~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Copyright (C) 2008 Sun Microsystems, Inc.

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; version 2 of the License.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

#include "config.h"

#include <cstdio>

#include "drizzled/tzfile.h"

#include "drizzled/tztime.h"

#include "drizzled/gettext.h"

#include "drizzled/session.h"

#include "drizzled/time_functions.h"

namespace drizzled

{

/**

 * String with names of SYSTEM time zone.

 */

static const String tz_SYSTEM_name("SYSTEM", 6, &my_charset_utf8_general_ci);

/**

 * Instance of this class represents local time zone used on this system

 * (specified by TZ environment variable or via any other system mechanism).

 * It uses system functions (localtime_r, my_system_gmt_sec) for conversion

 * and is always available. Because of this it is used by default - if there

 * were no explicit time zone specified. On the other hand because of this

 * conversion methods provided by this class is significantly slower and

 * possibly less multi-threaded-friendly than corresponding Time_zone_db

 * methods so the latter should be preffered there it is possible.

 */

class Time_zone_system : public Time_zone

{

public:

  Time_zone_system() {}                       /* Remove gcc warning */

  virtual type::Time::epoch_t TIME_to_gmt_sec(const type::Time &t,

                                              bool *in_dst_time_gap) const;

  virtual void gmt_sec_to_TIME(type::Time &tmp, type::Time::epoch_t t) const;

  virtual const String * get_name() const;

};

/**

 * @brief

 * Converts local time in system time zone in type::Time representation

 * to its type::Time::epoch_t representation.

 *

 * @details

 * This method uses system function (localtime_r()) for conversion

 * local time in system time zone in type::Time structure to its type::Time::epoch_t

 * representation. Unlike the same function for Time_zone_db class

 * it it won't handle unnormalized input properly. Still it will

 * return lowest possible type::Time::epoch_t in case of ambiguity or if we

 * provide time corresponding to the time-gap.

 *

 * You should call init_time() function before using this function.

 *

 * @param   t               pointer to type::Time structure with local time in

 *                          broken-down representation.

 * @param   in_dst_time_gap pointer to bool which is set to true if datetime

 *                          value passed doesn't really exist (i.e. falls into

 *                          spring time-gap) and is not touched otherwise.

 *

 * @return

 * Corresponding type::Time::epoch_t value or 0 in case of error

 */

type::Time::epoch_t

Time_zone_system::TIME_to_gmt_sec(const type::Time &t, bool *in_dst_time_gap) const

{

  long not_used;

  type::Time::epoch_t tmp;

  t.convert(tmp, &not_used, in_dst_time_gap);

  return tmp;

}

/**

 * @brief

 * Converts time from UTC seconds since Epoch (type::Time::epoch_t) representation

 * to system local time zone broken-down representation.

 *

 * @param    tmp   pointer to type::Time structure to fill-in

 * @param    t     type::Time::epoch_t value to be converted

 *

 * Note: We assume that value passed to this function will fit into type::Time::epoch_t range

 * supported by localtime_r. This conversion is putting restriction on

 * TIMESTAMP range in MySQL. If we can get rid of SYSTEM time zone at least

 * for interaction with client then we can extend TIMESTAMP range down to

 * the 1902 easily.

 */

void

Time_zone_system::gmt_sec_to_TIME(type::Time &tmp, type::Time::epoch_t t) const

{

  tmp.store(t);

}

/**

 * @brief

 * Get name of time zone

 *

 * @return

 * Name of time zone as String

 */

const String *

Time_zone_system::get_name() const

{

  return &tz_SYSTEM_name;

}

static Time_zone_system tz_SYSTEM;

Time_zone *my_tz_SYSTEM= &tz_SYSTEM;

/**

 * @brief

 * Initialize time zone support infrastructure.

 *

 * @details

 * This function will init memory structures needed for time zone support,

 * it will register mandatory SYSTEM time zone in them. It will try to open

 * mysql.time_zone* tables and load information about default time zone and

 * information which further will be shared among all time zones loaded.

 * If system tables with time zone descriptions don't exist it won't fail

 * (unless default_tzname is time zone from tables). If bootstrap parameter

 * is true then this routine assumes that we are in bootstrap mode and won't

 * load time zone descriptions unless someone specifies default time zone

 * which is supposedly stored in those tables.

 * It'll also set default time zone if it is specified.

 *

 * @param   session            current thread object

 * @param   default_tzname     default time zone or 0 if none.

 * @param   bootstrap          indicates whenever we are in bootstrap mode

 *

 * @return

 *  0 - ok

 *  1 - Error

 */

bool

my_tz_init(Session *session, const char *default_tzname)

{

  if (default_tzname)

  {

    String tmp_tzname2(default_tzname, &my_charset_utf8_general_ci);

    /*

      Time zone tables may be open here, and my_tz_find() may open

      most of them once more, but this is OK for system tables open

      for READ.

    */

    if (!(global_system_variables.time_zone= my_tz_find(session, &tmp_tzname2)))

    {

      errmsg_printf(error::ERROR,

                    _("Fatal error: Illegal or unknown default time zone '%s'"),

                    default_tzname);

      return true;

    }

  }

  return false;

}

/**

 * @brief

 * Get Time_zone object for specified time zone.

 *

 * @todo

 * Not implemented yet. This needs to hook into some sort of OS system call.

 */

Time_zone *

my_tz_find(Session *,

           const String *)

{

  return NULL;

}

} /* namespace drizzled */