includes/libs/rdbms/loadbalancer/LoadBalancerSingle.php

   1 <?php
   2 /**
   3  * Simple generator of database connections that always returns the same object.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Database
  22  */
  23
  24 namespace Wikimedia\Rdbms;
  25
  26 use InvalidArgumentException;
  27
  28 /**
  29  * Trivial LoadBalancer that always returns an injected connection handle
  30  */
  31 class LoadBalancerSingle extends LoadBalancer {
  32         /** @var IDatabase */
  33         private $db;
  34
  35         /**
  36          * @param array $params An associative array with one member:
  37          *   - connection: An IDatabase connection object
  38          */
  39         public function __construct( array $params ) {
  40                 if ( !isset( $params['connection'] ) ) {
  41                         throw new InvalidArgumentException( "Missing 'connection' argument." );
  42                 }
  43
  44                 $this->db = $params['connection'];
  45
  46                 parent::__construct( [
  47                         'servers' => [
  48                                 [
  49                                         'type' => $this->db->getType(),
  50                                         'host' => $this->db->getServer(),
  51                                         'dbname' => $this->db->getDBname(),
  52                                         'load' => 1,
  53                                 ]
  54                         ],
  55                         'trxProfiler' => isset( $params['trxProfiler'] ) ? $params['trxProfiler'] : null,
  56                         'srvCache' => isset( $params['srvCache'] ) ? $params['srvCache'] : null,
  57                         'wanCache' => isset( $params['wanCache'] ) ? $params['wanCache'] : null
  58                 ] );
  59
  60                 if ( isset( $params['readOnlyReason'] ) ) {
  61                         $this->db->setLBInfo( 'readOnlyReason', $params['readOnlyReason'] );
  62                 }
  63         }
  64
  65         /**
  66          * @param IDatabase $db Live connection handle
  67          * @param array $params Parameter map to LoadBalancerSingle::__constructs()
  68          * @return LoadBalancerSingle
  69          * @since 1.28
  70          */
  71         public static function newFromConnection( IDatabase $db, array $params = [] ) {
  72                 return new static( [ 'connection' => $db ] + $params );
  73         }
  74
  75         protected function reallyOpenConnection( array $server, $dbNameOverride ) {
  76                 return $this->db;
  77         }
  78 }
  79
  80 class_alias( LoadBalancerSingle::class, 'LoadBalancerSingle' );