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  * @file
  24  * @ingroup Database
  25  */
  26
  27 class CloneDatabase {
  28
  29         /**
  30          * Table prefix for cloning
  31          * @var String
  32          */
  33         private $newTablePrefix = '';
  34
  35         /**
  36          * Current table prefix
  37          * @var String
  38          */
  39         private $oldTablePrefix = '';
  40
  41         /**
  42          * List of tables to be cloned
  43          * @var Array
  44          */
  45         private $tablesToClone = array();
  46
  47         /**
  48          * Should we DROP tables containing the new names?
  49          * @var Bool
  50          */
  51         private $dropCurrentTables = true;
  52
  53         /**
  54          * Whether to use temporary tables or not
  55          * @var Bool
  56          */
  57         private $useTemporaryTables = true;
  58
  59         /**
  60          * Constructor
  61          *
  62          * @param $db DatabaseBase A database subclass
  63          * @param array $tablesToClone An array of tables to clone, unprefixed
  64          * @param string $newTablePrefix Prefix to assign to the tables
  65          * @param string $oldTablePrefix Prefix on current tables, if not $wgDBprefix
  66          * @param $dropCurrentTables bool
  67          */
  68         public function __construct( DatabaseBase $db, array $tablesToClone,
  69                 $newTablePrefix, $oldTablePrefix = '', $dropCurrentTables = true )
  70         {
  71                 $this->db = $db;
  72                 $this->tablesToClone = $tablesToClone;
  73                 $this->newTablePrefix = $newTablePrefix;
  74                 $this->oldTablePrefix = $oldTablePrefix ? $oldTablePrefix : $this->db->tablePrefix();
  75                 $this->dropCurrentTables = $dropCurrentTables;
  76         }
  77
  78         /**
  79          * Set whether to use temporary tables or not
  80          * @param bool $u Use temporary tables when cloning the structure
  81          */
  82         public function useTemporaryTables( $u = true ) {
  83                 $this->useTemporaryTables = $u;
  84         }
  85
  86         /**
  87          * Clone the table structure
  88          */
  89         public function cloneTableStructure() {
  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          * Change the prefix back to the original.
 115          * @param bool $dropTables Optionally drop the tables we created
 116          */
 117         public function destroy( $dropTables = false ) {
 118                 if( $dropTables ) {
 119                         self::changePrefix( $this->newTablePrefix );
 120                         foreach( $this->tablesToClone as $tbl ) {
 121                                 $this->db->dropTable( $tbl );
 122                         }
 123                 }
 124                 self::changePrefix( $this->oldTablePrefix );
 125         }
 126
 127         /**
 128          * Change the table prefix on all open DB connections/
 129          *
 130          * @param  $prefix
 131          * @return void
 132          */
 133         public static function changePrefix( $prefix ) {
 134                 global $wgDBprefix;
 135                 wfGetLBFactory()->forEachLB( array( 'CloneDatabase', 'changeLBPrefix' ), array( $prefix ) );
 136                 $wgDBprefix = $prefix;
 137         }
 138
 139         /**
 140          * @param  $lb LoadBalancer
 141          * @param  $prefix
 142          * @return void
 143          */
 144         public static function changeLBPrefix( $lb, $prefix ) {
 145                 $lb->forEachOpenConnection( array( 'CloneDatabase', 'changeDBPrefix' ), array( $prefix ) );
 146         }
 147
 148         /**
 149          * @param  $db DatabaseBase
 150          * @param  $prefix
 151          * @return void
 152          */
 153         public static function changeDBPrefix( $db, $prefix ) {
 154                 $db->tablePrefix( $prefix );
 155         }
 156 }