CloneDatabase.php

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<?php
namespace MediaWiki\DB;
 
use InvalidArgumentException;
use LogicException;
use MediaWiki\MediaWikiServices;
use RuntimeException;
use Wikimedia\Rdbms\IMaintainableDatabase;
 
class CloneDatabase {
    private string $newTablePrefix;
 
    private string $oldTablePrefix;
 
    private array $tablesToClone;
 
    private bool $dropCurrentTables;
 
    private bool $useTemporaryTables = true;
 
    private IMaintainableDatabase $db;
 
    public function __construct(
        IMaintainableDatabase $db,
        array $tablesToClone,
        string $newTablePrefix,
        ?string $oldTablePrefix = null,
        bool $dropCurrentTables = true
    ) {
        if ( !$tablesToClone ) {
            throw new InvalidArgumentException( 'Empty list of tables to clone' );
        }
        $this->db = $db;
        $this->tablesToClone = $tablesToClone;
        $this->newTablePrefix = $newTablePrefix;
        $this->oldTablePrefix = $oldTablePrefix ?? $this->db->tablePrefix();
        $this->dropCurrentTables = $dropCurrentTables;
    }
 
    public function useTemporaryTables( bool $u = true ): void {
        $this->useTemporaryTables = $u;
    }
 
    public function cloneTableStructure(): void {
        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.
 
            $this->db->tablePrefix( $this->oldTablePrefix );
            $oldTableName = $this->db->tableName( $tbl, 'raw' );
 
            $this->db->tablePrefix( $this->newTablePrefix );
            $newTableName = $this->db->tableName( $tbl, 'raw' );
 
            // Postgres: Temp tables are automatically deleted upon end of session
            //           Same Temp table name hides existing table for current session
            if ( $this->dropCurrentTables ) {
                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__ );
                // Dropping the oldTable because the prefix was changed
            }
 
            # Create new table
            $this->db->duplicateTableStructure(
                $oldTableName, $newTableName, $this->useTemporaryTables, __METHOD__ );
        }
    }
 
    public function destroy( bool $dropTables = false ): void {
        if ( $dropTables ) {
            $this->db->tablePrefix( $this->newTablePrefix );
            foreach ( $this->tablesToClone as $tbl ) {
                $this->db->dropTable( $tbl, __METHOD__ );
            }
        }
        $this->db->tablePrefix( $this->oldTablePrefix );
    }
 
    public static function changePrefix( string $prefix ): void {
        global $wgDBprefix, $wgDBname;
 
        $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
        $lbFactory->setLocalDomainPrefix( $prefix );
 
        $aliases = [
            $wgDBname => $lbFactory->getLocalDomainID()
        ];
        $lbFactory->setDomainAliases( $aliases );
        foreach ( $lbFactory->getAllLBs() as $lb ) {
            $lb->setDomainAliases( $aliases );
        }
 
        $wgDBprefix = $prefix;
    }
}
 
class_alias( CloneDatabase::class, 'CloneDatabase' );