mirror of
https://github.com/YunoHost-Apps/mediawiki_ynh.git
synced 2024-09-03 19:46:05 +02:00
468 lines
13 KiB
PHP
468 lines
13 KiB
PHP
<?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
|
|
* @author Aaron Schulz
|
|
* @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( $dbKey, 'obj', 3600 ) ) {
|
|
self::$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|false
|
|
* @param $endId Integer|false
|
|
* @param $max Integer|INF
|
|
* @return TitleArrayFromResult
|
|
*/
|
|
public function getLinks( $table, $startId = false, $endId = false, $max = INF ) {
|
|
return TitleArray::newFromResult( $this->queryLinks( $table, $startId, $endId, $max ) );
|
|
}
|
|
|
|
/**
|
|
* Get the backlinks for a given table. Cached in process memory only.
|
|
* @param $table String
|
|
* @param $startId Integer|false
|
|
* @param $endId Integer|false
|
|
* @param $max Integer|INF
|
|
* @return ResultWrapper
|
|
*/
|
|
protected function queryLinks( $table, $startId, $endId, $max ) {
|
|
wfProfileIn( __METHOD__ );
|
|
|
|
$fromField = $this->getPrefix( $table ) . '_from';
|
|
|
|
if ( !$startId && !$endId && is_infinite( $max )
|
|
&& isset( $this->fullResultCache[$table] ) )
|
|
{
|
|
wfDebug( __METHOD__ . ": got results from cache\n" );
|
|
$res = $this->fullResultCache[$table];
|
|
} else {
|
|
wfDebug( __METHOD__ . ": got results from DB\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 );
|
|
}
|
|
$options = array( 'STRAIGHT_JOIN', 'ORDER BY' => $fromField );
|
|
if ( is_finite( $max ) && $max > 0 ) {
|
|
$options['LIMIT'] = $max;
|
|
}
|
|
|
|
$res = $this->getDB()->select(
|
|
array( $table, 'page' ),
|
|
array( 'page_namespace', 'page_title', 'page_id' ),
|
|
$conds,
|
|
__METHOD__,
|
|
$options
|
|
);
|
|
|
|
if ( !$startId && !$endId && $res->numRows() < $max ) {
|
|
// The full results fit within the limit, so cache them
|
|
$this->fullResultCache[$table] = $res;
|
|
} else {
|
|
wfDebug( __METHOD__ . ": results from DB were uncacheable\n" );
|
|
}
|
|
}
|
|
|
|
wfProfileOut( __METHOD__ );
|
|
return $res;
|
|
}
|
|
|
|
/**
|
|
* Get the field name prefix for a given table
|
|
* @param $table String
|
|
* @throws MWException
|
|
* @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
|
|
* @throws MWException
|
|
* @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;
|
|
}
|
|
|
|
/**
|
|
* Check if there are any backlinks
|
|
* @param $table String
|
|
* @return bool
|
|
*/
|
|
public function hasLinks( $table ) {
|
|
return ( $this->getNumLinks( $table, 1 ) > 0 );
|
|
}
|
|
|
|
/**
|
|
* Get the approximate number of backlinks
|
|
* @param $table String
|
|
* @param $max integer|INF Only count up to this many backlinks
|
|
* @return integer
|
|
*/
|
|
public function getNumLinks( $table, $max = INF ) {
|
|
global $wgMemc;
|
|
|
|
// 1) try partition cache ...
|
|
if ( isset( $this->partitionCache[$table] ) ) {
|
|
$entry = reset( $this->partitionCache[$table] );
|
|
return min( $max, $entry['numRows'] );
|
|
}
|
|
|
|
// 2) ... then try full result cache ...
|
|
if ( isset( $this->fullResultCache[$table] ) ) {
|
|
return min( $max, $this->fullResultCache[$table]->numRows() );
|
|
}
|
|
|
|
$memcKey = wfMemcKey( 'numbacklinks', md5( $this->title->getPrefixedDBkey() ), $table );
|
|
|
|
// 3) ... fallback to memcached ...
