HeuristicLab.PluginInfrastructure/3.3/TypeExtensions.cs

   1 #region License Information
   2
   3 /* HeuristicLab
   4  * Copyright (C) Heuristic and Evolutionary Algorithms Laboratory (HEAL)
   5  *
   6  * This file is part of HeuristicLab.
   7  *
   8  * HeuristicLab is free software: you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation, either version 3 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * HeuristicLab is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #endregion
  23
  24 using System;
  25 using System.Collections.Generic;
  26 using System.Linq;
  27 using System.Reflection;
  28
  29 namespace HeuristicLab.PluginInfrastructure {
  30   internal static class TypeExtensions {
  31     internal static bool IsNonDiscoverableType(this Type t) {
  32       return t.GetCustomAttributes(typeof(NonDiscoverableTypeAttribute), false).Any();
  33     }
  34
  35     /// <summary>
  36     /// Constructs a concrete type from a given proto type.
  37     /// </summary>
  38     /// <param name="type"></param>
  39     /// <param name="protoType"></param>
  40     /// <returns>The constructed type, a generic type definition or null, if a type construction is not possible</returns>
  41     /// <remarks>This method does not work with nested generic types</remarks>
  42     internal static Type BuildType(this Type type, Type protoType) {
  43       if (type == null || protoType == null) throw new ArgumentNullException();
  44
  45       if (!type.IsGenericTypeDefinition) return type;
  46       if (protoType.IsGenericTypeDefinition) return type;
  47       if (!protoType.IsGenericType) return type;
  48
  49       var typeGenericArguments = type.GetGenericArguments();
  50       var protoTypeGenericArguments = protoType.GetGenericArguments();
  51       if (typeGenericArguments.Length != protoTypeGenericArguments.Length) return null;
  52
  53       for (int i = 0; i < typeGenericArguments.Length; i++) {
  54         var typeGenericArgument = typeGenericArguments[i];
  55         var protoTypeGenericArgument = protoTypeGenericArguments[i];
  56
  57         //check class contraint on generic type parameter
  58         if (typeGenericArgument.GenericParameterAttributes.HasFlag(GenericParameterAttributes.ReferenceTypeConstraint))
  59           if (!protoTypeGenericArgument.IsClass && !protoTypeGenericArgument.IsInterface && !protoType.IsArray) return null;
  60
  61         //check default constructor constraint on generic type parameter
  62         if (typeGenericArgument.GenericParameterAttributes.HasFlag(GenericParameterAttributes.DefaultConstructorConstraint))
  63           if (!protoTypeGenericArgument.IsValueType && protoTypeGenericArgument.GetConstructor(Type.EmptyTypes) == null) return null;
  64
  65         //check type restrictions on generic type parameter
  66         foreach (var constraint in typeGenericArgument.GetGenericParameterConstraints())
  67           if (!constraint.IsAssignableFrom(protoTypeGenericArgument)) return null;
  68       }
  69
  70       try {
  71         return type.MakeGenericType(protoTypeGenericArguments);
  72       }
  73       catch (Exception) {
  74         return null;
  75       }
  76     }
  77
  78     internal static bool IsSubTypeOf(this Type subType, Type baseType) {
  79       if (baseType.IsAssignableFrom(subType)) return true;
  80       if (!baseType.IsGenericType) return false;
  81
  82       if (RecursiveCheckGenericTypes(baseType, subType)) return true;
  83       IEnumerable<Type> implementedInterfaces = subType.GetInterfaces().Where(t => t.IsGenericType);
  84       foreach (var implementedInterface in implementedInterfaces.Where(i => i.IsGenericType)) {
  85         if (baseType.CheckGenericTypes(implementedInterface)) return true;
  86       }
  87
  88       return false;
  89     }
  90
  91     private static bool RecursiveCheckGenericTypes(Type baseType, Type subType) {
  92       if (!baseType.IsGenericType) return false;
  93       if (!subType.IsGenericType) return false;
  94       if (baseType.CheckGenericTypes(subType)) return true;
  95       if (subType.BaseType == null) return false;
  96
  97       return RecursiveCheckGenericTypes(baseType, subType.BaseType);
  98     }
  99
 100     private static bool CheckGenericTypes(this Type baseType, Type subType) {
 101       var baseTypeGenericTypeDefinition = baseType.GetGenericTypeDefinition();
 102       var subTypeGenericTypeDefinition = subType.GetGenericTypeDefinition();
 103       if (baseTypeGenericTypeDefinition != subTypeGenericTypeDefinition) return false;
 104       var baseTypeGenericArguments = baseType.GetGenericArguments();
 105       var subTypeGenericArguments = subType.GetGenericArguments();
 106
 107       for (int i = 0; i < baseTypeGenericArguments.Length; i++) {
 108         var baseTypeGenericArgument = baseTypeGenericArguments[i];
 109         var subTypeGenericArgument = subTypeGenericArguments[i];
 110
 111         if (baseTypeGenericArgument.IsGenericParameter ^ subTypeGenericArgument.IsGenericParameter) return false;
 112         if (baseTypeGenericArgument == subTypeGenericArgument) continue;
 113         if (!baseTypeGenericArgument.IsGenericParameter && !subTypeGenericArgument.IsGenericParameter) return false;
 114
 115         if (baseTypeGenericArgument.GenericParameterAttributes.HasFlag(GenericParameterAttributes.ReferenceTypeConstraint) &&
 116             !subTypeGenericArgument.GenericParameterAttributes.HasFlag(GenericParameterAttributes.ReferenceTypeConstraint)) return false;
 117         if (baseTypeGenericArgument.GenericParameterAttributes.HasFlag(GenericParameterAttributes.DefaultConstructorConstraint) &&
 118             !subTypeGenericArgument.GenericParameterAttributes.HasFlag(GenericParameterAttributes.DefaultConstructorConstraint)) return false;
 119         if (baseTypeGenericArgument.GenericParameterAttributes.HasFlag(GenericParameterAttributes.NotNullableValueTypeConstraint) &&
 120             !subTypeGenericArgument.GenericParameterAttributes.HasFlag(GenericParameterAttributes.NotNullableValueTypeConstraint)) return false;
 121
 122         foreach (var baseTypeGenericParameterConstraint in baseTypeGenericArgument.GetGenericParameterConstraints()) {
 123           if (!subTypeGenericArgument.GetGenericParameterConstraints().Any(t => baseTypeGenericParameterConstraint.IsAssignableFrom(t))) return false;
 124         }
 125       }
 126       return true;
 127     }
 128   }
 129 }