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 Language code */
  31         private $code;
  32         /** @var array Server configuration map */
  33         private $server;
  34
  35         /** @var array Rows buffered for insertion */
  36         private $batch = [];
  37
  38         /** @var IDatabase|null */
  39         private $dbw;
  40         /** @var bool Whether a batch of writes were recently written */
  41         private $writesDone = false;
  42         /** @var bool Whether the DB is read-only or otherwise unavailable for writes */
  43         private $readOnly = false;
  44
  45         public function __construct( $params ) {
  46                 $this->server = $params['server'] ?? [];
  47         }
  48
  49         public function get( $code, $key ) {
  50                 if ( $this->server || $this->writesDone ) {
  51                         // If a server configuration map is specified, always used that connection
  52                         // for reads and writes. Otherwise, if writes occurred in finishWrite(), make
  53                         // sure those changes are always visible.
  54                         $db = $this->getWriteConnection();
  55                 } else {
  56                         $db = wfGetDB( DB_REPLICA );
  57                 }
  58
  59                 $value = $db->selectField(
  60                         'l10n_cache',
  61                         'lc_value',
  62                         [ 'lc_lang' => $code, 'lc_key' => $key ],
  63                         __METHOD__
  64                 );
  65
  66                 return ( $value !== false ) ? unserialize( $db->decodeBlob( $value ) ) : null;
  67         }
  68
  69         public function startWrite( $code ) {
  70                 if ( $this->readOnly ) {
  71                         return;
  72                 } elseif ( !$code ) {
  73                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
  74                 }
  75
  76                 $dbw = $this->getWriteConnection();
  77                 $this->readOnly = $dbw->isReadOnly();
  78
  79                 $this->code = $code;
  80                 $this->batch = [];
  81         }
  82
  83         public function finishWrite() {
  84                 if ( $this->readOnly ) {
  85                         return;
  86                 } elseif ( is_null( $this->code ) ) {
  87                         throw new MWException( __CLASS__ . ': must call startWrite() before finishWrite()' );
  88                 }
  89
  90                 $trxProfiler = Profiler::instance()->getTransactionProfiler();
  91                 $oldSilenced = $trxProfiler->setSilenced( true );
  92                 try {
  93                         $dbw = $this->getWriteConnection();
  94                         $dbw->startAtomic( __METHOD__ );
  95                         try {
  96                                 $dbw->delete( 'l10n_cache', [ 'lc_lang' => $this->code ], __METHOD__ );
  97                                 foreach ( array_chunk( $this->batch, 500 ) as $rows ) {
  98                                         $dbw->insert( 'l10n_cache', $rows, __METHOD__ );
  99                                 }
 100                                 $this->writesDone = true;
 101                         } catch ( DBQueryError $e ) {
 102                                 if ( $dbw->wasReadOnlyError() ) {
 103                                         $this->readOnly = true; // just avoid site down time
 104                                 } else {
 105                                         throw $e;
 106                                 }
 107                         }
 108                         $dbw->endAtomic( __METHOD__ );
 109                 } finally {
 110                         $trxProfiler->setSilenced( $oldSilenced );
 111                 }
 112
 113                 $this->code = null;
 114                 $this->batch = [];
 115         }
 116
 117         public function set( $key, $value ) {
 118                 if ( $this->readOnly ) {
 119                         return;
 120                 } elseif ( is_null( $this->code ) ) {
 121                         throw new MWException( __CLASS__ . ': must call startWrite() before set()' );
 122                 }
 123
 124                 $dbw = $this->getWriteConnection();
 125
 126                 $this->batch[] = [
 127                         'lc_lang' => $this->code,
 128                         'lc_key' => $key,
 129                         'lc_value' => $dbw->encodeBlob( serialize( $value ) )
 130                 ];
 131         }
 132
 133         /**
 134          * @return IDatabase
 135          */
 136         private function getWriteConnection() {
 137                 if ( !$this->dbw ) {
 138                         if ( $this->server ) {
 139                                 $this->dbw = Database::factory( $this->server['type'], $this->server );
 140                                 if ( !$this->dbw ) {
 141                                         throw new MWException( __CLASS__ . ': failed to obtain a DB connection' );
 142                                 }
 143                         } else {
 144                                 $this->dbw = wfGetDB( DB_MASTER );
 145                         }
 146                 }
 147
 148                 return $this->dbw;
 149         }
 150 }