CloneDatabase.php

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<?php
use MediaWiki\MediaWikiServices;
use Wikimedia\Rdbms\IMaintainableDatabase;
 
class CloneDatabase {
    private $newTablePrefix = '';
 
    private $oldTablePrefix = '';
 
    private $tablesToClone = [];
 
    private $dropCurrentTables = true;
 
    private $useTemporaryTables = true;
 
    private $db;
 
    public function __construct( IMaintainableDatabase $db, array $tablesToClone,
        $newTablePrefix, $oldTablePrefix = '', $dropCurrentTables = true
    ) {
        $this->db = $db;
        $this->tablesToClone = $tablesToClone;
        $this->newTablePrefix = $newTablePrefix;
        $this->oldTablePrefix = $oldTablePrefix ? $oldTablePrefix : $this->db->tablePrefix();
        $this->dropCurrentTables = $dropCurrentTables;
    }
 
    public function useTemporaryTables( $u = true ) {
        $this->useTemporaryTables = $u;
    }
 
    public function cloneTableStructure() {
        global $wgSharedTables, $wgSharedDB;
        foreach ( $this->tablesToClone as $tbl ) {
            if ( $wgSharedDB && in_array( $tbl, $wgSharedTables, true ) ) {
                // Shared tables don't work properly when cloning due to
                // how prefixes are handled (T67654)
                throw new RuntimeException( "Cannot clone shared table $tbl." );
            }
            # Clean up from previous aborted run.  So that table escaping
            # works correctly across DB engines, we need to change the pre-
            # fix back and forth so tableName() works right.
 
            self::changePrefix( $this->oldTablePrefix );
            $oldTableName = $this->db->tableName( $tbl, 'raw' );
 
            self::changePrefix( $this->newTablePrefix );
            $newTableName = $this->db->tableName( $tbl, 'raw' );
 
            if ( $this->dropCurrentTables
                && !in_array( $this->db->getType(), [ 'postgres', 'oracle' ] )
            ) {
                if ( $oldTableName === $newTableName ) {
                    // Last ditch check to avoid data loss
                    throw new LogicException( "Not dropping new table, as '$newTableName'"
                        . " is name of both the old and the new table." );
                }
                $this->db->dropTable( $tbl, __METHOD__ );
                wfDebug( __METHOD__ . " dropping {$newTableName}\n" );
                // Dropping the oldTable because the prefix was changed
            }
 
            # Create new table
            wfDebug( __METHOD__ . " duplicating $oldTableName to $newTableName\n" );
            $this->db->duplicateTableStructure(
                $oldTableName, $newTableName, $this->useTemporaryTables );
        }
    }
 
    public function destroy( $dropTables = false ) {
        if ( $dropTables ) {
            self::changePrefix( $this->newTablePrefix );
            foreach ( $this->tablesToClone as $tbl ) {
                $this->db->dropTable( $tbl );
            }
        }
        self::changePrefix( $this->oldTablePrefix );
    }
 
    public static function changePrefix( $prefix ) {
        global $wgDBprefix;
 
        $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
        $lbFactory->setDomainPrefix( $prefix );
        $wgDBprefix = $prefix;
    }
}