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     $mVersion = Parser::VERSION,  # Compatibility check
  32                 $mCacheTime = '',             # Time when this object was generated, or -1 for uncacheable. Used in ParserCache.
  33                 $mCacheExpiry = null,         # Seconds after which the object should expire, use 0 for uncachable. Used in ParserCache.
  34                 $mContainsOldMagic;           # Boolean variable indicating if the input contained variables like {{CURRENTDAY}}
  35
  36         function getCacheTime()              { return $this->mCacheTime; }
  37
  38         function containsOldMagic()          { return $this->mContainsOldMagic; }
  39         function setContainsOldMagic( $com ) { return wfSetVar( $this->mContainsOldMagic, $com ); }
  40
  41         /**
  42          * setCacheTime() sets the timestamp expressing when the page has been rendered.
  43          * This doesn not control expiry, see updateCacheExpiry() for that!
  44          * @param $t string
  45          * @return string
  46          */
  47         function setCacheTime( $t )          { return wfSetVar( $this->mCacheTime, $t ); }
  48
  49         /**
  50          * Sets the number of seconds after which this object should expire.
  51          * This value is used with the ParserCache.
  52          * If called with a value greater than the value provided at any previous call,
  53          * the new call has no effect. The value returned by getCacheExpiry is smaller
  54          * or equal to the smallest number that was provided as an argument to
  55          * updateCacheExpiry().
  56          *
  57          * @param $seconds number
  58          */
  59         function updateCacheExpiry( $seconds ) {
  60                 $seconds = (int)$seconds;
  61
  62                 if ( $this->mCacheExpiry === null || $this->mCacheExpiry > $seconds ) {
  63                         $this->mCacheExpiry = $seconds;
  64                 }
  65
  66                 // hack: set old-style marker for uncacheable entries.
  67                 if ( $this->mCacheExpiry !== null && $this->mCacheExpiry <= 0 ) {
  68                         $this->mCacheTime = -1;
  69                 }
  70         }
  71
  72         /**
  73          * Returns the number of seconds after which this object should expire.
  74          * This method is used by ParserCache to determine how long the ParserOutput can be cached.
  75          * The timestamp of expiry can be calculated by adding getCacheExpiry() to getCacheTime().
  76          * The value returned by getCacheExpiry is smaller or equal to the smallest number
  77          * that was provided to a call of updateCacheExpiry(), and smaller or equal to the
  78          * value of $wgParserCacheExpireTime.
  79          * @return int|mixed|null
  80          */
  81         function getCacheExpiry() {
  82                 global $wgParserCacheExpireTime;
  83
  84                 if ( $this->mCacheTime < 0 ) {
  85                         return 0;
  86                 } // old-style marker for "not cachable"
  87
  88                 $expire = $this->mCacheExpiry;
  89
  90                 if ( $expire === null ) {
  91                         $expire = $wgParserCacheExpireTime;
  92                 } else {
  93                         $expire = min( $expire, $wgParserCacheExpireTime );
  94                 }
  95
  96                 if ( $this->containsOldMagic() ) { //compatibility hack
  97                         $expire = min( $expire, 3600 ); # 1 hour
  98                 }
  99
 100                 if ( $expire <= 0 ) {
 101                         return 0; // not cachable
 102                 } else {
 103                         return $expire;
 104                 }
 105         }
 106
 107         /**
 108          * @return bool
 109          */
 110         function isCacheable() {
 111                 return $this->getCacheExpiry() > 0;
 112         }
 113
 114         /**
 115          * Return true if this cached output object predates the global or
 116          * per-article cache invalidation timestamps, or if it comes from
 117          * an incompatible older version.
 118          *
 119          * @param string $touched the affected article's last touched timestamp
 120          * @return Boolean
 121          */
 122         public function expired( $touched ) {
 123                 global $wgCacheEpoch;
 124                 return !$this->isCacheable() || // parser says it's uncacheable
 125                         $this->getCacheTime() < $touched ||
 126                         $this->getCacheTime() <= $wgCacheEpoch ||
 127                         $this->getCacheTime() < wfTimestamp( TS_MW, time() - $this->getCacheExpiry() ) || // expiry period has passed
 128                         !isset( $this->mVersion ) ||
 129                         version_compare( $this->mVersion, Parser::VERSION, "lt" );
 130         }
 131
 132 }