MarshalAsAttribute.cs

using System.Reflection;
using System.Security;

namespace System.Runtime.InteropServices
{
    [AttributeUsage(AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.ReturnValue, Inherited = false)]
    [ComVisible(true)]
    [__DynamicallyInvokable]
    public sealed class MarshalAsAttribute : Attribute
    {
        internal UnmanagedType _val;

        [__DynamicallyInvokable]
        public VarEnum SafeArraySubType;

        [__DynamicallyInvokable]
        public Type SafeArrayUserDefinedSubType;

        [__DynamicallyInvokable]
        public int IidParameterIndex;

        [__DynamicallyInvokable]
        public UnmanagedType ArraySubType;

        [__DynamicallyInvokable]
        public short SizeParamIndex;

        [__DynamicallyInvokable]
        public int SizeConst;

        [ComVisible(true)]
        [__DynamicallyInvokable]
        public string MarshalType;

        [ComVisible(true)]
        [__DynamicallyInvokable]
        public Type MarshalTypeRef;

        [__DynamicallyInvokable]
        public string MarshalCookie;

        [__DynamicallyInvokable]
        public UnmanagedType Value
        {
            [__DynamicallyInvokable]
            get
            {
                return _val;
            }
        }

        [SecurityCritical]
        internal static Attribute GetCustomAttribute(RuntimeParameterInfo parameter)
        {
            return GetCustomAttribute(parameter.MetadataToken, parameter.GetRuntimeModule());
        }

        [SecurityCritical]
        internal static bool IsDefined(RuntimeParameterInfo parameter)
        {
            return GetCustomAttribute(parameter) != null;
        }

        [SecurityCritical]
        internal static Attribute GetCustomAttribute(RuntimeFieldInfo field)
        {
            return GetCustomAttribute(field.MetadataToken, field.GetRuntimeModule());
        }

        [SecurityCritical]
        internal static bool IsDefined(RuntimeFieldInfo field)
        {
            return GetCustomAttribute(field) != null;
        }

        [SecurityCritical]
        internal static Attribute GetCustomAttribute(int token, RuntimeModule scope)
        {
            int sizeParamIndex = 0;
            int sizeConst = 0;
            string marshalType = null;
            string marshalCookie = null;
            string safeArrayUserDefinedSubType = null;
            int iidParamIndex = 0;
            ConstArray fieldMarshal = ModuleHandle.GetMetadataImport(scope.GetNativeHandle()).GetFieldMarshal(token);
            if (fieldMarshal.Length == 0)
            {
                return null;
            }
            MetadataImport.GetMarshalAs(fieldMarshal, out UnmanagedType unmanagedType, out VarEnum safeArraySubType, out safeArrayUserDefinedSubType, out UnmanagedType arraySubType, out sizeParamIndex, out sizeConst, out marshalType, out marshalCookie, out iidParamIndex);
            RuntimeType safeArrayUserDefinedSubType2 = (safeArrayUserDefinedSubType == null || safeArrayUserDefinedSubType.Length == 0) ? null : RuntimeTypeHandle.GetTypeByNameUsingCARules(safeArrayUserDefinedSubType, scope);
            RuntimeType marshalTypeRef = null;
            try
            {
                marshalTypeRef = ((marshalType == null) ? null : RuntimeTypeHandle.GetTypeByNameUsingCARules(marshalType, scope));
            }
            catch (TypeLoadException)
            {
            }
            return new MarshalAsAttribute(unmanagedType, safeArraySubType, safeArrayUserDefinedSubType2, arraySubType, (short)sizeParamIndex, sizeConst, marshalType, marshalTypeRef, marshalCookie, iidParamIndex);
        }

        internal MarshalAsAttribute(UnmanagedType val, VarEnum safeArraySubType, RuntimeType safeArrayUserDefinedSubType, UnmanagedType arraySubType, short sizeParamIndex, int sizeConst, string marshalType, RuntimeType marshalTypeRef, string marshalCookie, int iidParamIndex)
        {
            _val = val;
            SafeArraySubType = safeArraySubType;
            SafeArrayUserDefinedSubType = safeArrayUserDefinedSubType;
            IidParameterIndex = iidParamIndex;
            ArraySubType = arraySubType;
            SizeParamIndex = sizeParamIndex;
            SizeConst = sizeConst;
            MarshalType = marshalType;
            MarshalTypeRef = marshalTypeRef;
            MarshalCookie = marshalCookie;
        }

        [__DynamicallyInvokable]
        public MarshalAsAttribute(UnmanagedType unmanagedType)
        {
            _val = unmanagedType;
        }

        [__DynamicallyInvokable]
        public MarshalAsAttribute(short unmanagedType)
        {
            _val = (UnmanagedType)unmanagedType;
        }
    }
}