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 in the
  26  * directory given by $wgCacheDirectory. If $wgCacheDirectory is not set, this
  27  * will throw an exception.
  28  *
  29  * Profiling indicates that on Linux, this implementation outperforms MySQL if
  30  * the directory is on a local filesystem and there is ample kernel cache
  31  * space. The performance advantage is greater when the DBA extension is
  32  * available than it is with the PHP port.
  33  *
  34  * See Cdb.php and https://cr.yp.to/cdb.html
  35  */
  36 class LCStoreCDB implements LCStore {
  37
  38         /** @var Reader[] */
  39         private $readers;
  40
  41         /** @var Writer */
  42         private $writer;
  43
  44         /** @var string Current language code */
  45         private $currentLang;
  46
  47         /** @var bool|string Cache directory. False if not set */
  48         private $directory;
  49
  50         function __construct( $conf = [] ) {
  51                 global $wgCacheDirectory;
  52
  53                 if ( isset( $conf['directory'] ) ) {
  54                         $this->directory = $conf['directory'];
  55                 } else {
  56                         $this->directory = $wgCacheDirectory;
  57                 }
  58         }
  59
  60         public function get( $code, $key ) {
  61                 if ( !isset( $this->readers[$code] ) ) {
  62                         $fileName = $this->getFileName( $code );
  63
  64                         $this->readers[$code] = false;
  65                         if ( file_exists( $fileName ) ) {
  66                                 try {
  67                                         $this->readers[$code] = Reader::open( $fileName );
  68                                 } catch ( Exception $e ) {
  69                                         wfDebug( __METHOD__ . ": unable to open cdb file for reading\n" );
  70                                 }
  71                         }
  72                 }
  73
  74                 if ( !$this->readers[$code] ) {
  75                         return null;
  76                 } else {
  77                         $value = false;
  78                         try {
  79                                 $value = $this->readers[$code]->get( $key );
  80                         } catch ( Exception $e ) {
  81                                 wfDebug( __METHOD__ . ": \Cdb\Exception caught, error message was "
  82                                         . $e->getMessage() . "\n" );
  83                         }
  84                         if ( $value === false ) {
  85                                 return null;
  86                         }
  87
  88                         return unserialize( $value );
  89                 }
  90         }
  91
  92         public function startWrite( $code ) {
  93                 if ( !file_exists( $this->directory ) ) {
  94                         if ( !wfMkdirParents( $this->directory, null, __METHOD__ ) ) {
  95                                 throw new MWException( "Unable to create the localisation store " .
  96                                         "directory \"{$this->directory}\"" );
  97                         }
  98                 }
  99
 100                 // Close reader to stop permission errors on write
 101                 if ( !empty( $this->readers[$code] ) ) {
 102                         $this->readers[$code]->close();
 103                 }
 104
 105                 try {
 106                         $this->writer = Writer::open( $this->getFileName( $code ) );
 107                 } catch ( Exception $e ) {
 108                         throw new MWException( $e->getMessage() );
 109                 }
 110                 $this->currentLang = $code;
 111         }
 112
 113         public function finishWrite() {
 114                 // Close the writer
 115                 try {
 116                         $this->writer->close();
 117                 } catch ( Exception $e ) {
 118                         throw new MWException( $e->getMessage() );
 119                 }
 120                 $this->writer = null;
 121                 unset( $this->readers[$this->currentLang] );
 122                 $this->currentLang = null;
 123         }
 124
 125         public function set( $key, $value ) {
 126                 if ( is_null( $this->writer ) ) {
 127                         throw new MWException( __CLASS__ . ': must call startWrite() before calling set()' );
 128                 }
 129                 try {
 130                         $this->writer->set( $key, serialize( $value ) );
 131                 } catch ( Exception $e ) {
 132                         throw new MWException( $e->getMessage() );
 133                 }
 134         }
 135
 136         protected function getFileName( $code ) {
 137                 if ( strval( $code ) === '' || strpos( $code, '/' ) !== false ) {
 138                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
 139                 }
 140
 141                 return "{$this->directory}/l10n_cache-$code.cdb";
 142         }
 143
 144 }