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 $tablesToClone Array An array of tables to clone, unprefixed
  64          * @param $newTablePrefix String Prefix to assign to the tables
  65          * @param $oldTablePrefix String 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 $u Bool 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
  91                 foreach( $this->tablesToClone as $tbl ) {
  92                         # Clean up from previous aborted run.  So that table escaping
  93                         # works correctly across DB engines, we need to change the pre-
  94                         # fix back and forth so tableName() works right.
  95
  96                         self::changePrefix( $this->oldTablePrefix );
  97                         $oldTableName = $this->db->tableName( $tbl, 'raw' );
  98
  99                         self::changePrefix( $this->newTablePrefix );
 100                         $newTableName = $this->db->tableName( $tbl, 'raw' );
 101
 102                         if( $this->dropCurrentTables && !in_array( $this->db->getType(), array( 'postgres', 'oracle' ) ) ) {
 103                                 $this->db->dropTable( $tbl, __METHOD__ );
 104                                 wfDebug( __METHOD__." dropping {$newTableName}\n", true);
 105                                 //Dropping the oldTable because the prefix was changed
 106                         }
 107
 108                         # Create new table
 109                         wfDebug( __METHOD__." duplicating $oldTableName to $newTableName\n", true );
 110                         $this->db->duplicateTableStructure( $oldTableName, $newTableName, $this->useTemporaryTables );
 111
 112                 }
 113
 114         }
 115
 116         /**
 117          * Change the prefix back to the original.
 118          * @param $dropTables bool Optionally drop the tables we created
 119          */
 120         public function destroy( $dropTables = false ) {
 121                 if( $dropTables ) {
 122                         self::changePrefix( $this->newTablePrefix );
 123                         foreach( $this->tablesToClone as $tbl ) {
 124                                 $this->db->dropTable( $tbl );
 125                         }
 126                 }
 127                 self::changePrefix( $this->oldTablePrefix );
 128         }
 129
 130         /**
 131          * Change the table prefix on all open DB connections/
 132          *
 133          * @param  $prefix
 134          * @return void
 135          */
 136         public static function changePrefix( $prefix ) {
 137                 global $wgDBprefix;
 138                 wfGetLBFactory()->forEachLB( array( 'CloneDatabase', 'changeLBPrefix' ), array( $prefix ) );
 139                 $wgDBprefix = $prefix;
 140         }
 141
 142         /**
 143          * @param  $lb LoadBalancer
 144          * @param  $prefix
 145          * @return void
 146          */
 147         public static function changeLBPrefix( $lb, $prefix ) {
 148                 $lb->forEachOpenConnection( array( 'CloneDatabase', 'changeDBPrefix' ), array( $prefix ) );
 149         }
 150
 151         /**
 152          * @param  $db DatabaseBase
 153          * @param  $prefix
 154          * @return void
 155          */
 156         public static function changeDBPrefix( $db, $prefix ) {
 157                 $db->tablePrefix( $prefix );
 158         }
 159 }