includes/dao/DBAccessObjectUtils.php

   1 <?php
   2 /**
   3  * This file contains database access object related constants.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Database
  22  */
  23
  24 /**
  25  * Helper class for DAO classes
  26  *
  27  * @since 1.26
  28  */
  29 class DBAccessObjectUtils {
  30         /**
  31          * @param integer $bitfield
  32          * @param integer $flags IDBAccessObject::READ_* constant
  33          * @return bool Bitfield has flag $flag set
  34          */
  35         public static function hasFlags( $bitfield, $flags ) {
  36                 return ( $bitfield & $flags ) == $flags;
  37         }
  38
  39         /**
  40          * Get an appropriate DB index and options for a query
  41          *
  42          * @param integer $bitfield
  43          * @return array (DB_MASTER/DB_SLAVE, SELECT options array)
  44          */
  45         public static function getDBOptions( $bitfield ) {
  46                 $index = self::hasFlags( $bitfield, IDBAccessObject::READ_LATEST )
  47                         ? DB_MASTER
  48                         : DB_SLAVE;
  49
  50                 $options = array();
  51                 if ( self::hasFlags( $bitfield, IDBAccessObject::READ_EXCLUSIVE ) ) {
  52                         $options[] = 'FOR UPDATE';
  53                 } elseif ( self::hasFlags( $bitfield, IDBAccessObject::READ_LOCKING ) ) {
  54                         $options[] = 'LOCK IN SHARE MODE';
  55                 }
  56
  57                 return array( $index, $options );
  58         }
  59 }