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