includes/cache/localisation/LCStoreCDB.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 use Cdb\Exception;
  21 use Cdb\Reader;
  22 use Cdb\Writer;
  23
  24 /**
  25  * LCStore implementation which stores data as a collection of CDB files.
  26  *
  27  * Profiling indicates that on Linux, this implementation outperforms MySQL if
  28  * the directory is on a local filesystem and there is ample kernel cache
  29  * space. The performance advantage is greater when the DBA extension is
  30  * available than it is with the PHP port.
  31  *
  32  * See Cdb.php and https://cr.yp.to/cdb.html
  33  */
  34 class LCStoreCDB implements LCStore {
  35
  36         /** @var Reader[] */
  37         private $readers;
  38
  39         /** @var Writer */
  40         private $writer;
  41
  42         /** @var string Current language code */
  43         private $currentLang;
  44
  45         /** @var bool|string Cache directory. False if not set */
  46         private $directory;
  47
  48         function __construct( $conf = [] ) {
  49                 global $wgCacheDirectory;
  50
  51                 $this->directory = $conf['directory'] ?? $wgCacheDirectory;
  52         }
  53
  54         public function get( $code, $key ) {
  55                 if ( !isset( $this->readers[$code] ) ) {
  56                         $fileName = $this->getFileName( $code );
  57
  58                         $this->readers[$code] = false;
  59                         if ( file_exists( $fileName ) ) {
  60                                 try {
  61                                         $this->readers[$code] = Reader::open( $fileName );
  62                                 } catch ( Exception $e ) {
  63                                         wfDebug( __METHOD__ . ": unable to open cdb file for reading\n" );
  64                                 }
  65                         }
  66                 }
  67
  68                 if ( !$this->readers[$code] ) {
  69                         return null;
  70                 } else {
  71                         $value = false;
  72                         try {
  73                                 $value = $this->readers[$code]->get( $key );
  74                         } catch ( Exception $e ) {
  75                                 wfDebug( __METHOD__ . ": \Cdb\Exception caught, error message was "
  76                                         . $e->getMessage() . "\n" );
  77                         }
  78                         if ( $value === false ) {
  79                                 return null;
  80                         }
  81
  82                         return unserialize( $value );
  83                 }
  84         }
  85
  86         public function startWrite( $code ) {
  87                 if ( !file_exists( $this->directory ) && !wfMkdirParents( $this->directory, null, __METHOD__ ) ) {
  88                         throw new MWException( "Unable to create the localisation store " .
  89                                 "directory \"{$this->directory}\"" );
  90                 }
  91
  92                 // Close reader to stop permission errors on write
  93                 if ( !empty( $this->readers[$code] ) ) {
  94                         $this->readers[$code]->close();
  95                 }
  96
  97                 try {
  98                         $this->writer = Writer::open( $this->getFileName( $code ) );
  99                 } catch ( Exception $e ) {
 100                         throw new MWException( $e->getMessage() );
 101                 }
 102                 $this->currentLang = $code;
 103         }
 104
 105         public function finishWrite() {
 106                 // Close the writer
 107                 try {
 108                         $this->writer->close();
 109                 } catch ( Exception $e ) {
 110                         throw new MWException( $e->getMessage() );
 111                 }
 112                 $this->writer = null;
 113                 unset( $this->readers[$this->currentLang] );
 114                 $this->currentLang = null;
 115         }
 116
 117         public function set( $key, $value ) {
 118                 if ( is_null( $this->writer ) ) {
 119                         throw new MWException( __CLASS__ . ': must call startWrite() before calling set()' );
 120                 }
 121                 try {
 122                         $this->writer->set( $key, serialize( $value ) );
 123                 } catch ( Exception $e ) {
 124                         throw new MWException( $e->getMessage() );
 125                 }
 126         }
 127
 128         protected function getFileName( $code ) {
 129                 if ( strval( $code ) === '' || strpos( $code, '/' ) !== false ) {
 130                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
 131                 }
 132
 133                 return "{$this->directory}/l10n_cache-$code.cdb";
 134         }
 135
 136 }