class Nokogiri::XML::Schema

def validate_document document
  errors = []
  ctx = LibXML.xmlSchemaNewValidCtxt(cstruct)
  raise RuntimeError.new("Could not create a validation context") if ctx.null?
  LibXML.xmlSchemaSetValidStructuredErrors(ctx,
    SyntaxError.error_array_pusher(errors), nil) unless Nokogiri.is_2_6_16?
  LibXML.xmlSchemaValidateDoc(ctx, document.cstruct)
  LibXML.xmlSchemaFreeValidCtxt(ctx)
  errors
end