;
using ICSharpCode.NRefactory.TypeSystem.Implementation;
using ICSharpCode.NRefactory.Utils;

namespace ICSharpCode.NRefactory.CSharp.TypeSystem
{
  [Serializable]
  public sealed class MethodTypeParameterWithInheritedConstraints : DefaultUnresolvedTypeParameter
  {
    public MethodTypeParameterWithInheritedConstraints(int index, string name)
      : base(SymbolKind.Method, index, name)
    {
    }
    
    static ITypeParameter ResolveBaseTypeParameter(IMethod parentMethod, int index)
    {
      IMethod baseMethod = null;
      if (parentMethod.IsOverride) {
        foreach (IMethod m in InheritanceHelper.GetBaseMembers(parentMethod, false).OfType<IMethod>()) {
          if (!m.IsOverride) {
            baseMethod = m;
            break;
          }
        }
      } else if (parentMethod.IsExplicitInterfaceImplementation && parentMethod.ImplementedInterfaceMembers.Count == 1) {
        baseMethod = parentMethod.ImplementedInterfaceMembers[0] as IMethod;
      }
      if (baseMethod != null && index < baseMethod.TypeParameters.Count)
        return baseMethod.TypeParameters[index];
      else
        return null;
    }
    
    public override ITypeParameter CreateResolvedTypeParameter(ITypeResolveContext context)
    {
      if (context.CurrentMember is IMethod) {
        return new ResolvedMethodTypeParameterWithInheritedConstraints(this, context);
      } else {
        return base.CreateResolvedTypeParameter(context);
      }
    }
    
    sealed class ResolvedMethodTypeParameterWithInheritedConstraints : AbstractTypeParameter
    {
      volatile ITypeParameter baseTypeParameter;
      
      public ResolvedMethodTypeParameterWithInheritedConstraints(MethodTypeParameterWithInheritedConstraints unresolved, ITypeResolveContext context)
        : base(context.CurrentMember, unresolved.Index, unresolved.Name, unresolved.Variance,
               unresolved.Attributes.CreateResolvedAttributes(context), unresolved.Region)
      {
      }
      
      ITypeParameter GetBaseTypeParameter()
      {
        ITypeParameter baseTP = this.baseTypeParameter;
        if (baseTP == null) {
          // ResolveBaseTypeParameter() is idempotent, so this is thread-safe.
          this.baseTypeParameter = baseTP = ResolveBaseTypeParameter((IMethod)this.Owner, this.Index);
        }
        return baseTP;
      }
      
      public override bool HasValueTypeConstraint {
        get {
          ITypeParameter baseTP = GetBaseTypeParameter();
          return baseTP != null ? baseTP.HasValueTypeConstraint : false;
        }
      }
      
      public override bool HasReferenceTypeConstraint {
        get {
          ITypeParameter baseTP = GetBaseTypeParameter();
          return baseTP != null ? baseTP.HasReferenceTypeConstraint : false;
        }
      }
      
      public override bool HasDefaultConstructorConstraint {
        get {
          ITypeParameter baseTP = GetBaseTypeParameter();
          return baseTP != null ? baseTP.HasDefaultConstructorConstraint : false;
        }
      }
      
      public override IEnumerable<IType> DirectBaseTypes {
        get {
          ITypeParameter baseTP = GetBaseTypeParameter();
          if (baseTP != null) {
            // Substitute occurrences of the base method's type parameters in the constraints
            // with the type parameters from the
            IMethod owner = (IMethod)this.Owner;
            var substitution = new TypeParameterSubstitution(null, new ProjectedList<ITypeParameter, IType>(owner.TypeParameters, t => t));
            return baseTP.DirectBaseTypes.Select(t => t.AcceptVisitor(substitution));
          } else {
            return EmptyList<IType>.Instance;
          }
        }
      }
    }
  }
}