includes/cache/dependency/FileDependency.php

   1 <?php
   2 /**
   3  * Data caching with dependencies.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Cache
  22  */
  23
  24 /**
  25  * @ingroup Cache
  26  */
  27 class FileDependency extends CacheDependency {
  28         private $filename;
  29         private $timestamp;
  30
  31         /**
  32          * Create a file dependency
  33          *
  34          * @param string $filename The name of the file, preferably fully qualified
  35          * @param null|bool|int $timestamp The unix last modified timestamp, or false if the
  36          *        file does not exist. If omitted, the timestamp will be loaded from
  37          *        the file.
  38          *
  39          * A dependency on a nonexistent file will be triggered when the file is
  40          * created. A dependency on an existing file will be triggered when the
  41          * file is changed.
  42          */
  43         function __construct( $filename, $timestamp = null ) {
  44                 $this->filename = $filename;
  45                 $this->timestamp = $timestamp;
  46         }
  47
  48         /**
  49          * @return array
  50          */
  51         function __sleep() {
  52                 $this->loadDependencyValues();
  53
  54                 return [ 'filename', 'timestamp' ];
  55         }
  56
  57         function loadDependencyValues() {
  58                 if ( is_null( $this->timestamp ) ) {
  59                         Wikimedia\suppressWarnings();
  60                         # Dependency on a non-existent file stores "false"
  61                         # This is a valid concept!
  62                         $this->timestamp = filemtime( $this->filename );
  63                         Wikimedia\restoreWarnings();
  64                 }
  65         }
  66
  67         /**
  68          * @return bool
  69          */
  70         function isExpired() {
  71                 Wikimedia\suppressWarnings();
  72                 $lastmod = filemtime( $this->filename );
  73                 Wikimedia\restoreWarnings();
  74                 if ( $lastmod === false ) {
  75                         if ( $this->timestamp === false ) {
  76                                 # Still nonexistent
  77                                 return false;
  78                         }
  79
  80                         # Deleted
  81                         wfDebug( "Dependency triggered: {$this->filename} deleted.\n" );
  82
  83                         return true;
  84                 }
  85
  86                 if ( $lastmod > $this->timestamp ) {
  87                         # Modified or created
  88                         wfDebug( "Dependency triggered: {$this->filename} changed.\n" );
  89
  90                         return true;
  91                 }
  92
  93                 # Not modified
  94                 return false;
  95         }
  96 }