includes/db/CloneDatabase.php

   1 <?php
   2 /**
   3  * Helper class for making a copy of the database, mostly for unit testing.
   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 use MediaWiki\MediaWikiServices;
  24 use Wikimedia\Rdbms\IMaintainableDatabase;
  25
  26 class CloneDatabase {
  27         /** Table prefix for cloning */
  28         private string $newTablePrefix;
  29
  30         /** Current table prefix */
  31         private string $oldTablePrefix;
  32
  33         /** List of tables to be cloned */
  34         private array $tablesToClone;
  35
  36         /** Should we DROP tables containing the new names? */
  37         private bool $dropCurrentTables;
  38
  39         /** Whether to use temporary tables or not */
  40         private bool $useTemporaryTables = true;
  41
  42         private IMaintainableDatabase $db;
  43
  44         /**
  45          * @param IMaintainableDatabase $db A database subclass
  46          * @param array $tablesToClone An array of tables to clone, unprefixed
  47          * @param string $newTablePrefix Prefix to assign to the tables
  48          * @param string|null $oldTablePrefix Prefix on current tables, if not $wgDBprefix
  49          * @param bool $dropCurrentTables
  50          */
  51         public function __construct(
  52                 IMaintainableDatabase $db,
  53                 array $tablesToClone,
  54                 string $newTablePrefix,
  55                 ?string $oldTablePrefix = null,
  56                 bool $dropCurrentTables = true
  57         ) {
  58                 if ( !$tablesToClone ) {
  59                         throw new InvalidArgumentException( 'Empty list of tables to clone' );
  60                 }
  61                 $this->db = $db;
  62                 $this->tablesToClone = $tablesToClone;
  63                 $this->newTablePrefix = $newTablePrefix;
  64                 $this->oldTablePrefix = $oldTablePrefix ?? $this->db->tablePrefix();
  65                 $this->dropCurrentTables = $dropCurrentTables;
  66         }
  67
  68         /**
  69          * Set whether to use temporary tables or not
  70          * @param bool $u Use temporary tables when cloning the structure
  71          */
  72         public function useTemporaryTables( bool $u = true ): void {
  73                 $this->useTemporaryTables = $u;
  74         }
  75
  76         public function cloneTableStructure(): void {
  77                 global $wgSharedTables, $wgSharedDB;
  78                 foreach ( $this->tablesToClone as $tbl ) {
  79                         if ( $wgSharedDB && in_array( $tbl, $wgSharedTables, true ) ) {
  80                                 // Shared tables don't work properly when cloning due to
  81                                 // how prefixes are handled (T67654)
  82                                 throw new RuntimeException( "Cannot clone shared table $tbl." );
  83                         }
  84                         # Clean up from previous aborted run.  So that table escaping
  85                         # works correctly across DB engines, we need to change the pre-
  86                         # fix back and forth so tableName() works right.
  87
  88                         $this->db->tablePrefix( $this->oldTablePrefix );
  89                         $oldTableName = $this->db->tableName( $tbl, 'raw' );
  90
  91                         $this->db->tablePrefix( $this->newTablePrefix );
  92                         $newTableName = $this->db->tableName( $tbl, 'raw' );
  93
  94                         // Postgres: Temp tables are automatically deleted upon end of session
  95                         //           Same Temp table name hides existing table for current session
  96                         if ( $this->dropCurrentTables ) {
  97                                 if ( $oldTableName === $newTableName ) {
  98                                         // Last ditch check to avoid data loss
  99                                         throw new LogicException( "Not dropping new table, as '$newTableName'"
 100                                                 . " is name of both the old and the new table." );
 101                                 }
 102                                 $this->db->dropTable( $tbl, __METHOD__ );
 103                                 // Dropping the oldTable because the prefix was changed
 104                         }
 105
 106                         # Create new table
 107                         $this->db->duplicateTableStructure(
 108                                 $oldTableName, $newTableName, $this->useTemporaryTables, __METHOD__ );
 109                 }
 110         }
 111
 112         /**
 113          * Change the prefix back to the original.
 114          * @param bool $dropTables Optionally drop the tables we created
 115          */
 116         public function destroy( bool $dropTables = false ): void {
 117                 if ( $dropTables ) {
 118                         $this->db->tablePrefix( $this->newTablePrefix );
 119                         foreach ( $this->tablesToClone as $tbl ) {
 120                                 $this->db->dropTable( $tbl, __METHOD__ );
 121                         }
 122                 }
 123                 $this->db->tablePrefix( $this->oldTablePrefix );
 124         }
 125
 126         /**
 127          * Change the table prefix on all open DB connections
 128          *
 129          * @param string $prefix
 130          * @return void
 131          */
 132         public static function changePrefix( string $prefix ): void {
 133                 global $wgDBprefix, $wgDBname;
 134
 135                 $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
 136                 $lbFactory->setLocalDomainPrefix( $prefix );
 137
 138                 $aliases = [
 139                         $wgDBname => $lbFactory->getLocalDomainID()
 140                 ];
 141                 $lbFactory->setDomainAliases( $aliases );
 142                 foreach ( $lbFactory->getAllLBs() as $lb ) {
 143                         $lb->setDomainAliases( $aliases );
 144                 }
 145
 146                 $wgDBprefix = $prefix;
 147         }
 148 }