InstanceDescriptor.cs

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using System.Collections;
using System.Reflection;
 
namespace System.ComponentModel.Design.Serialization;
 
public sealed class InstanceDescriptor
{
    public ICollection Arguments { get; }
 
    public bool IsComplete { get; }
 
    public MemberInfo? MemberInfo { get; }
 
    public InstanceDescriptor(MemberInfo? member, ICollection? arguments)
        : this(member, arguments, isComplete: true)
    {
    }
 
    public InstanceDescriptor(MemberInfo? member, ICollection? arguments, bool isComplete)
    {
        MemberInfo = member;
        IsComplete = isComplete;
        if (arguments == null)
        {
            Arguments = Array.Empty<object>();
        }
        else
        {
            object[] array = new object[arguments.Count];
            arguments.CopyTo(array, 0);
            Arguments = array;
        }
        if (member is FieldInfo fieldInfo)
        {
            if (!fieldInfo.IsStatic)
            {
                throw new ArgumentException(System.SR.InstanceDescriptorMustBeStatic);
            }
            if (Arguments.Count != 0)
            {
                throw new ArgumentException(System.SR.InstanceDescriptorLengthMismatch);
            }
        }
        else if (member is ConstructorInfo constructorInfo)
        {
            if (constructorInfo.IsStatic)
            {
                throw new ArgumentException(System.SR.InstanceDescriptorCannotBeStatic);
            }
            if (Arguments.Count != constructorInfo.GetParameters().Length)
            {
                throw new ArgumentException(System.SR.InstanceDescriptorLengthMismatch);
            }
        }
        else if (member is MethodInfo methodInfo)
        {
            if (!methodInfo.IsStatic)
            {
                throw new ArgumentException(System.SR.InstanceDescriptorMustBeStatic);
            }
            if (Arguments.Count != methodInfo.GetParameters().Length)
            {
                throw new ArgumentException(System.SR.InstanceDescriptorLengthMismatch);
            }
        }
        else if (member is PropertyInfo propertyInfo)
        {
            if (!propertyInfo.CanRead)
            {
                throw new ArgumentException(System.SR.InstanceDescriptorMustBeReadable);
            }
            MethodInfo getMethod = propertyInfo.GetGetMethod();
            if (getMethod != null && !getMethod.IsStatic)
            {
                throw new ArgumentException(System.SR.InstanceDescriptorMustBeStatic);
            }
        }
    }
 
    public object? Invoke()
    {
        object[] array = new object[Arguments.Count];
        Arguments.CopyTo(array, 0);
        for (int i = 0; i < array.Length; i++)
        {
            if (array[i] is InstanceDescriptor instanceDescriptor)
            {
                array[i] = instanceDescriptor.Invoke();
            }
        }
        if (MemberInfo is ConstructorInfo)
        {
            return ((ConstructorInfo)MemberInfo).Invoke(array);
        }
        if (MemberInfo is MethodInfo)
        {
            return ((MethodInfo)MemberInfo).Invoke(null, array);
        }
        if (MemberInfo is PropertyInfo)
        {
            return ((PropertyInfo)MemberInfo).GetValue(null, array);
        }
        if (MemberInfo is FieldInfo)
        {
            return ((FieldInfo)MemberInfo).GetValue(null);
        }
        return null;
    }
}