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
25 * Cache for article titles (prefixed DB keys) and ids linked from one source
30 // Increment $mClassVer whenever old serialized versions of this class
31 // becomes incompatible with the new version.
32 private $mClassVer = 4;
34 private $mGoodLinks = array();
35 private $mGoodLinkFields = array();
36 private $mBadLinks = array();
37 private $mForUpdate = false;
42 protected static $instance;
45 * Get an instance of this class.
49 static function &singleton() {
50 if ( self
::$instance ) {
51 return self
::$instance;
53 self
::$instance = new LinkCache
;
55 return self
::$instance;
59 * Destroy the singleton instance, a new one will be created next time
60 * singleton() is called.
63 static function destroySingleton() {
64 self
::$instance = null;
68 * Set the singleton instance to a given object.
69 * Since we do not have an interface for LinkCache, you have to be sure the
70 * given object implements all the LinkCache public methods.
71 * @param LinkCache $instance
74 static function setSingleton( LinkCache
$instance ) {
75 self
::$instance = $instance;
79 * General accessor to get/set whether SELECT FOR UPDATE should be used
84 public function forUpdate( $update = null ) {
85 return wfSetVar( $this->mForUpdate
, $update );
89 * @param string $title
92 public function getGoodLinkID( $title ) {
93 if ( array_key_exists( $title, $this->mGoodLinks
) ) {
94 return $this->mGoodLinks
[$title];
101 * Get a field of a title object from cache.
102 * If this link is not good, it will return NULL.
103 * @param Title $title
104 * @param string $field ('length','redirect','revision','model')
105 * @return string|null
107 public function getGoodLinkFieldObj( $title, $field ) {
108 $dbkey = $title->getPrefixedDBkey();
109 if ( array_key_exists( $dbkey, $this->mGoodLinkFields
) ) {
110 return $this->mGoodLinkFields
[$dbkey][$field];
117 * @param string $title
120 public function isBadLink( $title ) {
121 return array_key_exists( $title, $this->mBadLinks
);
125 * Add a link for the title to the link cache
127 * @param int $id Page's ID
128 * @param Title $title
129 * @param int $len Text's length
130 * @param int $redir Whether the page is a redirect
131 * @param int $revision Latest revision's ID
132 * @param string|null $model Latest revision's content model ID
134 public function addGoodLinkObj( $id, $title, $len = -1, $redir = null,
135 $revision = 0, $model = null
137 $dbkey = $title->getPrefixedDBkey();
138 $this->mGoodLinks
[$dbkey] = (int)$id;
139 $this->mGoodLinkFields
[$dbkey] = array(
140 'length' => (int)$len,
141 'redirect' => (int)$redir,
142 'revision' => (int)$revision,
143 'model' => $model ?
(string)$model : null,
148 * Same as above with better interface.
150 * @param Title $title
151 * @param stdClass $row Object which has the fields page_id, page_is_redirect,
152 * page_latest and page_content_model
154 public function addGoodLinkObjFromRow( $title, $row ) {
155 $dbkey = $title->getPrefixedDBkey();
156 $this->mGoodLinks
[$dbkey] = intval( $row->page_id
);
157 $this->mGoodLinkFields
[$dbkey] = array(
158 'length' => intval( $row->page_len
),
159 'redirect' => intval( $row->page_is_redirect
),
160 'revision' => intval( $row->page_latest
),
161 'model' => !empty( $row->page_content_model
) ?
strval( $row->page_content_model
) : null,
166 * @param Title $title
168 public function addBadLinkObj( $title ) {
169 $dbkey = $title->getPrefixedDBkey();
170 if ( !$this->isBadLink( $dbkey ) ) {
171 $this->mBadLinks
[$dbkey] = 1;
175 public function clearBadLink( $title ) {
176 unset( $this->mBadLinks
[$title] );
180 * @param Title $title
182 public function clearLink( $title ) {
183 $dbkey = $title->getPrefixedDBkey();
184 unset( $this->mBadLinks
[$dbkey] );
185 unset( $this->mGoodLinks
[$dbkey] );
186 unset( $this->mGoodLinkFields
[$dbkey] );
189 public function getGoodLinks() {
190 return $this->mGoodLinks
;
193 public function getBadLinks() {
194 return array_keys( $this->mBadLinks
);
198 * Add a title to the link cache, return the page_id or zero if non-existent
200 * @param string $title Title to add
203 public function addLink( $title ) {
204 $nt = Title
::newFromDBkey( $title );
206 return $this->addLinkObj( $nt );
213 * Add a title to the link cache, return the page_id or zero if non-existent
215 * @param Title $nt Title object to add
218 public function addLinkObj( $nt ) {
219 global $wgAntiLockFlags, $wgContentHandlerUseDB;
221 wfProfileIn( __METHOD__
);
223 $key = $nt->getPrefixedDBkey();
224 if ( $this->isBadLink( $key ) ||
$nt->isExternal() ) {
225 wfProfileOut( __METHOD__
);
229 $id = $this->getGoodLinkID( $key );
231 wfProfileOut( __METHOD__
);
237 wfProfileOut( __METHOD__
);
242 # Some fields heavily used for linking...
243 if ( $this->mForUpdate
) {
244 $db = wfGetDB( DB_MASTER
);
245 if ( !( $wgAntiLockFlags & ALF_NO_LINK_LOCK
) ) {
246 $options = array( 'FOR UPDATE' );
251 $db = wfGetDB( DB_SLAVE
);
255 $f = array( 'page_id', 'page_len', 'page_is_redirect', 'page_latest' );
256 if ( $wgContentHandlerUseDB ) {
257 $f[] = 'page_content_model';
260 $s = $db->selectRow( 'page', $f,
261 array( 'page_namespace' => $nt->getNamespace(), 'page_title' => $nt->getDBkey() ),
262 __METHOD__
, $options );
264 if ( $s !== false ) {
265 $this->addGoodLinkObjFromRow( $nt, $s );
266 $id = intval( $s->page_id
);
268 $this->addBadLinkObj( $nt );
272 wfProfileOut( __METHOD__
);
280 public function clear() {
281 $this->mGoodLinks
= array();
282 $this->mGoodLinkFields
= array();
283 $this->mBadLinks
= array();