Extensions.cs :  » 2.6.4-mono-.net-core » System.Linq » System » Linq » Expressions » C# / CSharp Open Source

//
// Extensions.cs
//
// Author:
//   Jb Evain (jbevain@novell.com)
//
// (C) 2008 Novell, Inc. (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons 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 FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;
using System.Reflection;
using System.Reflection.Emit;
using System.Runtime.CompilerServices;

namespace System.Linq.Expressions{

  static class Extensions {

    public static bool IsGenericInstanceOf (this Type self, Type type)
    {
      if (!self.IsGenericType)
        return false;

      return self.GetGenericTypeDefinition () == type;
    }

    public static bool IsNullable (this Type self)
    {
      return self.IsValueType && self.IsGenericInstanceOf (typeof (Nullable<>));
    }

    public static bool IsExpression (this Type self)
    {
      return self == typeof (Expression) || self.IsSubclassOf (typeof (Expression));
    }

    public static bool IsGenericImplementationOf (this Type self, Type type)
    {
      foreach (Type iface in self.GetInterfaces ())
        if (iface.IsGenericInstanceOf (type))
          return true;
      return false;
    }

    public static bool IsAssignableTo (this Type self, Type type)
    {
      return type.IsAssignableFrom (self) ||
        ArrayTypeIsAssignableTo (self, type);
    }

    public static Type GetFirstGenericArgument (this Type self)
    {
      return self.GetGenericArguments () [0];
    }

    public static Type MakeGenericTypeFrom (this Type self, Type type)
    {
      return self.MakeGenericType (type.GetGenericArguments ());
    }

    public static Type MakeNullableType (this Type self)
    {
      return typeof (Nullable<>).MakeGenericType (self);
    }

    public static Type GetNotNullableType (this Type self)
    {
      return self.IsNullable () ? self.GetFirstGenericArgument () : self;
    }

    public static MethodInfo GetInvokeMethod (this Type self)
    {
      return self.GetMethod ("Invoke", BindingFlags.Public | BindingFlags.Instance);
    }

    public static MethodInfo MakeGenericMethodFrom (this MethodInfo self, MethodInfo method)
    {
      return self.MakeGenericMethod (method.GetGenericArguments ());
    }

    public static Type [] GetParameterTypes (this MethodBase self)
    {
      var parameters = self.GetParameters ();
      var types = new Type [parameters.Length];

      for (int i = 0; i < types.Length; i++)
        types [i] = parameters [i].ParameterType;

      return types;
    }

    static bool ArrayTypeIsAssignableTo (Type type, Type candidate)
    {
      if (!type.IsArray || !candidate.IsArray)
        return false;

      if (type.GetArrayRank () != candidate.GetArrayRank ())
        return false;

      return type.GetElementType ().IsAssignableTo (candidate.GetElementType ());
    }

    public static void OnFieldOrProperty (this MemberInfo self,
      Action<FieldInfo> onfield, Action<PropertyInfo> onprop)
    {
      switch (self.MemberType) {
      case MemberTypes.Field:
        onfield ((FieldInfo) self);
        return;
      case MemberTypes.Property:
        onprop ((PropertyInfo) self);
        return;
      default:
        throw new ArgumentException ();
      }
    }

    public static T OnFieldOrProperty<T> (this MemberInfo self,
      Func<FieldInfo, T> onfield, Func<PropertyInfo, T> onprop)
    {
      switch (self.MemberType) {
      case MemberTypes.Field:
        return onfield ((FieldInfo) self);
      case MemberTypes.Property:
        return onprop ((PropertyInfo) self);
      default:
        throw new ArgumentException ();
      }
    }

    public static Type MakeStrongBoxType (this Type self)
    {
      return typeof (StrongBox<>).MakeGenericType (self);
    }
  }
}