|
|
$count = $wgMemc->get( $memcKey );
|
|
if ( $count ) {
|
|
return min( $max, $count );
|
|
}
|
|
|
|
// 4) fetch from the database ...
|
|
$count = $this->getLinks( $table, false, false, $max )->count();
|
|
if ( $count < $max ) { // full count
|
|
$wgMemc->set( $memcKey, $count, self::CACHE_EXPIRY );
|
|
}
|
|
|
|
return min( $max, $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 string $table the links table name
|
|
* @param $batchSize Integer
|
|
* @return Array
|
|
*/
|
|
public function partition( $table, $batchSize ) {
|
|
global $wgMemc;
|
|
|
|
// 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'];
|
|
}
|
|
|
|
$memcKey = wfMemcKey(
|
|
'backlinks',
|
|
md5( $this->title->getPrefixedDBkey() ),
|
|
$table,
|
|
$batchSize
|
|
);
|
|
|
|
// 3) ... fallback to memcached ...
|
|
$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 :(
|
|
$cacheEntry = array( 'numRows' => 0, 'batches' => array() ); // final result
|
|
// Do the selects in batches to avoid client-side OOMs (bug 43452).
|
|
// Use a LIMIT that plays well with $batchSize to keep equal sized partitions.
|
|
$selectSize = max( $batchSize, 200000 - ( 200000 % $batchSize ) );
|
|
$start = false;
|
|
do {
|
|
$res = $this->queryLinks( $table, $start, false, $selectSize );
|
|
$partitions = $this->partitionResult( $res, $batchSize, false );
|
|
// Merge the link count and range partitions for this chunk
|
|
$cacheEntry['numRows'] += $partitions['numRows'];
|
|
$cacheEntry['batches'] = array_merge( $cacheEntry['batches'], $partitions['batches'] );
|
|
if ( count( $partitions['batches'] ) ) {
|
|
list( $lStart, $lEnd ) = end( $partitions['batches'] );
|
|
$start = $lEnd + 1; // pick up after this inclusive range
|
|
}
|
|
} while ( $partitions['numRows'] >= $selectSize );
|
|
// Make sure the first range has start=false and the last one has end=false
|
|
if ( count( $cacheEntry['batches'] ) ) {
|
|
$cacheEntry['batches'][0][0] = false;
|
|
$cacheEntry['batches'][count( $cacheEntry['batches'] ) - 1][1] = false;
|
|
}
|
|
|
|
// Save partitions to memcached
|
|
$wgMemc->set( $memcKey, $cacheEntry, self::CACHE_EXPIRY );
|
|
|
|
// Save backlink count to memcached
|
|
$memcKey = wfMemcKey( 'numbacklinks', md5( $this->title->getPrefixedDBkey() ), $table );
|
|
$wgMemc->set( $memcKey, $cacheEntry['numRows'], 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
|
|
* @param $isComplete bool Whether $res includes all the backlinks
|
|
* @throws MWException
|
|
* @return array
|
|
*/
|
|
protected function partitionResult( $res, $batchSize, $isComplete = true ) {
|
|
$batches = array();
|
|
$numRows = $res->numRows();
|
|
$numBatches = ceil( $numRows / $batchSize );
|
|
|
|
for ( $i = 0; $i < $numBatches; $i++ ) {
|
|
if ( $i == 0 && $isComplete ) {
|
|
$start = false;
|
|
} else {
|
|
$rowNum = $i * $batchSize;
|
|
$res->seek( $rowNum );
|
|
$row = $res->fetchObject();
|
|
$start = (int)$row->page_id;
|
|
}
|
|
|
|
if ( $i == ( $numBatches - 1 ) && $isComplete ) {
|
|
$end = false;
|
|
} else {
|
|
$rowNum = min( $numRows - 1, ( $i + 1 ) * $batchSize - 1 );
|
|
$res->seek( $rowNum );
|
|
$row = $res->fetchObject();
|
|
$end = (int)$row->page_id;
|
|
}
|
|
|
|
# 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 );
|
|
}
|
|
}
|