mono/mcs/class/System.Web.Extensions/System.Web.Script.Serialization/JSON/ReflectionUtils.cs

#region License
// Copyright 2006 James Newton-King
// http://www.newtonsoft.com
//
// This work is licensed under the Creative Commons Attribution 2.5 License
// http://creativecommons.org/licenses/by/2.5/
//
// You are free:
//    * to copy, distribute, display, and perform the work
//    * to make derivative works
//    * to make commercial use of the work
//
// Under the following conditions:
//    * For any reuse or distribution, you must make clear to others the license terms of this work.
//    * Any of these conditions can be waived if you get permission from the copyright holder.
#endregion

using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using System.Collections;
using System.ComponentModel;

namespace Newtonsoft.Json.Utilities
{
    internal static class ReflectionUtils
    {
        public static bool IsInstantiatableType(Type t)
        {
            if (t == null)
                throw new ArgumentNullException("t");

            if (t.IsAbstract || t.IsInterface || t.IsArray)
                return false;

            if (!HasDefaultConstructor(t))
                return false;

            return true;
        }

        public static bool HasDefaultConstructor(Type t)
        {
            if (t == null)
                throw new ArgumentNullException("t");

            return (t.GetConstructor(BindingFlags.Instance, null, Type.EmptyTypes, null) != null);
        }

		public static bool IsAssignable (Type to, Type from) {
			if (to == null)
				throw new ArgumentNullException("to");

			if (to.IsAssignableFrom (from))
				return true;

			if (to.IsGenericType && from.IsGenericTypeDefinition)
				return to.IsAssignableFrom (from.MakeGenericType (to.GetGenericArguments ()));

			return false;
		}

        public static bool IsSubClass(Type type, Type check)
        {
            if (type == null || check == null)
                return false;

            if (type == check)
                return true;

            if (check.IsInterface)
            {
                foreach (Type t in type.GetInterfaces())
                {
                    if (IsSubClass(t, check)) return true;
                }
            }
            if (type.IsGenericType && !type.IsGenericTypeDefinition)
            {
                if (IsSubClass(type.GetGenericTypeDefinition(), check))
                    return true;
            }
            return IsSubClass(type.BaseType, check);
        }

        /// <summary>
        /// Gets the type of the typed list's items.
        /// </summary>
        /// <param name="type">The type.</param>
        /// <returns>The type of the typed list's items.</returns>
        public static Type GetTypedListItemType(Type type)
        {
            if (type == null)
                throw new ArgumentNullException("type");

			if (type.IsArray)
				return type.GetElementType ();
			else if (type.IsGenericType && typeof (List<>).IsAssignableFrom (type.GetGenericTypeDefinition ()))
				return type.GetGenericArguments () [0];
			else
				throw new Exception ("Bad type");
        }

        public static Type GetTypedDictionaryValueType(Type type)
        {
            if (type == null)
                throw new ArgumentNullException("type");

			Type genDictType = GetGenericDictionary(type);

			if (genDictType != null)
				return genDictType.GetGenericArguments () [1];
            else if (typeof(IDictionary).IsAssignableFrom(type))
                return null;
            else
                throw new Exception("Bad type");
        }

		static readonly Type GenericDictionaryType = typeof (IDictionary<,>);
		public static Type GetGenericDictionary (Type type) {
			if (type.IsGenericType && GenericDictionaryType.IsAssignableFrom (type.GetGenericTypeDefinition ()))
				return type;

			Type[] ifaces = type.GetInterfaces();
			if (ifaces != null)
				for (int i = 0; i < ifaces.Length; i++) {
					Type current = GetGenericDictionary (ifaces [i]);
					if (current != null)
						return current;
				}

			return null;
		}

        public static Type GetMemberUnderlyingType(MemberInfo member)
        {
            switch (member.MemberType)
            {
                case MemberTypes.Field:
                    return ((FieldInfo)member).FieldType;
                case MemberTypes.Property:
                    return ((PropertyInfo)member).PropertyType;
                case MemberTypes.Event:
                    return ((EventInfo)member).EventHandlerType;
                default:
                    throw new ArgumentException("MemberInfo must be if type FieldInfo, PropertyInfo or EventInfo", "member");
            }
        }

