sqlpp11/include/sqlpp11/mysql/char_result.h

#pragma once

/*
 * 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.
 */

#include <ciso646>
#include <cstdlib>
#include <iostream>
#include <memory>
#include <sqlpp11/chrono.h>
#include <sqlpp11/detail/parse_date_time.h>
#include <sqlpp11/exception.h>
#include <sqlpp11/mysql/detail/result_handle.h>
#include <sqlpp11/mysql/sqlpp_mysql.h>
#include <sqlpp11/mysql/char_result_row.h>
#include <sqlpp11/compat/optional.h>
#include <sqlpp11/compat/string_view.h>
#include <sqlpp11/compat/span.h>

namespace sqlpp
{
  namespace mysql
  {
    class char_result_t
    {
      std::unique_ptr<detail::result_handle> _handle;
      char_result_row_t _char_result_row;

    public:
      char_result_t() = default;
      char_result_t(std::unique_ptr<detail::result_handle>&& handle) : _handle{std::move(handle)}
      {
        if (_invalid())
          throw sqlpp::exception{"MySQL: Constructing char_result without valid handle"};

        if (_handle->debug)
          std::cerr << "MySQL debug: Constructing result, using handle at " << _handle.get() << std::endl;
      }

      char_result_t(const char_result_t&) = delete;
      char_result_t(char_result_t&& rhs) = default;
      char_result_t& operator=(const char_result_t&) = delete;
      char_result_t& operator=(char_result_t&&) = default;
      ~char_result_t() = default;

      bool operator==(const char_result_t& rhs) const
      {
        return _handle == rhs._handle;
      }

      size_t size() const
      {
        return _handle ? mysql_num_rows(_handle->mysql_res) : size_t{};
      }

      template <typename ResultRow>
      void next(ResultRow& result_row)
      {
        if (_invalid())
        {
          result_row._invalidate();
          return;
        }

        if (next_impl())
        {
          if (not result_row)
          {
            result_row._validate();
          }
          result_row._read_fields(*this);
        }
        else
        {
          if (result_row)
            result_row._invalidate();
        }
      }

      bool _invalid() const
      {
        return !_handle or !*_handle;
      }

      void read_field(size_t index, bool& value)
      {
        value = (_char_result_row.data[index][0] == 't' or _char_result_row.data[index][0] == '1');
      }

      void read_field(size_t index, double& value)
      {
        value = std::strtod(_char_result_row.data[index], nullptr);
      }

      void read_field(size_t index, int64_t& value)
      {
        value = std::strtoll(_char_result_row.data[index], nullptr, 10);
      }

      void read_field(size_t index, uint64_t& value)
      {
        value = std::strtoull(_char_result_row.data[index], nullptr, 10);
      }

      void read_field(size_t index, sqlpp::compat::span<uint8_t>& value)
      {
        value = sqlpp::compat::span<uint8_t>(reinterpret_cast<const uint8_t*>(_char_result_row.data[index]), _char_result_row.len[index]);
      }

      void read_field(size_t index, sqlpp::compat::string_view& value)
      {
        value = sqlpp::compat::string_view(_char_result_row.data[index], _char_result_row.len[index]);
      }

      void read_field(size_t index, ::sqlpp::chrono::day_point& value)
      {
        if (_handle->debug)
          std::cerr << "MySQL debug: parsing date result at index: " << index << std::endl;

        const auto date_string = _char_result_row.data[index];
        if (_handle->debug)
          std::cerr << "MySQL debug: date string: " << date_string << std::endl;

        if (::sqlpp::detail::parse_date(value, date_string) == false)
        {
          if (_handle->debug)
            std::cerr << "MySQL debug: invalid date result: " << date_string << std::endl;
        }
      }

      void read_field(size_t index, ::sqlpp::chrono::microsecond_point& value)
      {
        if (_handle->debug)
          std::cerr << "MySQL debug: parsing date result at index: " << index << std::endl;

        const auto date_time_string = _char_result_row.data[index];
        if (_handle->debug)
          std::cerr << "MySQL debug: date_time string: " << date_time_string << std::endl;

        if (::sqlpp::detail::parse_timestamp(value, date_time_string) == false)
        {
          if (_handle->debug)
            std::cerr << "MySQL debug: invalid date_time result: " << date_time_string << std::endl;
        }
      }

      void read_field(size_t index, ::std::chrono::microseconds& value)
      {
        if (_handle->debug)
          std::cerr << "MySQL debug: parsing time of day result at index: " << index << std::endl;

        const auto time_string = _char_result_row.data[index];
        if (_handle->debug)
          std::cerr << "MySQL debug: time of day string: " << time_string << std::endl;

        if (::sqlpp::detail::parse_time_of_day(value, time_string) == false)
        {
          if (_handle->debug)
            std::cerr << "MySQL debug: invalid time result: " << time_string << std::endl;
        }
      }

      template <typename T>
      auto read_field(size_t index, sqlpp::compat::optional<T>& value) -> void
      {
        const bool is_null = _char_result_row.data[index] == nullptr;
        if (is_null)
        {
          value.reset();
        }
        else
        {
          if (not value)
          {
            value = T{};
          }
          read_field(index, *value);
        }
      }

    private:
      bool next_impl()
      {
        if (_handle->debug)
          std::cerr << "MySQL debug: Accessing next row of handle at " << _handle.get() << std::endl;

        _char_result_row.data = const_cast<const char**>(mysql_fetch_row(_handle->mysql_res));
        _char_result_row.len = mysql_fetch_lengths(_handle->mysql_res);

        return _char_result_row.data;
      }
    };
  }  // namespace mysql
}  // namespace sqlpp