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 string Cache directory */
  46         private $directory;
  47
  48         function __construct( $conf = [] ) {
  49                 $this->directory = $conf['directory'];
  50         }
  51
  52         public function get( $code, $key ) {
  53                 if ( !isset( $this->readers[$code] ) ) {
  54                         $fileName = $this->getFileName( $code );
  55
  56                         $this->readers[$code] = false;
  57                         if ( file_exists( $fileName ) ) {
  58                                 try {
  59                                         $this->readers[$code] = Reader::open( $fileName );
  60                                 } catch ( Exception $e ) {
  61                                         wfDebug( __METHOD__ . ": unable to open cdb file for reading\n" );
  62                                 }
  63                         }
  64                 }
  65
  66                 if ( !$this->readers[$code] ) {
  67                         return null;
  68                 } else {
  69                         $value = false;
  70                         try {
  71                                 $value = $this->readers[$code]->get( $key );
  72                         } catch ( Exception $e ) {
  73                                 wfDebug( __METHOD__ . ": \Cdb\Exception caught, error message was "
  74                                         . $e->getMessage() . "\n" );
  75                         }
  76                         if ( $value === false ) {
  77                                 return null;
  78                         }
  79
  80                         return unserialize( $value );
  81                 }
  82         }
  83
  84         public function startWrite( $code ) {
  85                 if ( !file_exists( $this->directory ) && !wfMkdirParents( $this->directory, null, __METHOD__ ) ) {
  86                         throw new MWException( "Unable to create the localisation store " .
  87                                 "directory \"{$this->directory}\"" );
  88                 }
  89
  90                 // Close reader to stop permission errors on write
  91                 if ( !empty( $this->readers[$code] ) ) {
  92                         $this->readers[$code]->close();
  93                 }
  94
  95                 try {
  96                         $this->writer = Writer::open( $this->getFileName( $code ) );
  97                 } catch ( Exception $e ) {
  98                         throw new MWException( $e->getMessage() );
  99                 }
 100                 $this->currentLang = $code;
 101         }
 102
 103         public function finishWrite() {
 104                 // Close the writer
 105                 try {
 106                         $this->writer->close();
 107                 } catch ( Exception $e ) {
 108                         throw new MWException( $e->getMessage() );
 109                 }
 110                 $this->writer = null;
 111                 unset( $this->readers[$this->currentLang] );
 112                 $this->currentLang = null;
 113         }
 114
 115         public function set( $key, $value ) {
 116                 if ( is_null( $this->writer ) ) {
 117                         throw new MWException( __CLASS__ . ': must call startWrite() before calling set()' );
 118                 }
 119                 try {
 120                         $this->writer->set( $key, serialize( $value ) );
 121                 } catch ( Exception $e ) {
 122                         throw new MWException( $e->getMessage() );
 123                 }
 124         }
 125
 126         protected function getFileName( $code ) {
 127                 if ( strval( $code ) === '' || strpos( $code, '/' ) !== false ) {
 128                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
 129                 }
 130
 131                 return "{$this->directory}/l10n_cache-$code.cdb";
 132         }
 133
 134 }