3 * Page existence cache.
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.
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.
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
24 use Wikimedia\Rdbms\Database
;
25 use Wikimedia\Rdbms\IDatabase
;
26 use MediaWiki\Linker\LinkTarget
;
27 use MediaWiki\MediaWikiServices
;
30 * Cache for article titles (prefixed DB keys) and ids linked from one source
35 /** @var MapCacheLRU */
37 /** @var MapCacheLRU */
39 /** @var WANObjectCache */
43 private $mForUpdate = false;
45 /** @var TitleFormatter */
46 private $titleFormatter;
48 /** @var NamespaceInfo */
52 * How many Titles to store. There are two caches, so the amount actually
53 * stored in memory can be up to twice this.
55 const MAX_SIZE
= 10000;
57 public function __construct(
58 TitleFormatter
$titleFormatter,
59 WANObjectCache
$cache,
60 NamespaceInfo
$nsInfo = null
63 wfDeprecated( __METHOD__
. ' with no NamespaceInfo argument', '1.34' );
64 $nsInfo = MediaWikiServices
::getInstance()->getNamespaceInfo();
66 $this->goodLinks
= new MapCacheLRU( self
::MAX_SIZE
);
67 $this->badLinks
= new MapCacheLRU( self
::MAX_SIZE
);
68 $this->wanCache
= $cache;
69 $this->titleFormatter
= $titleFormatter;
70 $this->nsInfo
= $nsInfo;
74 * Get an instance of this class.
77 * @deprecated since 1.28, use MediaWikiServices instead
79 public static function singleton() {
80 return MediaWikiServices
::getInstance()->getLinkCache();
84 * General accessor to get/set whether the master DB should be used
86 * This used to also set the FOR UPDATE option (locking the rows read
87 * in order to avoid link table inconsistency), which was later removed
88 * for performance on wikis with a high edit rate.
90 * @param bool|null $update
93 public function forUpdate( $update = null ) {
94 return wfSetVar( $this->mForUpdate
, $update );
98 * @param string $title Prefixed DB key
99 * @return int Page ID or zero
101 public function getGoodLinkID( $title ) {
102 $info = $this->goodLinks
->get( $title );
110 * Get a field of a title object from cache.
111 * If this link is not a cached good title, it will return NULL.
112 * @param LinkTarget $target
113 * @param string $field ('length','redirect','revision','model')
114 * @return string|int|null
116 public function getGoodLinkFieldObj( LinkTarget
$target, $field ) {
117 $dbkey = $this->titleFormatter
->getPrefixedDBkey( $target );
118 $info = $this->goodLinks
->get( $dbkey );
122 return $info[$field];
126 * @param string $title Prefixed DB key
129 public function isBadLink( $title ) {
130 // Use get() to ensure it records as used for LRU.
131 return $this->badLinks
->has( $title );
135 * Add a link for the title to the link cache
137 * @param int $id Page's ID
138 * @param LinkTarget $target
139 * @param int $len Text's length
140 * @param int|null $redir Whether the page is a redirect
141 * @param int $revision Latest revision's ID
142 * @param string|null $model Latest revision's content model ID
143 * @param string|null $lang Language code of the page, if not the content language
145 public function addGoodLinkObj( $id, LinkTarget
$target, $len = -1, $redir = null,
146 $revision = 0, $model = null, $lang = null
148 $dbkey = $this->titleFormatter
->getPrefixedDBkey( $target );
149 $this->goodLinks
->set( $dbkey, [
151 'length' => (int)$len,
152 'redirect' => (int)$redir,
153 'revision' => (int)$revision,
154 'model' => $model ?
(string)$model : null,
155 'lang' => $lang ?
(string)$lang : null,
156 'restrictions' => null
161 * Same as above with better interface.
163 * @param LinkTarget $target
164 * @param stdClass $row Object which has the fields page_id, page_is_redirect,
165 * page_latest and page_content_model
167 public function addGoodLinkObjFromRow( LinkTarget
$target, $row ) {
168 $dbkey = $this->titleFormatter
->getPrefixedDBkey( $target );
169 $this->goodLinks
->set( $dbkey, [
170 'id' => intval( $row->page_id
),
171 'length' => intval( $row->page_len
),
172 'redirect' => intval( $row->page_is_redirect
),
173 'revision' => intval( $row->page_latest
),
174 'model' => !empty( $row->page_content_model
)
175 ?
strval( $row->page_content_model
)
177 'lang' => !empty( $row->page_lang
)
178 ?
