diff options
author | Pierre Schmitz <pierre@archlinux.de> | 2013-08-12 09:28:15 +0200 |
---|---|---|
committer | Pierre Schmitz <pierre@archlinux.de> | 2013-08-12 09:28:15 +0200 |
commit | 08aa4418c30cfc18ccc69a0f0f9cb9e17be6c196 (patch) | |
tree | 577a29fb579188d16003a209ce2a2e9c5b0aa2bd /includes/BacklinkCache.php | |
parent | cacc939b34e315b85e2d72997811eb6677996cc1 (diff) |
Update to MediaWiki 1.21.1
Diffstat (limited to 'includes/BacklinkCache.php')
-rw-r--r-- | includes/BacklinkCache.php | 419 |
1 files changed, 0 insertions, 419 deletions
diff --git a/includes/BacklinkCache.php b/includes/BacklinkCache.php deleted file mode 100644 index 05bf3186..00000000 --- a/includes/BacklinkCache.php +++ /dev/null @@ -1,419 +0,0 @@ -<?php -/** - * Class for fetching backlink lists, approximate backlink counts and - * partitions. - * - * 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 ProcessCacheLRU */ - protected static $cache; - - /** - * 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 - */ - public function __construct( Title $title ) { - $this->title = $title; - } - - /** - * Create a new BacklinkCache or reuse any existing one. - * Currently, only one cache instance can exist; callers that - * need multiple backlink cache objects should keep them in scope. - * - * @param Title $title : Title object to get a backlink cache for - * @return BacklinkCache - */ - public static function get( Title $title ) { - if ( !self::$cache ) { // init cache - self::$cache = new ProcessCacheLRU( 1 ); - } - $dbKey = $title->getPrefixedDBkey(); - if ( !self::$cache->has( $dbKey, 'obj' ) ) { - self::$cache->set( $dbKey, 'obj', new self( $title ) ); - } - return self::$cache->get( $dbKey, 'obj' ); - } - - /** - * Serialization handler, diasallows to serialize the database to prevent - * failures after this class is deserialized from cache with dead DB - * connection. - * - * @return array - */ - 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 ); - } - - /** - * 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 ); - } - - return $this->db; - } - - /** - * Get the backlinks for a given table. Cached in process memory only. - * @param $table String - * @param $startId Integer or false - * @param $endId Integer or false - * @return TitleArrayFromResult - */ - public function getLinks( $table, $startId = false, $endId = false ) { - wfProfileIn( __METHOD__ ); - - $fromField = $this->getPrefix( $table ) . '_from'; - - if ( $startId || $endId ) { - // Partial range, not cached - wfDebug( __METHOD__ . ": from DB (uncacheable range)\n" ); - $conds = $this->getConditions( $table ); - - // Use the from field in the condition rather than the joined page_id, - // because databases are stupid and don't necessarily propagate indexes. - if ( $startId ) { - $conds[] = "$fromField >= " . intval( $startId ); - } - - if ( $endId ) { - $conds[] = "$fromField <= " . intval( $endId ); - } - - $res = $this->getDB()->select( - array( $table, 'page' ), - array( 'page_namespace', 'page_title', 'page_id' ), - $conds, - __METHOD__, - array( - 'STRAIGHT_JOIN', - 'ORDER BY' => $fromField - ) ); - $ta = TitleArray::newFromResult( $res ); - - wfProfileOut( __METHOD__ ); - return $ta; - } - - // @todo FIXME: Make this a function? - if ( !isset( $this->fullResultCache[$table] ) ) { - wfDebug( __METHOD__ . ": from DB\n" ); - $res = $this->getDB()->select( - array( $table, 'page' ), - array( 'page_namespace', 'page_title', 'page_id' ), - $this->getConditions( $table ), - __METHOD__, - array( - 'STRAIGHT_JOIN', - 'ORDER BY' => $fromField, - ) ); - $this->fullResultCache[$table] = $res; - } - - $ta = TitleArray::newFromResult( $this->fullResultCache[$table] ); - - wfProfileOut( __METHOD__ ); - return $ta; - } - - /** - * 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', - 'categorylinks' => 'cl', - 'templatelinks' => 'tl', - 'redirect' => 'rd', - ); - - if ( isset( $prefixes[$table] ) ) { - return $prefixes[$table]; - } else { - $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. - * @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(), - $this->getDb()->makeList( array( - "{$prefix}_interwiki = ''", - "{$prefix}_interwiki is null", - ), LIST_OR ), - "page_id={$prefix}_from" - ); - break; - case 'imagelinks': - $conds = array( - 'il_to' => $this->title->getDBkey(), - 'page_id=il_from' - ); - break; - case 'categorylinks': - $conds = array( - 'cl_to' => $this->title->getDBkey(), - 'page_id=cl_from', - ); - break; - default: - $conds = null; - wfRunHooks( 'BacklinkCacheGetConditions', array( $table, $this->title, &$conds ) ); - if( !$conds ) - throw new MWException( "Invalid table \"$table\" in " . __CLASS__ ); - } - - return $conds; - } - - /** - * Get the approximate number of backlinks - * @param $table String - * @return integer - */ - public function getNumLinks( $table ) { - if ( isset( $this->fullResultCache[$table] ) ) { - return $this->fullResultCache[$table]->numRows(); - } - - if ( isset( $this->partitionCache[$table] ) ) { - $entry = reset( $this->partitionCache[$table] ); - return $entry['numRows']; - } - - $titleArray = $this->getLinks( $table ); - - return $titleArray->count(); - } - - /** - * 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. - * - * @param $table String: the links table name - * @param $batchSize Integer - * @return Array - */ - public function partition( $table, $batchSize ) { - - // 1) try partition cache ... - - if ( isset( $this->partitionCache[$table][$batchSize] ) ) { - wfDebug( __METHOD__ . ": got from partition cache\n" ); - return $this->partitionCache[$table][$batchSize]['batches']; - } - - $this->partitionCache[$table][$batchSize] = false; - $cacheEntry =& $this->partitionCache[$table][$batchSize]; - - // 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" ); - - return $cacheEntry['batches']; - } - - // 3) ... fallback to memcached ... - - global $wgMemc; - - $memcKey = wfMemcKey( - 'backlinks', - md5( $this->title->getPrefixedDBkey() ), - $table, - $batchSize - ); - - $memcValue = $wgMemc->get( $memcKey ); - - if ( is_array( $memcValue ) ) { - $cacheEntry = $memcValue; - wfDebug( __METHOD__ . ": got from memcached $memcKey\n" ); - - return $cacheEntry['batches']; - } - - - // 4) ... finally fetch from the slow database :( - - $this->getLinks( $table ); - $cacheEntry = $this->partitionResult( $this->fullResultCache[$table], $batchSize ); - // Save to memcached - $wgMemc->set( $memcKey, $cacheEntry, self::CACHE_EXPIRY ); - - wfDebug( __METHOD__ . ": got from database\n" ); - return $cacheEntry['batches']; - } - - /** - * 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(); - $numRows = $res->numRows(); - $numBatches = ceil( $numRows / $batchSize ); - - for ( $i = 0; $i < $numBatches; $i++ ) { - if ( $i == 0 ) { - $start = false; - } else { - $rowNum = intval( $numRows * $i / $numBatches ); - $res->seek( $rowNum ); - $row = $res->fetchObject(); - $start = $row->page_id; - } - - if ( $i == $numBatches - 1 ) { - $end = false; - } else { - $rowNum = intval( $numRows * ( $i + 1 ) / $numBatches ); - $res->seek( $rowNum ); - $row = $res->fetchObject(); - $end = $row->page_id - 1; - } - - # Sanity check order - if ( $start && $end && $start > $end ) { - throw new MWException( __METHOD__ . ': Internal error: query result out of order' ); - } - - $batches[] = array( $start, $end ); - } - - return array( 'numRows' => $numRows, 'batches' => $batches ); - } -} |