includes/cache/LinkBatch.php

   1 <?php
   2 /**
   3  * Batch query to determine page existence.
   4  *
   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.
   9  *
  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.
  14  *
  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
  19  *
  20  * @file
  21  * @ingroup Cache
  22  */
  23 use MediaWiki\Linker\LinkTarget;
  24 use MediaWiki\MediaWikiServices;
  25
  26 /**
  27  * Class representing a list of titles
  28  * The execute() method checks them all for existence and adds them to a LinkCache object
  29  *
  30  * @ingroup Cache
  31  */
  32 class LinkBatch {
  33         /**
  34          * 2-d array, first index namespace, second index dbkey, value arbitrary
  35          */
  36         public $data = [];
  37
  38         /**
  39          * For debugging which method is using this class.
  40          */
  41         protected $caller;
  42
  43         function __construct( $arr = [] ) {
  44                 foreach ( $arr as $item ) {
  45                         $this->addObj( $item );
  46                 }
  47         }
  48
  49         /**
  50          * Use ->setCaller( __METHOD__ ) to indicate which code is using this
  51          * class. Only used in debugging output.
  52          * @since 1.17
  53          *
  54          * @param string $caller
  55          */
  56         public function setCaller( $caller ) {
  57                 $this->caller = $caller;
  58         }
  59
  60         /**
  61          * @param LinkTarget $linkTarget
  62          */
  63         public function addObj( $linkTarget ) {
  64                 if ( is_object( $linkTarget ) ) {
  65                         $this->add( $linkTarget->getNamespace(), $linkTarget->getDBkey() );
  66                 } else {
  67                         wfDebug( "Warning: LinkBatch::addObj got invalid LinkTarget object\n" );
  68                 }
  69         }
  70
  71         /**
  72          * @param int $ns
  73          * @param string $dbkey
  74          */
  75         public function add( $ns, $dbkey ) {
  76                 if ( $ns < 0 || $dbkey === '' ) {
  77                         return; // T137083
  78                 }
  79                 if ( !array_key_exists( $ns, $this->data ) ) {
  80                         $this->data[$ns] = [];
  81                 }
  82
  83                 $this->data[$ns][strtr( $dbkey, ' ', '_' )] = 1;
  84         }
  85
  86         /**
  87          * Set the link list to a given 2-d array
  88          * First key is the namespace, second is the DB key, value arbitrary
  89          *
  90          * @param array $array
  91          */
  92         public function setArray( $array ) {
  93                 $this->data = $array;
  94         }
  95
  96         /**
  97          * Returns true if no pages have been added, false otherwise.
  98          *
  99          * @return bool
 100          */
 101         public function isEmpty() {
 102                 return $this->getSize() == 0;
 103         }
 104
 105         /**
 106          * Returns the size of the batch.
 107          *
 108          * @return int
 109          */
 110         public function getSize() {
 111                 return count( $this->data );
 112         }
 113
 114         /**
 115          * Do the query and add the results to the LinkCache object
 116          *
 117          * @return array Mapping PDBK to ID
 118          */
 119         public function execute() {
 120                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
 121
 122                 return $this->executeInto( $linkCache );
 123         }
 124
 125         /**
 126          * Do the query and add the results to a given LinkCache object
 127          * Return an array mapping PDBK to ID
 128          *
 129          * @param LinkCache $cache
 130          * @return array Remaining IDs
 131          */
 132         protected function executeInto( &$cache ) {
 133                 $res = $this->doQuery();
 134                 $this->doGenderQuery();
 135                 $ids = $this->addResultToCache( $cache, $res );
 136
 137                 return $ids;
 138         }
 139
 140         /**
 141          * Add a ResultWrapper containing IDs and titles to a LinkCache object.
 142          * As normal, titles will go into the static Title cache field.
 143          * This function *also* stores extra fields of the title used for link
 144          * parsing to avoid extra DB queries.
 145          *
 146          * @param LinkCache $cache
 147          * @param ResultWrapper $res
 148          * @return array Array of remaining titles
 149          */
 150         public function addResultToCache( $cache, $res ) {
 151                 if ( !$res ) {
 152                         return [];
 153                 }
 154
 155                 $titleFormatter = MediaWikiServices::getInstance()->getTitleFormatter();
 156                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 157
 158                 $ids = [];
 159                 $remaining = $this->data;
 160                 foreach ( $res as $row ) {
 161                         $title = new TitleValue( (int)$row->page_namespace, $row->page_title );
 162                         $cache->addGoodLinkObjFromRow( $title, $row );
 163                         $pdbk = $titleFormatter->getPrefixedDBkey( $title );
 164                         $ids[$pdbk] = $row->page_id;
 165                         unset( $remaining[$row->page_namespace][$row->page_title] );
 166                 }
 167
 168                 // The remaining links in $data are bad links, register them as such
 169                 foreach ( $remaining as $ns => $dbkeys ) {
 170                         foreach ( $dbkeys as $dbkey => $unused ) {
 171                                 $title = new TitleValue( (int)$ns, (string)$dbkey );
 172                                 $cache->addBadLinkObj( $title );
 173                                 $pdbk = $titleFormatter->getPrefixedDBkey( $title );
 174                                 $ids[$pdbk] = 0;
 175                         }
 176                 }
 177
 178                 return $ids;
 179         }
 180
 181         /**
 182          * Perform the existence test query, return a ResultWrapper with page_id fields
 183          * @return bool|ResultWrapper
 184          */
 185         public function doQuery() {
 186                 if ( $this->isEmpty() ) {
 187                         return false;
 188                 }
 189
 190                 // This is similar to LinkHolderArray::replaceInternal
 191                 $dbr = wfGetDB( DB_SLAVE );
 192                 $table = 'page';
 193                 $fields = array_merge(
 194                         LinkCache::getSelectFields(),
 195                         [ 'page_namespace', 'page_title' ]
 196                 );
 197
 198                 $conds = $this->constructSet( 'page', $dbr );
 199
 200                 // Do query
 201                 $caller = __METHOD__;
 202                 if ( strval( $this->caller ) !== '' ) {
 203                         $caller .= " (for {$this->caller})";
 204                 }
 205                 $res = $dbr->select( $table, $fields, $conds, $caller );
 206
 207                 return $res;
 208         }
 209
 210         /**
 211          * Do (and cache) {{GENDER:...}} information for userpages in this LinkBatch
 212          *
 213          * @return bool Whether the query was successful
 214          */
 215         public function doGenderQuery() {
 216                 if ( $this->isEmpty() ) {
 217                         return false;
 218                 }
 219
 220                 global $wgContLang;
 221                 if ( !$wgContLang->needsGenderDistinction() ) {
 222                         return false;
 223                 }
 224
 225                 $genderCache = MediaWikiServices::getInstance()->getGenderCache();
 226                 $genderCache->doLinkBatch( $this->data, $this->caller );
 227
 228                 return true;
 229         }
 230
 231         /**
 232          * Construct a WHERE clause which will match all the given titles.
 233          *
 234          * @param string $prefix The appropriate table's field name prefix ('page', 'pl', etc)
 235          * @param IDatabase $db DatabaseBase object to use
 236          * @return string|bool String with SQL where clause fragment, or false if no items.
 237          */
 238         public function constructSet( $prefix, $db ) {
 239                 return $db->makeWhereFrom2d( $this->data, "{$prefix}_namespace", "{$prefix}_title" );
 240         }
 241 }