DatabaseFlags.php

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<?php
namespace Wikimedia\Rdbms\Database;
 
use Wikimedia\Rdbms\DBLanguageError;
use Wikimedia\Rdbms\Platform\ISQLPlatform;
 
class DatabaseFlags implements IDatabaseFlags {
    protected $flags;
    private $priorFlags = [];
 
    protected const MUTABLE_FLAGS = [
        'DBO_DEBUG',
        'DBO_NOBUFFER',
        'DBO_TRX',
        'DBO_DDLMODE',
    ];
    protected const DBO_MUTABLE = (
        self::DBO_DEBUG | self::DBO_NOBUFFER | self::DBO_TRX | self::DBO_DDLMODE
    );
 
    public function __construct( $flags ) {
        $this->flags = $flags;
    }
 
    public function setFlag( $flag, $remember = self::REMEMBER_NOTHING ) {
        if ( $flag & ~static::DBO_MUTABLE ) {
            throw new DBLanguageError(
                "Got $flag (allowed: " . implode( ', ', static::MUTABLE_FLAGS ) . ')'
            );
        }
 
        if ( $remember === self::REMEMBER_PRIOR ) {
            $this->priorFlags[] = $this->flags;
        }
 
        $this->flags |= $flag;
    }
 
    public function clearFlag( $flag, $remember = self::REMEMBER_NOTHING ) {
        if ( $flag & ~static::DBO_MUTABLE ) {
            throw new DBLanguageError(
                "Got $flag (allowed: " . implode( ', ', static::MUTABLE_FLAGS ) . ')'
            );
        }
 
        if ( $remember === self::REMEMBER_PRIOR ) {
            $this->priorFlags[] = $this->flags;
        }
 
        $this->flags &= ~$flag;
    }
 
    public function restoreFlags( $state = self::RESTORE_PRIOR ) {
        if ( !$this->priorFlags ) {
            return;
        }
 
        if ( $state === self::RESTORE_INITIAL ) {
            $this->flags = reset( $this->priorFlags );
            $this->priorFlags = [];
        } else {
            $this->flags = array_pop( $this->priorFlags );
        }
    }
 
    public function getFlag( $flag ) {
        return ( ( $this->flags & $flag ) === $flag );
    }
 
    public static function contains( int $flags, int $bit ) {
        return ( ( $flags & $bit ) === $bit );
    }
 
    public function hasApplicableImplicitTrxFlag( int $queryFlags ) {
        return $this->hasImplicitTrxFlag() && !(
            self::contains( $queryFlags, ISQLPlatform::QUERY_CHANGE_TRX ) ||
            self::contains( $queryFlags, ISQLPlatform::QUERY_CHANGE_SCHEMA ) ||
            self::contains( $queryFlags, ISQLPlatform::QUERY_CHANGE_LOCKS ) ||
            self::contains( $queryFlags, ISQLPlatform::QUERY_IGNORE_DBO_TRX )
        );
    }
 
    public function hasImplicitTrxFlag() {
        return $this->getFlag( self::DBO_TRX );
    }
}