/*
 * call-seq:
 *  validate_document(document)
 *
 * Validate a Nokogiri::XML::Document against this Schema.
 */
static VALUE validate_document(VALUE self, VALUE document)
{
  xmlDocPtr doc;
  xmlSchemaPtr schema;
  xmlSchemaValidCtxtPtr valid_ctxt;
  VALUE errors;

  Data_Get_Struct(self, xmlSchema, schema);
  Data_Get_Struct(document, xmlDoc, doc);

  errors = rb_ary_new();

  valid_ctxt = xmlSchemaNewValidCtxt(schema);

  if(NULL == valid_ctxt) {
    /* we have a problem */
    rb_raise(rb_eRuntimeError, "Could not create a validation context");
  }

#ifdef HAVE_XMLSCHEMASETVALIDSTRUCTUREDERRORS
  xmlSchemaSetValidStructuredErrors(
    valid_ctxt,
    Nokogiri_error_array_pusher,
    (void *)errors
  );
#endif

  xmlSchemaValidateDoc(valid_ctxt, doc);

  xmlSchemaFreeValidCtxt(valid_ctxt);

  return errors;
}