DBAccessObjectUtils.php

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<?php
use Wikimedia\Rdbms\IConnectionProvider;
use Wikimedia\Rdbms\IReadableDatabase;
 
class DBAccessObjectUtils implements IDBAccessObject {
    public static function hasFlags( $bitfield, $flags ) {
        return ( $bitfield & $flags ) == $flags;
    }
 
    public static function getDBOptions( $bitfield ) {
        if ( self::hasFlags( $bitfield, self::READ_LATEST_IMMUTABLE ) ) {
            $index = DB_REPLICA; // override READ_LATEST if set
            $fallbackIndex = DB_PRIMARY;
        } elseif ( self::hasFlags( $bitfield, self::READ_LATEST ) ) {
            $index = DB_PRIMARY;
            $fallbackIndex = null;
        } else {
            $index = DB_REPLICA;
            $fallbackIndex = null;
        }
 
        $lockingOptions = [];
        if ( self::hasFlags( $bitfield, self::READ_EXCLUSIVE ) ) {
            $lockingOptions[] = 'FOR UPDATE';
        } elseif ( self::hasFlags( $bitfield, self::READ_LOCKING ) ) {
            $lockingOptions[] = 'LOCK IN SHARE MODE';
        }
 
        if ( $fallbackIndex !== null ) {
            $options = []; // locks on DB_REPLICA make no sense
            $fallbackOptions = $lockingOptions;
        } else {
            $options = $lockingOptions;
            $fallbackOptions = []; // no fallback
        }
 
        return [ $index, $options, $fallbackIndex, $fallbackOptions ];
    }
 
    public static function getDBFromIndex( IConnectionProvider $dbProvider, int $index ): IReadableDatabase {
        if ( $index === DB_PRIMARY ) {
            return $dbProvider->getPrimaryDatabase();
        } elseif ( $index === DB_REPLICA ) {
            return $dbProvider->getReplicaDatabase();
        } else {
            throw new InvalidArgumentException( '$index must be either DB_REPLICA or DB_PRIMARY' );
        }
    }
}