summaryrefslogtreecommitdiff
path: root/includes/cache/LinkCache.php
blob: 0e41e265b1284b85a5b089ac8034f90ee2cb7474 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
<?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 {
	// Increment $mClassVer whenever old serialized versions of this class
	// becomes incompatible with the new version.
	private $mClassVer = 4;

	private $mGoodLinks = array();
	private $mGoodLinkFields = array();
	private $mBadLinks = array();
	private $mForUpdate = false;

	/**
	 * Get an instance of this class
	 *
	 * @return LinkCache
	 */
	static function &singleton() {
		static $instance;
		if ( !isset( $instance ) ) {
			$instance = new LinkCache;
		}
		return $instance;
	}

	/**
	 * General accessor to get/set whether SELECT FOR UPDATE should be used
	 *
	 * @return bool
	 */
	public function forUpdate( $update = null ) {
		return wfSetVar( $this->mForUpdate, $update );
	}

	/**
	 * @param $title
	 * @return array|int
	 */
	public function getGoodLinkID( $title ) {
		if ( array_key_exists( $title, $this->mGoodLinks ) ) {
			return $this->mGoodLinks[$title];
		} else {
			return 0;
		}
	}

	/**
	 * Get a field of a title object from cache.
	 * If this link is not good, it will return NULL.
	 * @param $title Title
	 * @param string $field ('length','redirect','revision','model')
	 * @return mixed
	 */
	public function getGoodLinkFieldObj( $title, $field ) {
		$dbkey = $title->getPrefixedDBkey();
		if ( array_key_exists( $dbkey, $this->mGoodLinkFields ) ) {
			return $this->mGoodLinkFields[$dbkey][$field];
		} else {
			return null;
		}
	}

	/**
	 * @param $title
	 * @return bool
	 */
	public function isBadLink( $title ) {
		return array_key_exists( $title, $this->mBadLinks );
	}

	/**
	 * Add a link for the title to the link cache
	 *
	 * @param $id Integer: page's ID
	 * @param $title Title object
	 * @param $len Integer: text's length
	 * @param $redir Integer: whether the page is a redirect
	 * @param $revision Integer: latest revision's ID
	 * @param $model Integer: latest revision's content model ID
	 */
	public function addGoodLinkObj( $id, $title, $len = -1, $redir = null, $revision = false, $model = false ) {
		$dbkey = $title->getPrefixedDBkey();
		$this->mGoodLinks[$dbkey] = intval( $id );
		$this->mGoodLinkFields[$dbkey] = array(
			'length' => intval( $len ),
			'redirect' => intval( $redir ),
			'revision' => intval( $revision ),
			'model' => intval( $model ) );
	}

	/**
	 * Same as above with better interface.
	 * @since 1.19
	 * @param $title Title
	 * @param $row object which has the fields page_id, page_is_redirect,
	 *  page_latest and page_content_model
	 */
	public function addGoodLinkObjFromRow( $title, $row ) {
		$dbkey = $title->getPrefixedDBkey();
		$this->mGoodLinks[$dbkey] = intval( $row->page_id );
		$this->mGoodLinkFields[$dbkey] = array(
			'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 ) {
		$dbkey = $title->getPrefixedDBkey();
		if ( !$this->isBadLink( $dbkey ) ) {
			$this->mBadLinks[$dbkey] = 1;
		}
	}

	public function clearBadLink( $title ) {
		unset( $this->mBadLinks[$title] );
	}

	/**
	 * @param $title Title
	 */
	public function clearLink( $title ) {
		$dbkey = $title->getPrefixedDBkey();
		unset( $this->mBadLinks[$dbkey] );
		unset( $this->mGoodLinks[$dbkey] );
		unset( $this->mGoodLinkFields[$dbkey] );
	}

	public function getGoodLinks() { return $this->mGoodLinks; }
	public function getBadLinks() { return array_keys( $this->mBadLinks ); }

	/**
	 * Add a title to the link cache, return the page_id or zero if non-existent
	 *
	 * @param string $title title to add
	 * @return Integer
	 */
	public function addLink( $title ) {
		$nt = Title::newFromDBkey( $title );
		if( $nt ) {
			return $this->addLinkObj( $nt );
		} else {
			return 0;
		}
	}

	/**
	 * Add a title to the link cache, return the page_id or zero if non-existent
	 *
	 * @param $nt Title object to add
	 * @return Integer
	 */
	public function addLinkObj( $nt ) {
		global $wgAntiLockFlags, $wgContentHandlerUseDB;

		wfProfileIn( __METHOD__ );

		$key = $nt->getPrefixedDBkey();
		if ( $this->isBadLink( $key ) || $nt->isExternal() ) {
			wfProfileOut( __METHOD__ );
			return 0;
		}
		$id = $this->getGoodLinkID( $key );
		if ( $id != 0 ) {
			wfProfileOut( __METHOD__ );
			return $id;
		}

		if ( $key === '' ) {
			wfProfileOut( __METHOD__ );
			return 0;
		}

		# Some fields heavily used for linking...
		if ( $this->mForUpdate ) {
			$db = wfGetDB( DB_MASTER );
			if ( !( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) ) {
				$options = array( 'FOR UPDATE' );
			} else {
				$options = array();
			}
		} else {
			$db = wfGetDB( DB_SLAVE );
			$options = array();
		}

		$f = array( 'page_id', 'page_len', 'page_is_redirect', 'page_latest' );
		if ( $wgContentHandlerUseDB ) $f[] = 'page_content_model';

		$s = $db->selectRow( 'page', $f,
			array( 'page_namespace' => $nt->getNamespace(), 'page_title' => $nt->getDBkey() ),
			__METHOD__, $options );
		# Set fields...
		if ( $s !== false ) {
			$this->addGoodLinkObjFromRow( $nt, $s );
			$id = intval( $s->page_id );
		} else {
			$this->addBadLinkObj( $nt );
			$id = 0;
		}

		wfProfileOut( __METHOD__ );
		return $id;
	}

	/**
	 * Clears cache
	 */
	public function clear() {
		$this->mGoodLinks = array();
		$this->mGoodLinkFields = array();
		$this->mBadLinks = array();
	}
}