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\IDatabase;
  22 use Wikimedia\Rdbms\DBQueryError;
  23
  24 /**
  25  * LCStore implementation which uses the standard DB functions to store data.
  26  * This will work on any MediaWiki installation.
  27  */
  28 class LCStoreDB implements LCStore {
  29
  30         /** @var string */
  31         private $currentLang;
  32         /** @var bool */
  33         private $writesDone = false;
  34         /** @var IDatabase */
  35         private $dbw;
  36         /** @var array */
  37         private $batch = [];
  38         /** @var bool */
  39         private $readOnly = false;
  40
  41         public function get( $code, $key ) {
  42                 if ( $this->writesDone && $this->dbw ) {
  43                         $db = $this->dbw; // see the changes in finishWrite()
  44                 } else {
  45                         $db = wfGetDB( DB_REPLICA );
  46                 }
  47
  48                 $value = $db->selectField(
  49                         'l10n_cache',
  50                         'lc_value',
  51                         [ 'lc_lang' => $code, 'lc_key' => $key ],
  52                         __METHOD__
  53                 );
  54
  55                 return ( $value !== false ) ? unserialize( $db->decodeBlob( $value ) ) : null;
  56         }
  57
  58         public function startWrite( $code ) {
  59                 if ( $this->readOnly ) {
  60                         return;
  61                 } elseif ( !$code ) {
  62                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
  63                 }
  64
  65                 $this->dbw = wfGetDB( DB_MASTER );
  66                 $this->readOnly = $this->dbw->isReadOnly();
  67
  68                 $this->currentLang = $code;
  69                 $this->batch = [];
  70         }
  71
  72         public function finishWrite() {
  73                 if ( $this->readOnly ) {
  74                         return;
  75                 } elseif ( is_null( $this->currentLang ) ) {
  76                         throw new MWException( __CLASS__ . ': must call startWrite() before finishWrite()' );
  77                 }
  78
  79                 $this->dbw->startAtomic( __METHOD__ );
  80                 try {
  81                         $this->dbw->delete(
  82                                 'l10n_cache',
  83                                 [ 'lc_lang' => $this->currentLang ],
  84                                 __METHOD__
  85                         );
  86                         foreach ( array_chunk( $this->batch, 500 ) as $rows ) {
  87                                 $this->dbw->insert( 'l10n_cache', $rows, __METHOD__ );
  88                         }
  89                         $this->writesDone = true;
  90                 } catch ( DBQueryError $e ) {
  91                         if ( $this->dbw->wasReadOnlyError() ) {
  92                                 $this->readOnly = true; // just avoid site down time
  93                         } else {
  94                                 throw $e;
  95                         }
  96                 }
  97                 $this->dbw->endAtomic( __METHOD__ );
  98
  99                 $this->currentLang = null;
 100                 $this->batch = [];
 101         }
 102
 103         public function set( $key, $value ) {
 104                 if ( $this->readOnly ) {
 105                         return;
 106                 } elseif ( is_null( $this->currentLang ) ) {
 107                         throw new MWException( __CLASS__ . ': must call startWrite() before set()' );
 108                 }
 109
 110                 $this->batch[] = [
 111                         'lc_lang' => $this->currentLang,
 112                         'lc_key' => $key,
 113                         'lc_value' => $this->dbw->encodeBlob( serialize( $value ) )
 114                 ];
 115         }
 116
 117 }