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         /** @var string Compatibility check */
  36         protected $mVersion = Parser::VERSION;
  37
  38         /** @var string Time when this object was generated, or -1 for uncacheable. Used in ParserCache. */
  39         protected $mCacheTime = '';
  40
  41         /**
  42          * @var int Seconds after which the object should expire, use 0 for uncachable.
  43          *   Used in ParserCache.
  44          */
  45         protected $mCacheExpiry = null;
  46
  47         /** @var bool Boolean variable indicating if the input contained variables like {{CURRENTDAY}} */
  48         protected $mContainsOldMagic;
  49
  50         /** @var int Revision ID that was parsed */
  51         protected $mCacheRevisionId = null;
  52
  53         /**
  54          * @return string TS_MW timestamp
  55          */
  56         function getCacheTime() {
  57                 return wfTimestamp( TS_MW, $this->mCacheTime );
  58         }
  59
  60         /**
  61          * @return bool
  62          */
  63         function containsOldMagic() {
  64                 return $this->mContainsOldMagic;
  65         }
  66
  67         /**
  68          * @param bool $com
  69          * @return bool
  70          */
  71         function setContainsOldMagic( $com ) {
  72                 return wfSetVar( $this->mContainsOldMagic, $com );
  73         }
  74
  75         /**
  76          * setCacheTime() sets the timestamp expressing when the page has been rendered.
  77          * This does not control expiry, see updateCacheExpiry() for that!
  78          * @param string $t
  79          * @return string
  80          */
  81         function setCacheTime( $t ) {
  82                 return wfSetVar( $this->mCacheTime, $t );
  83         }
  84
  85         /**
  86          * @since 1.23
  87          * @return int|null Revision id, if any was set
  88          */
  89         function getCacheRevisionId() {
  90                 return $this->mCacheRevisionId;
  91         }
  92
  93         /**
  94          * @since 1.23
  95          * @param int $id Revision id
  96          */
  97         function setCacheRevisionId( $id ) {
  98                 $this->mCacheRevisionId = $id;
  99         }
 100
 101         /**
 102          * Sets the number of seconds after which this object should expire.
 103          * This value is used with the ParserCache.
 104          * If called with a value greater than the value provided at any previous call,
 105          * the new call has no effect. The value returned by getCacheExpiry is smaller
 106          * or equal to the smallest number that was provided as an argument to
 107          * updateCacheExpiry().
 108          *
 109          * @param int $seconds
 110          */
 111         function updateCacheExpiry( $seconds ) {
 112                 $seconds = (int)$seconds;
 113
 114                 if ( $this->mCacheExpiry === null || $this->mCacheExpiry > $seconds ) {
 115                         $this->mCacheExpiry = $seconds;
 116                 }
 117
 118                 // hack: set old-style marker for uncacheable entries.
 119                 if ( $this->mCacheExpiry !== null && $this->mCacheExpiry <= 0 ) {
 120                         $this->mCacheTime = -1;
 121                 }
 122         }
 123
 124         /**
 125          * Returns the number of seconds after which this object should expire.
 126          * This method is used by ParserCache to determine how long the ParserOutput can be cached.
 127          * The timestamp of expiry can be calculated by adding getCacheExpiry() to getCacheTime().
 128          * The value returned by getCacheExpiry is smaller or equal to the smallest number
 129          * that was provided to a call of updateCacheExpiry(), and smaller or equal to the
 130          * value of $wgParserCacheExpireTime.
 131          * @return int|mixed|null
 132          */
 133         function getCacheExpiry() {
 134                 global $wgParserCacheExpireTime;
 135
 136                 if ( $this->mCacheTime < 0 ) {
 137                         return 0;
 138                 } // old-style marker for "not cachable"
 139
 140                 $expire = $this->mCacheExpiry;
 141
 142                 if ( $expire === null ) {
 143                         $expire = $wgParserCacheExpireTime;
 144                 } else {
 145                         $expire = min( $expire, $wgParserCacheExpireTime );
 146                 }
 147
 148                 if ( $this->containsOldMagic() ) { //compatibility hack
 149                         $expire = min( $expire, 3600 ); # 1 hour
 150                 }
 151
 152                 if ( $expire <= 0 ) {
 153                         return 0; // not cachable
 154                 } else {
 155                         return $expire;
 156                 }
 157         }
 158
 159         /**
 160          * @return bool
 161          */
 162         function isCacheable() {
 163                 return $this->getCacheExpiry() > 0;
 164         }
 165
 166         /**
 167          * Return true if this cached output object predates the global or
 168          * per-article cache invalidation timestamps, or if it comes from
 169          * an incompatible older version.
 170          *
 171          * @param string $touched The affected article's last touched timestamp
 172          * @return bool
 173          */
 174         public function expired( $touched ) {
 175                 global $wgCacheEpoch;
 176
 177                 return !$this->isCacheable() // parser says it's uncacheable
 178                         || $this->getCacheTime() < $touched
 179                         || $this->getCacheTime() <= $wgCacheEpoch
 180                         || $this->getCacheTime() <
 181                                 wfTimestamp( TS_MW, time() - $this->getCacheExpiry() ) // expiry period has passed
 182                         || !isset( $this->mVersion )
 183                         || version_compare( $this->mVersion, Parser::VERSION, "lt" );
 184         }
 185
 186         /**
 187          * Return true if this cached output object is for a different revision of
 188          * the page.
 189          *
 190          * @todo We always return false if $this->getCacheRevisionId() is null;
 191          * this prevents invalidating the whole parser cache when this change is
 192          * deployed. Someday that should probably be changed.
 193          *
 194          * @since 1.23
 195          * @param int $id The affected article's current revision id
 196          * @return bool
 197          */
 198         public function isDifferentRevision( $id ) {
 199                 $cached = $this->getCacheRevisionId();
 200                 return $cached !== null && $id !== $cached;
 201         }
 202 }