includes/parser/CacheTime.php

   1 <?php
   2
   3 /**
   4  * @todo document
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19  * http://www.gnu.org/copyleft/gpl.html
  20  *
  21  * @file
  22  * @ingroup Parser
  23  */
  24 class CacheTime {
  25
  26         var     $mVersion = Parser::VERSION,  # Compatibility check
  27                 $mCacheTime = '',             # Time when this object was generated, or -1 for uncacheable. Used in ParserCache.
  28                 $mCacheExpiry = null,         # Seconds after which the object should expire, use 0 for uncachable. Used in ParserCache.
  29                 $mContainsOldMagic;           # Boolean variable indicating if the input contained variables like {{CURRENTDAY}}
  30
  31         function getCacheTime()              { return $this->mCacheTime; }
  32
  33         function containsOldMagic()          { return $this->mContainsOldMagic; }
  34         function setContainsOldMagic( $com ) { return wfSetVar( $this->mContainsOldMagic, $com ); }
  35
  36         /**
  37          * setCacheTime() sets the timestamp expressing when the page has been rendered.
  38          * This doesn not control expiry, see updateCacheExpiry() for that!
  39          * @param $t string
  40          * @return string
  41          */
  42         function setCacheTime( $t )          { return wfSetVar( $this->mCacheTime, $t ); }
  43
  44         /**
  45          * Sets the number of seconds after which this object should expire.
  46          * This value is used with the ParserCache.
  47          * If called with a value greater than the value provided at any previous call,
  48          * the new call has no effect. The value returned by getCacheExpiry is smaller
  49          * or equal to the smallest number that was provided as an argument to
  50          * updateCacheExpiry().
  51          *
  52          * @param $seconds number
  53          */
  54         function updateCacheExpiry( $seconds ) {
  55                 $seconds = (int)$seconds;
  56
  57                 if ( $this->mCacheExpiry === null || $this->mCacheExpiry > $seconds ) {
  58                         $this->mCacheExpiry = $seconds;
  59                 }
  60
  61                 // hack: set old-style marker for uncacheable entries.
  62                 if ( $this->mCacheExpiry !== null && $this->mCacheExpiry <= 0 ) {
  63                         $this->mCacheTime = -1;
  64                 }
  65         }
  66
  67         /**
  68          * Returns the number of seconds after which this object should expire.
  69          * This method is used by ParserCache to determine how long the ParserOutput can be cached.
  70          * The timestamp of expiry can be calculated by adding getCacheExpiry() to getCacheTime().
  71          * The value returned by getCacheExpiry is smaller or equal to the smallest number
  72          * that was provided to a call of updateCacheExpiry(), and smaller or equal to the
  73          * value of $wgParserCacheExpireTime.
  74          * @return int|mixed|null
  75          */
  76         function getCacheExpiry() {
  77                 global $wgParserCacheExpireTime;
  78
  79                 if ( $this->mCacheTime < 0 ) {
  80                         return 0;
  81                 } // old-style marker for "not cachable"
  82
  83                 $expire = $this->mCacheExpiry;
  84
  85                 if ( $expire === null ) {
  86                         $expire = $wgParserCacheExpireTime;
  87                 } else {
  88                         $expire = min( $expire, $wgParserCacheExpireTime );
  89                 }
  90
  91                 if( $this->containsOldMagic() ) { //compatibility hack
  92                         $expire = min( $expire, 3600 ); # 1 hour
  93                 }
  94
  95                 if ( $expire <= 0 ) {
  96                         return 0; // not cachable
  97                 } else {
  98                         return $expire;
  99                 }
 100         }
 101
 102         /**
 103          * @return bool
 104          */
 105         function isCacheable() {
 106                 return $this->getCacheExpiry() > 0;
 107         }
 108
 109         /**
 110          * Return true if this cached output object predates the global or
 111          * per-article cache invalidation timestamps, or if it comes from
 112          * an incompatible older version.
 113          *
 114          * @param $touched String: the affected article's last touched timestamp
 115          * @return Boolean
 116          */
 117         public function expired( $touched ) {
 118                 global $wgCacheEpoch;
 119                 return !$this->isCacheable() || // parser says it's uncacheable
 120                         $this->getCacheTime() < $touched ||
 121                         $this->getCacheTime() <= $wgCacheEpoch ||
 122                         $this->getCacheTime() < wfTimestamp( TS_MW, time() - $this->getCacheExpiry() ) || // expiry period has passed
 123                         !isset( $this->mVersion ) ||
 124                         version_compare( $this->mVersion, Parser::VERSION, "lt" );
 125         }
 126
 127 }