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         /**
  31          * @var string[] ParserOptions which have been taken into account to produce output.
  32          */
  33         public $mUsedOptions;
  34
  35         /**
  36          * @var string|null Compatibility check
  37          */
  38         public $mVersion = Parser::VERSION;
  39
  40         /**
  41          * @var string|int TS_MW timestamp when this object was generated, or -1 for uncacheable. Used
  42          * in ParserCache.
  43          */
  44         public $mCacheTime = '';
  45
  46         /**
  47          * @var int|null Seconds after which the object should expire, use 0 for uncacheable. Used in
  48          * ParserCache.
  49          */
  50         public $mCacheExpiry = null;
  51
  52         /**
  53          * @var int|null Revision ID that was parsed
  54          */
  55         public $mCacheRevisionId = null;
  56
  57         /**
  58          * @return string TS_MW timestamp
  59          */
  60         public function getCacheTime() {
  61                 return wfTimestamp( TS_MW, $this->mCacheTime );
  62         }
  63
  64         /**
  65          * setCacheTime() sets the timestamp expressing when the page has been rendered.
  66          * This does not control expiry, see updateCacheExpiry() for that!
  67          * @param string $t TS_MW timestamp
  68          * @return string
  69          */
  70         public function setCacheTime( $t ) {
  71                 return wfSetVar( $this->mCacheTime, $t );
  72         }
  73
  74         /**
  75          * @since 1.23
  76          * @return int|null Revision id, if any was set
  77          */
  78         public function getCacheRevisionId() {
  79                 return $this->mCacheRevisionId;
  80         }
  81
  82         /**
  83          * @since 1.23
  84          * @param int|null $id Revision ID
  85          */
  86         public function setCacheRevisionId( $id ) {
  87                 $this->mCacheRevisionId = $id;
  88         }
  89
  90         /**
  91          * Sets the number of seconds after which this object should expire.
  92          *
  93          * This value is used with the ParserCache.
  94          * If called with a value greater than the value provided at any previous call,
  95          * the new call has no effect. The value returned by getCacheExpiry is smaller
  96          * or equal to the smallest number that was provided as an argument to
  97          * updateCacheExpiry().
  98          *
  99          * Avoid using 0 if at all possible. Consider JavaScript for highly dynamic content.
 100          *
 101          * @param int $seconds
 102          */
 103         public function updateCacheExpiry( $seconds ) {
 104                 $seconds = (int)$seconds;
 105
 106                 if ( $this->mCacheExpiry === null || $this->mCacheExpiry > $seconds ) {
 107                         $this->mCacheExpiry = $seconds;
 108                 }
 109         }
 110
 111         /**
 112          * Returns the number of seconds after which this object should expire.
 113          * This method is used by ParserCache to determine how long the ParserOutput can be cached.
 114          * The timestamp of expiry can be calculated by adding getCacheExpiry() to getCacheTime().
 115          * The value returned by getCacheExpiry is smaller or equal to the smallest number
 116          * that was provided to a call of updateCacheExpiry(), and smaller or equal to the
 117          * value of $wgParserCacheExpireTime.
 118          * @return int
 119          */
 120         public function getCacheExpiry() {
 121                 global $wgParserCacheExpireTime;
 122
 123                 if ( $this->mCacheTime < 0 ) {
 124                         return 0;
 125                 } // old-style marker for "not cacheable"
 126
 127                 $expire = $this->mCacheExpiry;
 128
 129                 if ( $expire === null ) {
 130                         $expire = $wgParserCacheExpireTime;
 131                 } else {
 132                         $expire = min( $expire, $wgParserCacheExpireTime );
 133                 }
 134
 135                 if ( $expire <= 0 ) {
 136                         return 0; // not cacheable
 137                 } else {
 138                         return $expire;
 139                 }
 140         }
 141
 142         /**
 143          * @return bool
 144          */
 145         public function isCacheable() {
 146                 return $this->getCacheExpiry() > 0;
 147         }
 148
 149         /**
 150          * Return true if this cached output object predates the global or
 151          * per-article cache invalidation timestamps, or if it comes from
 152          * an incompatible older version.
 153          *
 154          * @param string $touched The affected article's last touched timestamp
 155          * @return bool
 156          */
 157         public function expired( $touched ) {
 158                 global $wgCacheEpoch;
 159
 160                 return !$this->isCacheable() // parser says it's uncacheable
 161                         || $this->getCacheTime() < $touched
 162                         || $this->getCacheTime() <= $wgCacheEpoch
 163                         || $this->getCacheTime() <
 164                                 wfTimestamp( TS_MW, time() - $this->getCacheExpiry() ) // expiry period has passed
 165                         || !isset( $this->mVersion )
 166                         || version_compare( $this->mVersion, Parser::VERSION, "lt" );
 167         }
 168
 169         /**
 170          * Return true if this cached output object is for a different revision of
 171          * the page.
 172          *
 173          * @todo We always return false if $this->getCacheRevisionId() is null;
 174          * this prevents invalidating the whole parser cache when this change is
 175          * deployed. Someday that should probably be changed.
 176          *
 177          * @since 1.23
 178          * @param int $id The affected article's current revision id
 179          * @return bool
 180          */
 181         public function isDifferentRevision( $id ) {
 182                 $cached = $this->getCacheRevisionId();
 183                 return $cached !== null && $id !== $cached;
 184         }
 185 }