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 IDatabase;
  27 use InvalidArgumentException;
  28
  29 /**
  30  * Trivial LoadBalancer that always returns an injected connection handle
  31  */
  32 class LoadBalancerSingle extends LoadBalancer {
  33         /** @var IDatabase */
  34         private $db;
  35
  36         /**
  37          * @param array $params An associative array with one member:
  38          *   - connection: An IDatabase connection object
  39          */
  40         public function __construct( array $params ) {
  41                 if ( !isset( $params['connection'] ) ) {
  42                         throw new InvalidArgumentException( "Missing 'connection' argument." );
  43                 }
  44
  45                 $this->db = $params['connection'];
  46
  47                 parent::__construct( [
  48                         'servers' => [
  49                                 [
  50                                         'type' => $this->db->getType(),
  51                                         'host' => $this->db->getServer(),
  52                                         'dbname' => $this->db->getDBname(),
  53                                         'load' => 1,
  54                                 ]
  55                         ],
  56                         'trxProfiler' => isset( $params['trxProfiler'] ) ? $params['trxProfiler'] : null,
  57                         'srvCache' => isset( $params['srvCache'] ) ? $params['srvCache'] : null,
  58                         'wanCache' => isset( $params['wanCache'] ) ? $params['wanCache'] : null
  59                 ] );
  60
  61                 if ( isset( $params['readOnlyReason'] ) ) {
  62                         $this->db->setLBInfo( 'readOnlyReason', $params['readOnlyReason'] );
  63                 }
  64         }
  65
  66         /**
  67          * @param IDatabase $db Live connection handle
  68          * @param array $params Parameter map to LoadBalancerSingle::__constructs()
  69          * @return LoadBalancerSingle
  70          * @since 1.28
  71          */
  72         public static function newFromConnection( IDatabase $db, array $params = [] ) {
  73                 return new static( [ 'connection' => $db ] + $params );
  74         }
  75
  76         protected function reallyOpenConnection( array $server, $dbNameOverride = false ) {
  77                 return $this->db;
  78         }
  79 }
  80
  81 class_alias( 'Wikimedia\Rdbms\LoadBalancerSingle', 'LoadBalancerSingle' );