summaryrefslogtreecommitdiff
path: root/includes/LinkBatch.php
blob: bdc4b43a3db0369e2c28a2768473656ea7682863 (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
<?php

/**
 * Class representing a list of titles
 * The execute() method checks them all for existence and adds them to a LinkCache object
 *
 * @ingroup Cache
 */
class LinkBatch {
	/**
	 * 2-d array, first index namespace, second index dbkey, value arbitrary
	 */
	var $data = array();

	function __construct( $arr = array() ) {
		foreach( $arr as $item ) {
			$this->addObj( $item );
		}
	}

	public function addObj( $title ) {
		if ( is_object( $title ) ) {
			$this->add( $title->getNamespace(), $title->getDBkey() );
		} else {
			wfDebug( "Warning: LinkBatch::addObj got invalid title object\n" );
		}
	}

	public function add( $ns, $dbkey ) {
		if ( $ns < 0 ) {
			return;
		}
		if ( !array_key_exists( $ns, $this->data ) ) {
			$this->data[$ns] = array();
		}

		$this->data[$ns][str_replace( ' ', '_', $dbkey )] = 1;
	}

	/**
	 * Set the link list to a given 2-d array
	 * First key is the namespace, second is the DB key, value arbitrary
	 */
	public function setArray( $array ) {
		$this->data = $array;
	}

	/**
	 * Returns true if no pages have been added, false otherwise.
	 */
	public function isEmpty() {
		return ($this->getSize() == 0);
	}

	/**
	 * Returns the size of the batch.
	 */
	public function getSize() {
		return count( $this->data );
	}

	/**
	 * Do the query and add the results to the LinkCache object
	 * Return an array mapping PDBK to ID
	 */
	 public function execute() {
	 	$linkCache = LinkCache::singleton();
	 	return $this->executeInto( $linkCache );
	 }

	/**
	 * Do the query and add the results to a given LinkCache object
	 * Return an array mapping PDBK to ID
	 */
	protected function executeInto( &$cache ) {
		wfProfileIn( __METHOD__ );
		$res = $this->doQuery();
		$ids = $this->addResultToCache( $cache, $res );
		wfProfileOut( __METHOD__ );
		return $ids;
	}

	/**
	 * Add a ResultWrapper containing IDs and titles to a LinkCache object.
	 * As normal, titles will go into the static Title cache field.
	 * This function *also* stores extra fields of the title used for link
	 * parsing to avoid extra DB queries.
	 */
	public function addResultToCache( $cache, $res ) {
		if ( !$res ) {
			return array();
		}

		// For each returned entry, add it to the list of good links, and remove it from $remaining

		$ids = array();
		$remaining = $this->data;
		while ( $row = $res->fetchObject() ) {
			$title = Title::makeTitle( $row->page_namespace, $row->page_title );
			$cache->addGoodLinkObj( $row->page_id, $title, $row->page_len, $row->page_is_redirect );
			$ids[$title->getPrefixedDBkey()] = $row->page_id;
			unset( $remaining[$row->page_namespace][$row->page_title] );
		}

		// The remaining links in $data are bad links, register them as such
		foreach ( $remaining as $ns => $dbkeys ) {
			foreach ( $dbkeys as $dbkey => $unused ) {
				$title = Title::makeTitle( $ns, $dbkey );
				$cache->addBadLinkObj( $title );
				$ids[$title->getPrefixedDBkey()] = 0;
			}
		}
		return $ids;
	}

	/**
	 * Perform the existence test query, return a ResultWrapper with page_id fields
	 */
	public function doQuery() {
		if ( $this->isEmpty() ) {
			return false;
		}
		wfProfileIn( __METHOD__ );

		// Construct query
		// This is very similar to Parser::replaceLinkHolders
		$dbr = wfGetDB( DB_SLAVE );
		$page = $dbr->tableName( 'page' );
		$set = $this->constructSet( 'page', $dbr );
		if ( $set === false ) {
			wfProfileOut( __METHOD__ );
			return false;
		}
		$sql = "SELECT page_id, page_namespace, page_title, page_len, page_is_redirect FROM $page WHERE $set";

		// Do query
		$res = new ResultWrapper( $dbr,  $dbr->query( $sql, __METHOD__ ) );
		wfProfileOut( __METHOD__ );
		return $res;
	}

	/**
	 * Construct a WHERE clause which will match all the given titles.
	 *
	 * @param string $prefix the appropriate table's field name prefix ('page', 'pl', etc)
	 * @return string
	 * @public
	 */
	public function constructSet( $prefix, &$db ) {
		$first = true;
		$firstTitle = true;
		$sql = '';
		foreach ( $this->data as $ns => $dbkeys ) {
			if ( !count( $dbkeys ) ) {
				continue;
			}

			if ( $first ) {
				$first = false;
			} else {
				$sql .= ' OR ';
			}

			if (count($dbkeys)==1) { // avoid multiple-reference syntax if simple equality can be used
				$singleKey = array_keys($dbkeys);
				$sql .= "({$prefix}_namespace=$ns AND {$prefix}_title=".
					$db->addQuotes($singleKey[0]).
					")";
			} else {
				$sql .= "({$prefix}_namespace=$ns AND {$prefix}_title IN (";

				$firstTitle = true;
				foreach( $dbkeys as $dbkey => $unused ) {
					if ( $firstTitle ) {
						$firstTitle = false;
					} else {
						$sql .= ',';
					}
					$sql .= $db->addQuotes( $dbkey );
				}
				$sql .= '))';
			}
		}
		if ( $first && $firstTitle ) {
			# No titles added
			return false;
		} else {
			return $sql;
		}
	}
}