System.Xml.Serialization.XmlSchemaImporter.ImportAttribute C# (CSharp) Method

        private AttributeAccessor ImportAttribute(XmlSchemaAttribute attribute, string identifier, string ns, XmlSchemaAttribute defaultValueProvider)
        {
            if (attribute.Use == XmlSchemaUse.Prohibited) return null;
            if (!attribute.RefName.IsEmpty)
            {
                if (attribute.RefName.Namespace == XmlReservedNs.NsXml)
                    return ImportSpecialAttribute(attribute.RefName, identifier);
                else
                    return ImportAttribute(FindAttribute(attribute.RefName), identifier, attribute.RefName.Namespace, defaultValueProvider);
            }
            TypeMapping mapping;
            if (attribute.Name.Length == 0) throw new InvalidOperationException(SR.XmlAttributeHasNoName);
            if (identifier.Length == 0)
                identifier = CodeIdentifier.MakeValid(attribute.Name);
            else
                identifier += CodeIdentifier.MakePascal(attribute.Name);
            if (!attribute.SchemaTypeName.IsEmpty)
                mapping = (TypeMapping)ImportType(attribute.SchemaTypeName, typeof(TypeMapping), null, TypeFlags.CanBeAttributeValue, false);
            else if (attribute.SchemaType != null)
                mapping = ImportDataType((XmlSchemaSimpleType)attribute.SchemaType, ns, identifier, null, TypeFlags.CanBeAttributeValue, false);
            else
            {
                mapping = GetDefaultMapping(TypeFlags.CanBeAttributeValue);
            }

            // let the extensions to run
            if (mapping != null && !mapping.TypeDesc.IsMappedType)
            {
                RunSchemaExtensions(mapping, attribute.SchemaTypeName, attribute.SchemaType, attribute, TypeFlags.CanBeElementValue | TypeFlags.CanBeAttributeValue | TypeFlags.CanBeTextValue);
            }
            AttributeAccessor accessor = new AttributeAccessor();
            accessor.Name = attribute.Name;
            accessor.Namespace = ns;
            accessor.Form = AttributeForm(ns, attribute);
            accessor.CheckSpecial();
            accessor.Mapping = mapping;
            accessor.IsList = mapping.IsList;
            accessor.IsOptional = attribute.Use != XmlSchemaUse.Required;

            if (defaultValueProvider.DefaultValue != null)
            {
                accessor.Default = defaultValueProvider.DefaultValue;
            }
            else if (defaultValueProvider.FixedValue != null)
            {
                accessor.Default = defaultValueProvider.FixedValue;
                accessor.IsFixed = true;
            }
            else if (attribute != defaultValueProvider)
            {
                if (attribute.DefaultValue != null)
                {
                    accessor.Default = attribute.DefaultValue;
                }
                else if (attribute.FixedValue != null)
                {
                    accessor.Default = attribute.FixedValue;
                    accessor.IsFixed = true;
                }
            }
            return accessor;
        }