includes/cache/localisation/LCStoreDB.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  */
  20
  21 use Wikimedia\Rdbms\Database;
  22 use Wikimedia\Rdbms\IDatabase;
  23 use Wikimedia\Rdbms\DBQueryError;
  24
  25 /**
  26  * LCStore implementation which uses the standard DB functions to store data.
  27  * This will work on any MediaWiki installation.
  28  */
  29 class LCStoreDB implements LCStore {
  30         /** @var string */
  31         private $currentLang;
  32         /** @var bool */
  33         private $writesDone = false;
  34         /** @var IDatabase|null */
  35         private $dbw;
  36         /** @var array */
  37         private $batch = [];
  38         /** @var bool */
  39         private $readOnly = false;
  40         /** @var array Server configuration map */
  41         private $server;
  42
  43         public function __construct( $params ) {
  44                 $this->server = $params['server'] ?? [];
  45         }
  46
  47         public function get( $code, $key ) {
  48                 if ( $this->server || $this->writesDone ) {
  49                         // If a server configuration map is specified, always used that connection
  50                         // for reads and writes. Otherwise, if writes occurred in finishWrite(), make
  51                         // sure those changes are always visible.
  52                         $db = $this->getWriteConnection();
  53                 } else {
  54                         $db = wfGetDB( DB_REPLICA );
  55                 }
  56
  57                 $value = $db->selectField(
  58                         'l10n_cache',
  59                         'lc_value',
  60                         [ 'lc_lang' => $code, 'lc_key' => $key ],
  61                         __METHOD__
  62                 );
  63
  64                 return ( $value !== false ) ? unserialize( $db->decodeBlob( $value ) ) : null;
  65         }
  66
  67         public function startWrite( $code ) {
  68                 if ( $this->readOnly ) {
  69                         return;
  70                 } elseif ( !$code ) {
  71                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
  72                 }
  73
  74                 $dbw = $this->getWriteConnection();
  75                 $this->readOnly = $dbw->isReadOnly();
  76
  77                 $this->currentLang = $code;
  78                 $this->batch = [];
  79         }
  80
  81         public function finishWrite() {
  82                 if ( $this->readOnly ) {
  83                         return;
  84                 } elseif ( is_null( $this->currentLang ) ) {
  85                         throw new MWException( __CLASS__ . ': must call startWrite() before finishWrite()' );
  86                 }
  87
  88                 $dbw = $this->getWriteConnection();
  89                 $dbw->startAtomic( __METHOD__ );
  90                 try {
  91                         $dbw->delete( 'l10n_cache', [ 'lc_lang' => $this->currentLang ], __METHOD__ );
  92                         foreach ( array_chunk( $this->batch, 500 ) as $rows ) {
  93                                 $dbw->insert( 'l10n_cache', $rows, __METHOD__ );
  94                         }
  95                         $this->writesDone = true;
  96                 } catch ( DBQueryError $e ) {
  97                         if ( $dbw->wasReadOnlyError() ) {
  98                                 $this->readOnly = true; // just avoid site down time
  99                         } else {
 100                                 throw $e;
 101                         }
 102                 }
 103                 $dbw->endAtomic( __METHOD__ );
 104
 105                 $this->currentLang = null;
 106                 $this->batch = [];
 107         }
 108
 109         public function set( $key, $value ) {
 110                 if ( $this->readOnly ) {
 111                         return;
 112                 } elseif ( is_null( $this->currentLang ) ) {
 113                         throw new MWException( __CLASS__ . ': must call startWrite() before set()' );
 114                 }
 115
 116                 $dbw = $this->getWriteConnection();
 117
 118                 $this->batch[] = [
 119                         'lc_lang' => $this->currentLang,
 120                         'lc_key' => $key,
 121                         'lc_value' => $dbw->encodeBlob( serialize( $value ) )
 122                 ];
 123         }
 124
 125         /**
 126          * @return IDatabase
 127          */
 128         private function getWriteConnection() {
 129                 if ( !$this->dbw ) {
 130                         if ( $this->server ) {
 131                                 $this->dbw = Database::factory( $this->server['type'], $this->server );
 132                                 if ( !$this->dbw ) {
 133                                         throw new MWException( __CLASS__ . ': failed to obtain a DB connection' );
 134                                 }
 135                         } else {
 136                                 $this->dbw = wfGetDB( DB_MASTER );
 137                         }
 138                 }
 139
 140                 return $this->dbw;
 141         }
 142 }