wiki.techinc.nl/includes/cache/LinkCache.php
Timo Tijhof 03a620004b LinkCache: Convert from MapCacheLRU to HashBagOStuff.
Change-Id: I28a9509ad4c6d724a12dc72bc50d3cf58642c651
2015-11-09 23:17:47 +00:00

275 lines
6.7 KiB
PHP

<?php
/**
* Page existence cache.
*
* 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
* @ingroup Cache
*/
/**
* Cache for article titles (prefixed DB keys) and ids linked from one source
*
* @ingroup Cache
*/
class LinkCache {
/**
* @var HashBagOStuff
*/
private $mGoodLinks;
/**
* @var HashBagOStuff
*/
private $mBadLinks;
private $mForUpdate = false;
/**
* How many Titles to store. There are two caches, so the amount actually
* stored in memory can be up to twice this.
*/
const MAX_SIZE = 10000;
/**
* @var LinkCache
*/
protected static $instance;
public function __construct() {
$this->mGoodLinks = new HashBagOStuff( array( 'maxKeys' => self::MAX_SIZE ) );
$this->mBadLinks = new HashBagOStuff( array( 'maxKeys' => self::MAX_SIZE ) );
}
/**
* Get an instance of this class.
*
* @return LinkCache
*/
public static function &singleton() {
if ( !self::$instance ) {
self::$instance = new LinkCache;
}
return self::$instance;
}
/**
* Destroy the singleton instance
*
* A new one will be created next time singleton() is called.
*
* @since 1.22
*/
public static function destroySingleton() {
self::$instance = null;
}
/**
* Set the singleton instance to a given object.
*
* Since we do not have an interface for LinkCache, you have to be sure the
* given object implements all the LinkCache public methods.
*
* @param LinkCache $instance
* @since 1.22
*/
public static function setSingleton( LinkCache $instance ) {
self::$instance = $instance;
}
/**
* General accessor to get/set whether the master DB should be used
*
* This used to also set the FOR UPDATE option (locking the rows read
* in order to avoid link table inconsistency), which was later removed
* for performance on wikis with a high edit rate.
*
* @param bool $update
* @return bool
*/
public function forUpdate( $update = null ) {
return wfSetVar( $this->mForUpdate, $update );
}
/**
* @param string $title
* @return int Page ID or zero
*/
public function getGoodLinkID( $title ) {
$info = $this->mGoodLinks->get( $title );
if ( !$info ) {
return 0;
}
return $info['id'];
}
/**
* Get a field of a title object from cache.
* If this link is not a cached good title, it will return NULL.
* @param Title $title
* @param string $field ('length','redirect','revision','model')
* @return string|int|null
*/
public function getGoodLinkFieldObj( $title, $field ) {
$dbkey = $title->getPrefixedDBkey();
$info = $this->mGoodLinks->get( $dbkey );
if ( !$info ) {
return null;
}
return $info[$field];
}
/**
* @param string $title
* @return bool
*/
public function isBadLink( $title ) {
// Use get() to ensure it records as used for LRU.
return $this->mBadLinks->get( $title ) !== false;
}
/**
* Add a link for the title to the link cache
*
* @param int $id Page's ID
* @param Title $title
* @param int $len Text's length
* @param int $redir Whether the page is a redirect
* @param int $revision Latest revision's ID
* @param string|null $model Latest revision's content model ID
*/
public function addGoodLinkObj( $id, Title $title, $len = -1, $redir = null,
$revision = 0, $model = null
) {
$dbkey = $title->getPrefixedDBkey();
$this->mGoodLinks->set( $dbkey, array(
'id' => (int)$id,
'length' => (int)$len,
'redirect' => (int)$redir,
'revision' => (int)$revision,
'model' => $model ? (string)$model : null,
) );
}
/**
* Same as above with better interface.
* @since 1.19
* @param Title $title
* @param stdClass $row Object which has the fields page_id, page_is_redirect,
* page_latest and page_content_model
*/
public function addGoodLinkObjFromRow( Title $title, $row ) {
$dbkey = $title->getPrefixedDBkey();
$this->mGoodLinks->set( $dbkey, array(
'id' => intval( $row->page_id ),
'length' => intval( $row->page_len ),
'redirect' => intval( $row->page_is_redirect ),
'revision' => intval( $row->page_latest ),
'model' => !empty( $row->page_content_model ) ? strval( $row->page_content_model ) : null,
) );
}
/**
* @param Title $title
*/
public function addBadLinkObj( Title $title ) {
$dbkey = $title->getPrefixedDBkey();
if ( !$this->isBadLink( $dbkey ) ) {
$this->mBadLinks->set( $dbkey, 1 );
}
}
public function clearBadLink( $title ) {
$this->mBadLinks->clear( array( $title ) );
}
/**
* @param Title $title
*/
public function clearLink( $title ) {
$dbkey = $title->getPrefixedDBkey();
$this->mBadLinks->delete( $dbkey );
$this->mGoodLinks->delete( $dbkey );
}
/**
* Add a title to the link cache, return the page_id or zero if non-existent
*
* @param string $title Title to add
* @return int Page ID or zero
*/
public function addLink( $title ) {
$nt = Title::newFromDBkey( $title );
if ( !$nt ) {
return 0;
}
return $this->addLinkObj( $nt );
}
/**
* Add a title to the link cache, return the page_id or zero if non-existent
*
* @param Title $nt Title object to add
* @return int Page ID or zero
*/
public function addLinkObj( Title $nt ) {
global $wgContentHandlerUseDB;
$key = $nt->getPrefixedDBkey();
if ( $this->isBadLink( $key ) || $nt->isExternal() ) {
return 0;
}
$id = $this->getGoodLinkID( $key );
if ( $id != 0 ) {
return $id;
}
if ( $key === '' ) {
return 0;
}
// Some fields heavily used for linking...
$db = $this->mForUpdate ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
$fields = array( 'page_id', 'page_len', 'page_is_redirect', 'page_latest' );
if ( $wgContentHandlerUseDB ) {
$fields[] = 'page_content_model';
}
$row = $db->selectRow( 'page', $fields,
array( 'page_namespace' => $nt->getNamespace(), 'page_title' => $nt->getDBkey() ),
__METHOD__
);
if ( $row !== false ) {
$this->addGoodLinkObjFromRow( $nt, $row );
$id = intval( $row->page_id );
} else {
$this->addBadLinkObj( $nt );
$id = 0;
}
return $id;
}
/**
* Clears cache
*/
public function clear() {
$this->mGoodLinks->clear();
$this->mBadLinks->clear();
}
}