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