includes/db/CloneDatabase.php

   1 <?php
   2 /**
   3  * Helper class for making a copy of the database, mostly for unit testing.
   4  *
   5  * Copyright © 2010 Chad Horohoe <chad@anyonecanedit.org>
   6  * http://www.mediawiki.org/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @ingroup Database
  24  */
  25
  26 class CloneDatabase {
  27
  28         /**
  29          * Table prefix for cloning
  30          * @var String
  31          */
  32         private $newTablePrefix = '';
  33
  34         /**
  35          * Current table prefix
  36          * @var String
  37          */
  38         private $oldTablePrefix = '';
  39
  40         /**
  41          * List of tables to be cloned
  42          * @var Array
  43          */
  44         private $tablesToClone = array();
  45
  46         /**
  47          * Should we DROP tables containing the new names?
  48          * @var Bool
  49          */
  50         private $dropCurrentTables = true;
  51
  52         /**
  53          * Whether to use temporary tables or not
  54          * @var Bool
  55          */
  56         private $useTemporaryTables = true;
  57
  58         /**
  59          * Constructor
  60          *
  61          * @param $db DatabaseBase A database subclass
  62          * @param $tablesToClone Array An array of tables to clone, unprefixed
  63          * @param $newTablePrefix String Prefix to assign to the tables
  64          * @param $oldTablePrefix String Prefix on current tables, if not $wgDBprefix
  65          * @param $dropCurrentTables bool
  66          */
  67         public function __construct( DatabaseBase $db, array $tablesToClone,
  68                 $newTablePrefix, $oldTablePrefix = '', $dropCurrentTables = true )
  69         {
  70                 $this->db = $db;
  71                 $this->tablesToClone = $tablesToClone;
  72                 $this->newTablePrefix = $newTablePrefix;
  73                 $this->oldTablePrefix = $oldTablePrefix ? $oldTablePrefix : $this->db->tablePrefix();
  74                 $this->dropCurrentTables = $dropCurrentTables;
  75         }
  76
  77         /**
  78          * Set whether to use temporary tables or not
  79          * @param $u Bool Use temporary tables when cloning the structure
  80          */
  81         public function useTemporaryTables( $u = true ) {
  82                 $this->useTemporaryTables = $u;
  83         }
  84
  85         /**
  86          * Clone the table structure
  87          */
  88         public function cloneTableStructure() {
  89
  90                 foreach( $this->tablesToClone as $tbl ) {
  91                         # Clean up from previous aborted run.  So that table escaping
  92                         # works correctly across DB engines, we need to change the pre-
  93                         # fix back and forth so tableName() works right.
  94
  95                         self::changePrefix( $this->oldTablePrefix );
  96                         $oldTableName = $this->db->tableName( $tbl, 'raw' );
  97
  98                         self::changePrefix( $this->newTablePrefix );
  99                         $newTableName = $this->db->tableName( $tbl, 'raw' );
 100
 101                         if( $this->dropCurrentTables && !in_array( $this->db->getType(), array( 'postgres', 'oracle' ) ) ) {
 102                                 $this->db->dropTable( $tbl, __METHOD__ );
 103                                 wfDebug( __METHOD__." dropping {$newTableName}\n", true);
 104                                 //Dropping the oldTable because the prefix was changed
 105                         }
 106
 107                         # Create new table
 108                         wfDebug( __METHOD__." duplicating $oldTableName to $newTableName\n", true );
 109                         $this->db->duplicateTableStructure( $oldTableName, $newTableName, $this->useTemporaryTables );
 110
 111                 }
 112
 113         }
 114
 115         /**
 116          * Change the prefix back to the original.
 117          * @param $dropTables bool Optionally drop the tables we created
 118          */
 119         public function destroy( $dropTables = false ) {
 120                 if( $dropTables ) {
 121                         self::changePrefix( $this->newTablePrefix );
 122                         foreach( $this->tablesToClone as $tbl ) {
 123                                 $this->db->dropTable( $tbl );
 124                         }
 125                 }
 126                 self::changePrefix( $this->oldTablePrefix );
 127         }
 128
 129         /**
 130          * Change the table prefix on all open DB connections/
 131          *
 132          * @param  $prefix
 133          * @return void
 134          */
 135         public static function changePrefix( $prefix ) {
 136                 global $wgDBprefix;
 137                 wfGetLBFactory()->forEachLB( array( 'CloneDatabase', 'changeLBPrefix' ), array( $prefix ) );
 138                 $wgDBprefix = $prefix;
 139         }
 140
 141         /**
 142          * @param  $lb LoadBalancer
 143          * @param  $prefix
 144          * @return void
 145          */
 146         public static function changeLBPrefix( $lb, $prefix ) {
 147                 $lb->forEachOpenConnection( array( 'CloneDatabase', 'changeDBPrefix' ), array( $prefix ) );
 148         }
 149
 150         /**
 151          * @param  $db DatabaseBase
 152          * @param  $prefix
 153          * @return void
 154          */
 155         public static function changeDBPrefix( $db, $prefix ) {
 156                 $db->tablePrefix( $prefix );
 157         }
 158 }