sqlpp11/include/sqlpp11/result_field.h

/*
 * Copyright (c) 2013-2015, Roland Bock
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 *   Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 *
 *   Redistributions in binary form must reproduce the above copyright notice, this
 *   list of conditions and the following disclaimer in the documentation and/or
 *   other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef SQLPP_RESULT_FIELD_H
#define SQLPP_RESULT_FIELD_H

#include <sqlpp11/wrong.h>
#include <sqlpp11/wrap_operand.h>
#include <sqlpp11/type_traits.h>

namespace sqlpp
{
  template <typename Db, typename FieldSpec>
  struct result_field_t
  {
    using X = typename FieldSpec::incorrect;
    static_assert(wrong_t<result_field_t>::value, "Missing specialization for result_field_t");
  };

  template <typename Context, typename Db, typename FieldSpec>
  struct serializer_t<Context, result_field_t<Db, FieldSpec>>
  {
    using _serialize_check = consistent_t;
    using T = result_field_t<Db, FieldSpec>;

    static Context& _(const T& t, Context& context)
    {
      if (t.is_null() and not null_is_trivial_value_t<T>::value)
      {
        context << "NULL";
      }
      else
      {
        serialize(wrap_operand_t<cpp_value_type_of<FieldSpec>>(t.value()), context);
      }
      return context;
    }
  };

  template <typename Db, typename FieldSpec>
  inline std::ostream& operator<<(std::ostream& os, const result_field_t<Db, FieldSpec>& rf)
  {
    return serialize(rf, os);
  }
}
#endif