strval( $row->page_lang
)
180 'restrictions' => !empty( $row->page_restrictions
)
181 ?
strval( $row->page_restrictions
)
187 * @param LinkTarget $target
189 public function addBadLinkObj( LinkTarget
$target ) {
190 $dbkey = $this->titleFormatter
->getPrefixedDBkey( $target );
191 if ( !$this->isBadLink( $dbkey ) ) {
192 $this->badLinks
->set( $dbkey, 1 );
197 * @param string $title Prefixed DB key
199 public function clearBadLink( $title ) {
200 $this->badLinks
->clear( $title );
204 * @param LinkTarget $target
206 public function clearLink( LinkTarget
$target ) {
207 $dbkey = $this->titleFormatter
->getPrefixedDBkey( $target );
208 $this->badLinks
->clear( $dbkey );
209 $this->goodLinks
->clear( $dbkey );
213 * Fields that LinkCache needs to select
218 public static function getSelectFields() {
219 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
228 if ( $wgContentHandlerUseDB ) {
229 $fields[] = 'page_content_model';
231 if ( $wgPageLanguageUseDB ) {
232 $fields[] = 'page_lang';
239 * Add a title to the link cache, return the page_id or zero if non-existent
241 * @param LinkTarget $nt LinkTarget object to add
242 * @return int Page ID or zero
244 public function addLinkObj( LinkTarget
$nt ) {
245 $key = $this->titleFormatter
->getPrefixedDBkey( $nt );
246 if ( $this->isBadLink( $key ) ||
$nt->isExternal()
247 ||
$nt->inNamespace( NS_SPECIAL
)
251 $id = $this->getGoodLinkID( $key );
260 // Cache template/file pages as they are less often viewed but heavily used
261 if ( $this->mForUpdate
) {
262 $row = $this->fetchPageRow( wfGetDB( DB_MASTER
), $nt );
263 } elseif ( $this->isCacheable( $nt ) ) {
264 // These pages are often transcluded heavily, so cache them
265 $cache = $this->wanCache
;
266 $row = $cache->getWithSetCallback(
267 $cache->makeKey( 'page', $nt->getNamespace(), sha1( $nt->getDBkey() ) ),
269 function ( $curValue, &$ttl, array &$setOpts ) use ( $cache, $nt ) {
270 $dbr = wfGetDB( DB_REPLICA
);
271 $setOpts +
= Database
::getCacheSetOptions( $dbr );
273 $row = $this->fetchPageRow( $dbr, $nt );
274 $mtime = $row ?
wfTimestamp( TS_UNIX
, $row->page_touched
) : false;
275 $ttl = $cache->adaptiveTTL( $mtime, $ttl );
281 $row = $this->fetchPageRow( wfGetDB( DB_REPLICA
), $nt );
285 $this->addGoodLinkObjFromRow( $nt, $row );
286 $id = intval( $row->page_id
);
288 $this->addBadLinkObj( $nt );
296 * @param WANObjectCache $cache
297 * @param LinkTarget $t
301 public function getMutableCacheKeys( WANObjectCache
$cache, LinkTarget
$t ) {
302 if ( $this->isCacheable( $t ) ) {
303 return [ $cache->makeKey( 'page', $t->getNamespace(), sha1( $t->getDBkey() ) ) ];
309 private function isCacheable( LinkTarget
$title ) {
310 $ns = $title->getNamespace();
311 if ( in_array( $ns, [ NS_TEMPLATE
, NS_FILE
, NS_CATEGORY
] ) ) {
314 // Focus on transcluded pages more than the main content
315 if ( $this->nsInfo
->isContent( $ns ) ) {
318 // Non-talk extension namespaces (e.g. NS_MODULE)
319 return ( $ns >= 100 && $this->nsInfo
->isSubject( $ns ) );
322 private function fetchPageRow( IDatabase
$db, LinkTarget
$nt ) {
323 $fields = self
::getSelectFields();
324 if ( $this->isCacheable( $nt ) ) {
325 $fields[] = 'page_touched';
328 return $db->selectRow(
331 [ 'page_namespace' => $nt->getNamespace(), 'page_title' => $nt->getDBkey() ],
337 * Purge the link cache for a title
339 * @param LinkTarget $title
342 public function invalidateTitle( LinkTarget
$title ) {
343 if ( $this->isCacheable( $title ) ) {
344 $cache = $this->wanCache
;
346 $cache->makeKey( 'page', $title->getNamespace(), sha1( $title->getDBkey() ) )
354 public function clear() {
355 $this->goodLinks
->clear();
356 $this->badLinks
->clear();