X-Git-Url: http://git.cyclocoop.org//%22http:/%22.attribut_html%28%24lesurls%5B%24numero%5D%29.%22/%22?a=blobdiff_plain;f=includes%2FBacklinkCache.php;h=2aba29f65bed897b9835d0c998c0cae20e984ec9;hb=250da851d1ab6d01a7c53a6e947b699e54b4b470;hp=cdf82f9022e41203d8e9036aa1cc25eaf34bc437;hpb=a828027890ada986f83b420c41a659100d472331;p=lhc%2Fweb%2Fwiklou.git diff --git a/includes/BacklinkCache.php b/includes/BacklinkCache.php index cdf82f9022..2aba29f65b 100644 --- a/includes/BacklinkCache.php +++ b/includes/BacklinkCache.php @@ -1,30 +1,107 @@ getBacklinkCache(). + * Class for fetching backlink lists, approximate backlink counts and + * partitions. * - * Ideally you should only get your backlinks from here when you think there is some - * advantage in caching them. Otherwise it's just a waste of memory. + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * http://www.gnu.org/copyleft/gpl.html + * + * @file + * @author Tim Starling + * @copyright © 2009, Tim Starling, Domas Mituzas + * @copyright © 2010, Max Sem + * @copyright © 2011, Antoine Musso + */ + +/** + * Class for fetching backlink lists, approximate backlink counts and + * partitions. This is a shared cache. + * + * Instances of this class should typically be fetched with the method + * $title->getBacklinkCache(). + * + * Ideally you should only get your backlinks from here when you think + * there is some advantage in caching them. Otherwise it's just a waste + * of memory. + * + * Introduced by r47317 + * + * @internal documentation reviewed on 18 Mar 2011 by hashar */ class BacklinkCache { - var $partitionCache = array(); - var $fullResultCache = array(); - var $title; - var $db; + + /** + * Multi dimensions array representing batches. Keys are: + * > (string) links table name + * > 'numRows' : Number of rows for this link table + * > 'batches' : array( $start, $end ) + * + * @see BacklinkCache::partitionResult() + * + * Cleared with BacklinkCache::clear() + */ + protected $partitionCache = array(); + + /** + * Contains the whole links from a database result. + * This is raw data that will be partitioned in $partitionCache + * + * Initialized with BacklinkCache::getLinks() + * Cleared with BacklinkCache::clear() + */ + protected $fullResultCache = array(); + + /** + * Local copy of a database object. + * + * Accessor: BacklinkCache::getDB() + * Mutator : BacklinkCache::setDB() + * Cleared with BacklinkCache::clear() + */ + protected $db; + + /** + * Local copy of a Title object + */ + protected $title; const CACHE_EXPIRY = 3600; /** * Create a new BacklinkCache + * @param Title $title : Title object to create a backlink cache for. */ function __construct( $title ) { $this->title = $title; } /** - * Clear locally stored data + * Serialization handler, diasallows to serialize the database to prevent + * failures after this class is deserialized from cache with dead DB + * connection. + * + * @return array */ - function clear() { + function __sleep() { + return array( 'partitionCache', 'fullResultCache', 'title' ); + } + + /** + * Clear locally stored data and database object. + */ + public function clear() { $this->partitionCache = array(); $this->fullResultCache = array(); unset( $this->db ); @@ -32,11 +109,18 @@ class BacklinkCache { /** * Set the Database object to use + * + * @param $db DatabaseBase */ public function setDB( $db ) { $this->db = $db; } + /** + * Get the slave connection to the database + * When non existing, will initialize the connection. + * @return DatabaseBase object + */ protected function getDB() { if ( !isset( $this->db ) ) { $this->db = wfGetDB( DB_SLAVE ); @@ -50,7 +134,7 @@ class BacklinkCache { * @param $table String * @param $startId Integer or false * @param $endId Integer or false - * @return TitleArray + * @return TitleArrayFromResult */ public function getLinks( $table, $startId = false, $endId = false ) { wfProfileIn( __METHOD__ ); @@ -87,6 +171,7 @@ class BacklinkCache { return $ta; } + // @todo FIXME: Make this a function? if ( !isset( $this->fullResultCache[$table] ) ) { wfDebug( __METHOD__ . ": from DB\n" ); $res = $this->getDB()->select( @@ -109,36 +194,59 @@ class BacklinkCache { /** * Get the field name prefix for a given table + * @param $table String + * @return null|string */ protected function getPrefix( $table ) { static $prefixes = array( - 'pagelinks' => 'pl', - 'imagelinks' => 'il', + 'pagelinks' => 'pl', + 'imagelinks' => 'il', 'categorylinks' => 'cl', 'templatelinks' => 'tl', - 'redirect' => 'rd', + 'redirect' => 'rd', ); if ( isset( $prefixes[$table] ) ) { return $prefixes[$table]; } else { - throw new MWException( "Invalid table \"$table\" in " . __CLASS__ ); + $prefix = null; + wfRunHooks( 'BacklinkCacheGetPrefix', array( $table, &$prefix ) ); + if( $prefix ) { + return $prefix; + } else { + throw new MWException( "Invalid table \"$table\" in " . __CLASS__ ); + } } } /** - * Get the SQL condition array for selecting backlinks, with a join on the page table + * Get the SQL condition array for selecting backlinks, with a join + * on the page table. + * @param $table String + * @return array|null */ protected function getConditions( $table ) { $prefix = $this->getPrefix( $table ); + // @todo FIXME: imagelinks and categorylinks do not rely on getNamespace, + // they could be moved up for nicer case statements switch ( $table ) { case 'pagelinks': case 'templatelinks': + $conds = array( + "{$prefix}_namespace" => $this->title->getNamespace(), + "{$prefix}_title" => $this->title->getDBkey(), + "page_id={$prefix}_from" + ); + break; case 'redirect': $conds = array( "{$prefix}_namespace" => $this->title->getNamespace(), - "{$prefix}_title" => $this->title->getDBkey(), + "{$prefix}_title" => $this->title->getDBkey(), + $this->getDb()->makeList( array( + "{$prefix}_interwiki = ''", + "{$prefix}_interwiki is null", + ), LIST_OR ), "page_id={$prefix}_from" ); break; @@ -155,7 +263,10 @@ class BacklinkCache { ); break; default: - throw new MWException( "Invalid table \"$table\" in " . __CLASS__ ); + $conds = null; + wfRunHooks( 'BacklinkCacheGetConditions', array( $table, $this->title, &$conds ) ); + if( !$conds ) + throw new MWException( "Invalid table \"$table\" in " . __CLASS__ ); } return $conds; @@ -163,6 +274,8 @@ class BacklinkCache { /** * Get the approximate number of backlinks + * @param $table String + * @return integer */ public function getNumLinks( $table ) { if ( isset( $this->fullResultCache[$table] ) ) { @@ -181,15 +294,17 @@ class BacklinkCache { /** * Partition the backlinks into batches. - * Returns an array giving the start and end of each range. The first batch has - * a start of false, and the last batch has an end of false. + * Returns an array giving the start and end of each range. The first + * batch has a start of false, and the last batch has an end of false. * * @param $table String: the links table name * @param $batchSize Integer * @return Array */ public function partition( $table, $batchSize ) { - // Try cache + + // 1) try partition cache ... + if ( isset( $this->partitionCache[$table][$batchSize] ) ) { wfDebug( __METHOD__ . ": got from partition cache\n" ); return $this->partitionCache[$table][$batchSize]['batches']; @@ -198,7 +313,8 @@ class BacklinkCache { $this->partitionCache[$table][$batchSize] = false; $cacheEntry =& $this->partitionCache[$table][$batchSize]; - // Try full result cache + // 2) ... then try full result cache ... + if ( isset( $this->fullResultCache[$table] ) ) { $cacheEntry = $this->partitionResult( $this->fullResultCache[$table], $batchSize ); wfDebug( __METHOD__ . ": got from full result cache\n" ); @@ -206,9 +322,9 @@ class BacklinkCache { return $cacheEntry['batches']; } - // Try memcached + // 3) ... fallback to memcached ... + global $wgMemc; - global $wgContLang; $memcKey = wfMemcKey( 'backlinks', @@ -217,9 +333,6 @@ class BacklinkCache { $batchSize ); - if ( $wgContLang === null ) $wgContLang = new Language; - if ( $wgMemc === null ) $wgMemc =& wfGetMainCache(); - $memcValue = $wgMemc->get( $memcKey ); if ( is_array( $memcValue ) ) { @@ -229,7 +342,9 @@ class BacklinkCache { return $cacheEntry['batches']; } - // Fetch from database + + // 4) ... finally fetch from the slow database :( + $this->getLinks( $table ); $cacheEntry = $this->partitionResult( $this->fullResultCache[$table], $batchSize ); // Save to memcached @@ -241,6 +356,9 @@ class BacklinkCache { /** * Partition a DB result with backlinks in it into batches + * @param $res ResultWrapper database result + * @param $batchSize integer + * @return array @see */ protected function partitionResult( $res, $batchSize ) { $batches = array();