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
  21 /**
  22  * LCStore implementation which stores data as a collection of CDB files in the
  23  * directory given by $wgCacheDirectory. If $wgCacheDirectory is not set, this
  24  * will throw an exception.
  25  *
  26  * Profiling indicates that on Linux, this implementation outperforms MySQL if
  27  * the directory is on a local filesystem and there is ample kernel cache
  28  * space. The performance advantage is greater when the DBA extension is
  29  * available than it is with the PHP port.
  30  *
  31  * See Cdb.php and http://cr.yp.to/cdb.html
  32  */
  33 class LCStoreCDB implements LCStore {
  34
  35         /** @var CdbReader[] */
  36         private $readers;
  37
  38         /** @var CdbWriter */
  39         private $writer;
  40
  41         /** @var string Current language code */
  42         private $currentLang;
  43
  44         /** @var bool|string Cache directory. False if not set */
  45         private $directory;
  46
  47         function __construct( $conf = [] ) {
  48                 global $wgCacheDirectory;
  49
  50                 if ( isset( $conf['directory'] ) ) {
  51                         $this->directory = $conf['directory'];
  52                 } else {
  53                         $this->directory = $wgCacheDirectory;
  54                 }
  55         }
  56
  57         public function get( $code, $key ) {
  58                 if ( !isset( $this->readers[$code] ) ) {
  59                         $fileName = $this->getFileName( $code );
  60
  61                         $this->readers[$code] = false;
  62                         if ( file_exists( $fileName ) ) {
  63                                 try {
  64                                         $this->readers[$code] = CdbReader::open( $fileName );
  65                                 } catch ( CdbException $e ) {
  66                                         wfDebug( __METHOD__ . ": unable to open cdb file for reading\n" );
  67                                 }
  68                         }
  69                 }
  70
  71                 if ( !$this->readers[$code] ) {
  72                         return null;
  73                 } else {
  74                         $value = false;
  75                         try {
  76                                 $value = $this->readers[$code]->get( $key );
  77                         } catch ( CdbException $e ) {
  78                                 wfDebug( __METHOD__ . ": CdbException caught, error message was "
  79                                         . $e->getMessage() . "\n" );
  80                         }
  81                         if ( $value === false ) {
  82                                 return null;
  83                         }
  84
  85                         return unserialize( $value );
  86                 }
  87         }
  88
  89         public function startWrite( $code ) {
  90                 if ( !file_exists( $this->directory ) ) {
  91                         if ( !wfMkdirParents( $this->directory, null, __METHOD__ ) ) {
  92                                 throw new MWException( "Unable to create the localisation store " .
  93                                         "directory \"{$this->directory}\"" );
  94                         }
  95                 }
  96
  97                 // Close reader to stop permission errors on write
  98                 if ( !empty( $this->readers[$code] ) ) {
  99                         $this->readers[$code]->close();
 100                 }
 101
 102                 try {
 103                         $this->writer = CdbWriter::open( $this->getFileName( $code ) );
 104                 } catch ( CdbException $e ) {
 105                         throw new MWException( $e->getMessage() );
 106                 }
 107                 $this->currentLang = $code;
 108         }
 109
 110         public function finishWrite() {
 111                 // Close the writer
 112                 try {
 113                         $this->writer->close();
 114                 } catch ( CdbException $e ) {
 115                         throw new MWException( $e->getMessage() );
 116                 }
 117                 $this->writer = null;
 118                 unset( $this->readers[$this->currentLang] );
 119                 $this->currentLang = null;
 120         }
 121
 122         public function set( $key, $value ) {
 123                 if ( is_null( $this->writer ) ) {
 124                         throw new MWException( __CLASS__ . ': must call startWrite() before calling set()' );
 125                 }
 126                 try {
 127                         $this->writer->set( $key, serialize( $value ) );
 128                 } catch ( CdbException $e ) {
 129                         throw new MWException( $e->getMessage() );
 130                 }
 131         }
 132
 133         protected function getFileName( $code ) {
 134                 if ( strval( $code ) === '' || strpos( $code, '/' ) !== false ) {
 135                         throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
 136                 }
 137
 138                 return "{$this->directory}/l10n_cache-$code.cdb";
 139         }
 140
 141 }