includes/parser/CacheTime.php

   1 <?php
   2 /**
   3  * Parser cache specific expiry check.
   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 Parser
  22  */
  23
  24 /**
  25  * Parser cache specific expiry check.
  26  *
  27  * @ingroup Parser
  28  */
  29 class CacheTime {
  30         /** @var array|bool ParserOptions which have been taken into account to
  31          * produce output or false if not available.
  32          */
  33         public $mUsedOptions;
  34
  35         # Compatibility check
  36         public $mVersion = Parser::VERSION;
  37
  38         # Time when this object was generated, or -1 for uncacheable. Used in ParserCache.
  39         public $mCacheTime = '';
  40
  41         # Seconds after which the object should expire, use 0 for uncacheable. Used in ParserCache.
  42         public $mCacheExpiry = null;
  43
  44         # Revision ID that was parsed
  45         public $mCacheRevisionId = null;
  46
  47         /**
  48          * @return string TS_MW timestamp
  49          */
  50         public function getCacheTime() {
  51                 return wfTimestamp( TS_MW, $this->mCacheTime );
  52         }
  53
  54         /**
  55          * setCacheTime() sets the timestamp expressing when the page has been rendered.
  56          * This does not control expiry, see updateCacheExpiry() for that!
  57          * @param string $t TS_MW timestamp
  58          * @return string
  59          */
  60         public function setCacheTime( $t ) {
  61                 return wfSetVar( $this->mCacheTime, $t );
  62         }
  63
  64         /**
  65          * @since 1.23
  66          * @return int|null Revision id, if any was set
  67          */
  68         public function getCacheRevisionId() {
  69                 return $this->mCacheRevisionId;
  70         }
  71
  72         /**
  73          * @since 1.23
  74          * @param int $id Revision id
  75          */
  76         public function setCacheRevisionId( $id ) {
  77                 $this->mCacheRevisionId = $id;
  78         }
  79
  80         /**
  81          * Sets the number of seconds after which this object should expire.
  82          * This value is used with the ParserCache.
  83          * If called with a value greater than the value provided at any previous call,
  84          * the new call has no effect. The value returned by getCacheExpiry is smaller
  85          * or equal to the smallest number that was provided as an argument to
  86          * updateCacheExpiry().
  87          *
  88          * @param int $seconds
  89          */
  90         public function updateCacheExpiry( $seconds ) {
  91                 $seconds = (int)$seconds;
  92
  93                 if ( $this->mCacheExpiry === null || $this->mCacheExpiry > $seconds ) {
  94                         $this->mCacheExpiry = $seconds;
  95                 }
  96
  97                 // hack: set old-style marker for uncacheable entries.
  98                 if ( $this->mCacheExpiry !== null && $this->mCacheExpiry <= 0 ) {
  99                         $this->mCacheTime = -1;
 100                 }
 101         }
 102
 103         /**
 104          * Returns the number of seconds after which this object should expire.
 105          * This method is used by ParserCache to determine how long the ParserOutput can be cached.
 106          * The timestamp of expiry can be calculated by adding getCacheExpiry() to getCacheTime().
 107          * The value returned by getCacheExpiry is smaller or equal to the smallest number
 108          * that was provided to a call of updateCacheExpiry(), and smaller or equal to the
 109          * value of $wgParserCacheExpireTime.
 110          * @return int|mixed|null
 111          */
 112         public function getCacheExpiry() {
 113                 global $wgParserCacheExpireTime;
 114
 115                 if ( $this->mCacheTime < 0 ) {
 116                         return 0;
 117                 } // old-style marker for "not cacheable"
 118
 119                 $expire = $this->mCacheExpiry;
 120
 121                 if ( $expire === null ) {
 122                         $expire = $wgParserCacheExpireTime;
 123                 } else {
 124                         $expire = min( $expire, $wgParserCacheExpireTime );
 125                 }
 126
 127                 if ( $expire <= 0 ) {
 128                         return 0; // not cacheable
 129                 } else {
 130                         return $expire;
 131                 }
 132         }
 133
 134         /**
 135          * @return bool
 136          */
 137         public function isCacheable() {
 138                 return $this->getCacheExpiry() > 0;
 139         }
 140
 141         /**
 142          * Return true if this cached output object predates the global or
 143          * per-article cache invalidation timestamps, or if it comes from
 144          * an incompatible older version.
 145          *
 146          * @param string $touched The affected article's last touched timestamp
 147          * @return bool
 148          */
 149         public function expired( $touched ) {
 150                 global $wgCacheEpoch;
 151
 152                 return !$this->isCacheable() // parser says it's uncacheable
 153                         || $this->getCacheTime() < $touched
 154                         || $this->getCacheTime() <= $wgCacheEpoch
 155                         || $this->getCacheTime() <
 156                                 wfTimestamp( TS_MW, time() - $this->getCacheExpiry() ) // expiry period has passed
 157                         || !isset( $this->mVersion )
 158                         || version_compare( $this->mVersion, Parser::VERSION, "lt" );
 159         }
 160
 161         /**
 162          * Return true if this cached output object is for a different revision of
 163          * the page.
 164          *
 165          * @todo We always return false if $this->getCacheRevisionId() is null;
 166          * this prevents invalidating the whole parser cache when this change is
 167          * deployed. Someday that should probably be changed.
 168          *
 169          * @since 1.23
 170          * @param int $id The affected article's current revision id
 171          * @return bool
 172          */
 173         public function isDifferentRevision( $id ) {
 174                 $cached = $this->getCacheRevisionId();
 175                 return $cached !== null && $id !== $cached;
 176         }
 177 }