~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

 *

 *  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 <drizzled/server_includes.h>

#include <drizzled/definitions.h>

#include <drizzled/base.h>

#include <drizzled/handler.h>

#include <drizzled/handlerton.h>

#include <drizzled/session.h>

#include <drizzled/error.h>

#include <drizzled/gettext.h>

#include CSTDINT_H

/*

  While we have legacy_db_type, we have this array to

  check for dups and to find handlerton from legacy_db_type.

  Remove when legacy_db_type is finally gone

*/

st_plugin_int *hton2plugin[MAX_HA];

static handlerton *installed_htons[128];

static const LEX_STRING sys_table_aliases[]=

{

  { C_STRING_WITH_LEN("INNOBASE") },  { C_STRING_WITH_LEN("INNODB") },

  { C_STRING_WITH_LEN("HEAP") },      { C_STRING_WITH_LEN("MEMORY") },

  {NULL, 0}

};

handlerton *ha_resolve_by_legacy_type(Session *session,

                                      enum legacy_db_type db_type)

{

  plugin_ref plugin;

  switch (db_type) {

  case DB_TYPE_DEFAULT:

    return ha_default_handlerton(session);

  default:

    if (db_type > DB_TYPE_UNKNOWN && db_type < DB_TYPE_DEFAULT &&

        (plugin= ha_lock_engine(session, installed_htons[db_type])))

      return plugin_data(plugin, handlerton*);

    /* fall through */

  case DB_TYPE_UNKNOWN:

    return NULL;

  }

}

static plugin_ref ha_default_plugin(Session *session)

{

  if (session->variables.table_plugin)

    return session->variables.table_plugin;

  return my_plugin_lock(session, &global_system_variables.table_plugin);

}

/**

  Return the default storage engine handlerton for thread

  @param ha_default_handlerton(session)

  @param session         current thread

  @return

    pointer to handlerton

*/

handlerton *ha_default_handlerton(Session *session)

{

  plugin_ref plugin= ha_default_plugin(session);

  assert(plugin);

  handlerton *hton= plugin_data(plugin, handlerton*);

  assert(hton);

  return hton;

}

/**

  Return the storage engine handlerton for the supplied name

  @param session         current thread

  @param name        name of storage engine

  @return

    pointer to storage engine plugin handle

*/

plugin_ref ha_resolve_by_name(Session *session, const LEX_STRING *name)

{

  const LEX_STRING *table_alias;

  plugin_ref plugin;

redo:

  /* my_strnncoll is a macro and gcc doesn't do early expansion of macro */

  if (session && !my_charset_utf8_general_ci.coll->strnncoll(&my_charset_utf8_general_ci,

                           (const unsigned char *)name->str, name->length,

                           (const unsigned char *)STRING_WITH_LEN("DEFAULT"), 0))

    return ha_default_plugin(session);

  if ((plugin= my_plugin_lock_by_name(session, name, DRIZZLE_STORAGE_ENGINE_PLUGIN)))

  {

    handlerton *hton= plugin_data(plugin, handlerton *);

    if (!(hton->flags & HTON_NOT_USER_SELECTABLE))

      return plugin;

    /*

      unlocking plugin immediately after locking is relatively low cost.

    */

    plugin_unlock(session, plugin);

  }

  /*

    We check for the historical aliases.

  */

  for (table_alias= sys_table_aliases; table_alias->str; table_alias+= 2)

  {

    if (!my_strnncoll(&my_charset_utf8_general_ci,

                      (const unsigned char *)name->str, name->length,

                      (const unsigned char *)table_alias->str,

                      table_alias->length))

    {

      name= table_alias + 1;

      goto redo;

    }

  }

  return NULL;

}

plugin_ref ha_lock_engine(Session *session, handlerton *hton)

{

  if (hton)

  {

    st_plugin_int **plugin= hton2plugin + hton->slot;

    return my_plugin_lock(session, &plugin);

  }

  return NULL;

}

/**

  Use other database handler if databasehandler is not compiled in.

*/

handlerton *ha_checktype(Session *session, enum legacy_db_type database_type,

                          bool no_substitute, bool report_error)

{

  handlerton *hton= ha_resolve_by_legacy_type(session, database_type);

  if (ha_storage_engine_is_enabled(hton))

    return hton;

  if (no_substitute)

  {

    if (report_error)

    {

      const char *engine_name= ha_resolve_storage_engine_name(hton);

      my_error(ER_FEATURE_DISABLED,MYF(0),engine_name,engine_name);

    }

    return NULL;

  }

  return ha_default_handlerton(session);

} /* ha_checktype */

handler *get_new_handler(TABLE_SHARE *share, MEM_ROOT *alloc,

                         handlerton *db_type)

{

  handler *file;

  if (db_type && db_type->state == SHOW_OPTION_YES && db_type->create)

  {

    if ((file= db_type->create(db_type, share, alloc)))

      file->init();

    return(file);

  }

  /*

    Try the default table type

    Here the call to current_session() is ok as we call this function a lot of

    times but we enter this branch very seldom.