        /// <summary>
        /// Determines whether the member is an indexed property.
        /// </summary>
        /// <param name="member">The member.</param>
        /// <returns>
        /// 	<c>true</c> if the member is an indexed property; otherwise, <c>false</c>.
        /// </returns>
        public static bool IsIndexedProperty(MemberInfo member)
        {
            if (member == null)
                throw new ArgumentNullException("member");

            PropertyInfo propertyInfo = member as PropertyInfo;

            if (propertyInfo != null)
                return IsIndexedProperty(propertyInfo);
            else
                return false;
        }

        /// <summary>
        /// Determines whether the property is an indexed property.
        /// </summary>
        /// <param name="property">The property.</param>
        /// <returns>
        /// 	<c>true</c> if the property is an indexed property; otherwise, <c>false</c>.
        /// </returns>
        public static bool IsIndexedProperty(PropertyInfo property)
        {
            if (property == null)
                throw new ArgumentNullException("property");

            return (property.GetIndexParameters().Length > 0);
        }

        /// <summary>
        /// Gets the member's value on the object.
        /// </summary>
        /// <param name="member">The member.</param>
        /// <param name="target">The target object.</param>
        /// <returns>The member's value on the object.</returns>
        public static object GetMemberValue(MemberInfo member, object target)
        {
            switch (member.MemberType)
            {
                case MemberTypes.Field:
                    return ((FieldInfo)member).GetValue(target);
                case MemberTypes.Property:
                    try
                    {
                        return ((PropertyInfo)member).GetValue(target, null);
                    }
                    catch (TargetParameterCountException e)
                    {
                        throw new ArgumentException("MemberInfo has index parameters", "member", e);
                    }
                default:
                    throw new ArgumentException("MemberInfo is not of type FieldInfo or PropertyInfo", "member");
            }
        }

        /// <summary>
        /// Sets the member's value on the target object.
        /// </summary>
        /// <param name="member">The member.</param>
        /// <param name="target">The target.</param>
        /// <param name="value">The value.</param>
        public static void SetMemberValue(MemberInfo member, object target, object value)
        {
            switch (member.MemberType)
            {
                case MemberTypes.Field:
                    ((FieldInfo)member).SetValue(target, value);
                    break;
                case MemberTypes.Property:
                    ((PropertyInfo)member).SetValue(target, value, null);
                    break;
                default:
                    throw new ArgumentException("MemberInfo must be if type FieldInfo or PropertyInfo", "member");
            }
        }

		/// <summary>
		/// Determines whether the specified MemberInfo can be read.
		/// </summary>
		/// <param name="member">The MemberInfo to determine whether can be read.</param>
		/// <returns>
		/// 	<c>true</c> if the specified MemberInfo can be read; otherwise, <c>false</c>.
		/// </returns>
		public static bool CanReadMemberValue(MemberInfo member)
		{
			switch (member.MemberType)
			{
				case MemberTypes.Field:
					return true;
				case MemberTypes.Property:
					return ((PropertyInfo) member).CanRead;
				default:
					return false;
			}
		}

        /// <summary>
        /// Determines whether the specified MemberInfo can be set.
        /// </summary>
        /// <param name="member">The MemberInfo to determine whether can be set.</param>
        /// <returns>
        /// 	<c>true</c> if the specified MemberInfo can be set; otherwise, <c>false</c>.
        /// </returns>
        public static bool CanSetMemberValue(MemberInfo member)
        {
            switch (member.MemberType)
            {
                case MemberTypes.Field:
                    return true;
                case MemberTypes.Property:
                    return ((PropertyInfo)member).CanWrite;
                default:
                    return false;
            }
        }

		public static IEnumerable<MemberInfo> GetFieldsAndProperties (Type type, BindingFlags bindingAttr) {

			MemberInfo [] members = type.GetFields (bindingAttr);
			for (int i = 0; i < members.Length; i++)
				yield return members [i];
			members = type.GetProperties (bindingAttr);
			for (int i = 0; i < members.Length; i++)
				yield return members [i];
		}
    }
}