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   1  <?php
   2  /**
   3   * Helper class for making a copy of the database, mostly for unit testing.
   4   *
   5   * Copyright © 2010 Chad Horohoe <[email protected]>
   6   * https://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      /** @var string Table prefix for cloning */
  29      private $newTablePrefix = '';
  30  
  31      /** @var string Current table prefix */
  32      private $oldTablePrefix = '';
  33  
  34      /** @var array List of tables to be cloned */
  35      private $tablesToClone = array();
  36  
  37      /** @var bool Should we DROP tables containing the new names? */
  38      private $dropCurrentTables = true;
  39  
  40      /** @var bool Whether to use temporary tables or not */
  41      private $useTemporaryTables = true;
  42  
  43      /**
  44       * Constructor
  45       *
  46       * @param DatabaseBase $db A database subclass
  47       * @param array $tablesToClone An array of tables to clone, unprefixed
  48       * @param string $newTablePrefix Prefix to assign to the tables
  49       * @param string $oldTablePrefix Prefix on current tables, if not $wgDBprefix
  50       * @param bool $dropCurrentTables
  51       */
  52  	public function __construct( DatabaseBase $db, array $tablesToClone,
  53          $newTablePrefix, $oldTablePrefix = '', $dropCurrentTables = true
  54      ) {
  55          $this->db = $db;
  56          $this->tablesToClone = $tablesToClone;
  57          $this->newTablePrefix = $newTablePrefix;
  58          $this->oldTablePrefix = $oldTablePrefix ? $oldTablePrefix : $this->db->tablePrefix();
  59          $this->dropCurrentTables = $dropCurrentTables;
  60      }
  61  
  62      /**
  63       * Set whether to use temporary tables or not
  64       * @param bool $u Use temporary tables when cloning the structure
  65       */
  66  	public function useTemporaryTables( $u = true ) {
  67          $this->useTemporaryTables = $u;
  68      }
  69  
  70      /**
  71       * Clone the table structure
  72       */
  73  	public function cloneTableStructure() {
  74          global $wgSharedTables, $wgSharedDB;
  75          foreach ( $this->tablesToClone as $tbl ) {
  76              if ( $wgSharedDB && in_array( $tbl, $wgSharedTables, true ) ) {
  77                  // Shared tables don't work properly when cloning due to
  78                  // how prefixes are handled (bug 65654)
  79                  throw new MWException( "Cannot clone shared table $tbl." );
  80              }
  81              # Clean up from previous aborted run.  So that table escaping
  82              # works correctly across DB engines, we need to change the pre-
  83              # fix back and forth so tableName() works right.
  84  
  85              self::changePrefix( $this->oldTablePrefix );
  86              $oldTableName = $this->db->tableName( $tbl, 'raw' );
  87  
  88              self::changePrefix( $this->newTablePrefix );
  89              $newTableName = $this->db->tableName( $tbl, 'raw' );
  90  
  91              if ( $this->dropCurrentTables
  92                  && !in_array( $this->db->getType(), array( 'postgres', 'oracle' ) )
  93              ) {
  94                  if ( $oldTableName === $newTableName ) {
  95                      // Last ditch check to avoid data loss
  96                      throw new MWException( "Not dropping new table, as '$newTableName'"
  97                          . " is name of both the old and the new table." );
  98                  }
  99                  $this->db->dropTable( $tbl, __METHOD__ );
 100                  wfDebug( __METHOD__ . " dropping {$newTableName}\n" );
 101                  //Dropping the oldTable because the prefix was changed
 102              }
 103  
 104              # Create new table
 105              wfDebug( __METHOD__ . " duplicating $oldTableName to $newTableName\n" );
 106              $this->db->duplicateTableStructure( $oldTableName, $newTableName, $this->useTemporaryTables );
 107          }
 108      }
 109  
 110      /**
 111       * Change the prefix back to the original.
 112       * @param bool $dropTables Optionally drop the tables we created
 113       */
 114  	public function destroy( $dropTables = false ) {
 115          if ( $dropTables ) {
 116              self::changePrefix( $this->newTablePrefix );
 117              foreach ( $this->tablesToClone as $tbl ) {
 118                  $this->db->dropTable( $tbl );
 119              }
 120          }
 121          self::changePrefix( $this->oldTablePrefix );
 122      }
 123  
 124      /**
 125       * Change the table prefix on all open DB connections/
 126       *
 127       * @param string $prefix
 128       * @return void
 129       */
 130  	public static function changePrefix( $prefix ) {
 131          global $wgDBprefix;
 132          wfGetLBFactory()->forEachLB( array( 'CloneDatabase', 'changeLBPrefix' ), array( $prefix ) );
 133          $wgDBprefix = $prefix;
 134      }
 135  
 136      /**
 137       * @param LoadBalancer $lb
 138       * @param string $prefix
 139       * @return void
 140       */
 141  	public static function changeLBPrefix( $lb, $prefix ) {
 142          $lb->forEachOpenConnection( array( 'CloneDatabase', 'changeDBPrefix' ), array( $prefix ) );
 143      }
 144  
 145      /**
 146       * @param DatabaseBase $db
 147       * @param string $prefix
 148       * @return void
 149       */
 150  	public static function changeDBPrefix( $db, $prefix ) {
 151          $db->tablePrefix( $prefix );
 152      }
 153  }