  */

  return(get_new_handler(share, alloc, ha_default_handlerton(current_session)));

}

int ha_finalize_handlerton(st_plugin_int *plugin)

{

  handlerton *hton= (handlerton *)plugin->data;

  switch (hton->state)

  {

  case SHOW_OPTION_NO:

  case SHOW_OPTION_DISABLED:

    break;

  case SHOW_OPTION_YES:

    if (installed_htons[hton->db_type] == hton)

      installed_htons[hton->db_type]= NULL;

    break;

  };

  if (hton && plugin->plugin->deinit)

    (void)plugin->plugin->deinit(hton);

  free((unsigned char*)hton);

  return(0);

}

int ha_initialize_handlerton(st_plugin_int *plugin)

{

  handlerton *hton;

  hton= (handlerton *)my_malloc(sizeof(handlerton),

                                MYF(MY_WME | MY_ZEROFILL));

  /*

    FIXME: the MY_ZEROFILL flag above doesn't zero all the bytes.

    This was detected after adding get_backup_engine member to handlerton

    structure. Apparently get_backup_engine was not NULL even though it was

    not initialized.

   */

  memset(hton, 0, sizeof(hton));

  /* Historical Requirement */

  plugin->data= hton; // shortcut for the future

  if (plugin->plugin->init)

  {

    if (plugin->plugin->init(hton))

    {

      sql_print_error(_("Plugin '%s' init function returned error."),

                      plugin->name.str);

      goto err;

    }

  }

  hton->name= plugin->name.str;

  /*

    the switch below and hton->state should be removed when

    command-line options for plugins will be implemented

  */

  switch (hton->state) {

  case SHOW_OPTION_NO:

    break;

  case SHOW_OPTION_YES:

    {

      uint32_t tmp;

      /* now check the db_type for conflict */

      if (hton->db_type <= DB_TYPE_UNKNOWN ||

          hton->db_type >= DB_TYPE_DEFAULT ||

          installed_htons[hton->db_type])

      {

        int idx= (int) DB_TYPE_FIRST_DYNAMIC;

        while (idx < (int) DB_TYPE_DEFAULT && installed_htons[idx])

          idx++;

        if (idx == (int) DB_TYPE_DEFAULT)

        {

          sql_print_warning(_("Too many storage engines!"));

          return(1);

        }

        if (hton->db_type != DB_TYPE_UNKNOWN)

          sql_print_warning(_("Storage engine '%s' has conflicting typecode. "

                            "Assigning value %d."), plugin->plugin->name, idx);

        hton->db_type= (enum legacy_db_type) idx;

      }

      installed_htons[hton->db_type]= hton;

      tmp= hton->savepoint_offset;

      hton->savepoint_offset= savepoint_alloc_size;

      savepoint_alloc_size+= tmp;

      hton->slot= total_ha++;

      hton2plugin[hton->slot]=plugin;

      if (hton->prepare)

        total_ha_2pc++;

      break;

    }

    /* fall through */

  default:

    hton->state= SHOW_OPTION_DISABLED;

    break;

  }

  /*

    This is entirely for legacy. We will create a new "disk based" hton and a

    "memory" hton which will be configurable longterm. We should be able to

    remove partition and myisammrg.

  */

  if (strcmp(plugin->plugin->name, "MEMORY") == 0)

    heap_hton= hton;

  if (strcmp(plugin->plugin->name, "MyISAM") == 0)

    myisam_hton= hton;

  return(0);

err:

  return(1);

}

enum legacy_db_type ha_legacy_type(const handlerton *db_type)

{

  return (db_type == NULL) ? DB_TYPE_UNKNOWN : db_type->db_type;

}

const char *ha_resolve_storage_engine_name(const handlerton *db_type)

{

  return db_type == NULL ? "UNKNOWN" : hton2plugin[db_type->slot]->name.str;

}

bool ha_check_storage_engine_flag(const handlerton *db_type, uint32_t flag)

{

  return db_type == NULL ? false : test(db_type->flags & flag);

}

bool ha_storage_engine_is_enabled(const handlerton *db_type)

{

  return (db_type && db_type->create) ?

         (db_type->state == SHOW_OPTION_YES) : false;

}

LEX_STRING *ha_storage_engine_name(const handlerton *hton)

{

  return &hton2plugin[hton->slot]->name;

}