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         /**
  44          * LinkBatch constructor.
  45          * @param LinkTarget[] $arr Initial items to be added to the batch
  46          */
  47         public function __construct( $arr = [] ) {
  48                 foreach ( $arr as $item ) {
  49                         $this->addObj( $item );
  50                 }
  51         }
  52
  53         /**
  54          * Use ->setCaller( __METHOD__ ) to indicate which code is using this
  55          * class. Only used in debugging output.
  56          * @since 1.17
  57          *
  58          * @param string $caller
  59          */
  60         public function setCaller( $caller ) {
  61                 $this->caller = $caller;
  62         }
  63
  64         /**
  65          * @param LinkTarget $linkTarget
  66          */
  67         public function addObj( $linkTarget ) {
  68                 if ( is_object( $linkTarget ) ) {
  69                         $this->add( $linkTarget->getNamespace(), $linkTarget->getDBkey() );
  70                 } else {
  71                         wfDebug( "Warning: LinkBatch::addObj got invalid LinkTarget object\n" );
  72                 }
  73         }
  74
  75         /**
  76          * @param int $ns
  77          * @param string $dbkey
  78          */
  79         public function add( $ns, $dbkey ) {
  80                 if ( $ns < 0 || $dbkey === '' ) {
  81                         return; // T137083
  82                 }
  83                 if ( !array_key_exists( $ns, $this->data ) ) {
  84                         $this->data[$ns] = [];
  85                 }
  86
  87                 $this->data[$ns][strtr( $dbkey, ' ', '_' )] = 1;
  88         }
  89
  90         /**
  91          * Set the link list to a given 2-d array
  92          * First key is the namespace, second is the DB key, value arbitrary
  93          *
  94          * @param array $array
  95          */
  96         public function setArray( $array ) {
  97                 $this->data = $array;
  98         }
  99
 100         /**
 101          * Returns true if no pages have been added, false otherwise.
 102          *
 103          * @return bool
 104          */
 105         public function isEmpty() {
 106                 return $this->getSize() == 0;
 107         }
 108
 109         /**
 110          * Returns the size of the batch.
 111          *
 112          * @return int
 113          */
 114         public function getSize() {
 115                 return count( $this->data );
 116         }
 117
 118         /**
 119          * Do the query and add the results to the LinkCache object
 120          *
 121          * @return array Mapping PDBK to ID
 122          */
 123         public function execute() {
 124                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
 125
 126                 return $this->executeInto( $linkCache );
 127         }
 128
 129         /**
 130          * Do the query and add the results to a given LinkCache object
 131          * Return an array mapping PDBK to ID
 132          *
 133          * @param LinkCache $cache
 134          * @return array Remaining IDs
 135          */
 136         protected function executeInto( &$cache ) {
 137                 $res = $this->doQuery();
 138                 $this->doGenderQuery();
 139                 $ids = $this->addResultToCache( $cache, $res );
 140
 141                 return $ids;
 142         }
 143
 144         /**
 145          * Add a ResultWrapper containing IDs and titles to a LinkCache object.
 146          * As normal, titles will go into the static Title cache field.
 147          * This function *also* stores extra fields of the title used for link
 148          * parsing to avoid extra DB queries.
 149          *
 150          * @param LinkCache $cache
 151          * @param ResultWrapper $res
 152          * @return array Array of remaining titles
 153          */
 154         public function addResultToCache( $cache, $res ) {
 155                 if ( !$res ) {
 156                         return [];
 157                 }
 158
 159                 $titleFormatter = MediaWikiServices::getInstance()->getTitleFormatter();
 160                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 161
 162                 $ids = [];
 163                 $remaining = $this->data;
 164                 foreach ( $res as $row ) {
 165                         $title = new TitleValue( (int)$row->page_namespace, $row->page_title );
 166                         $cache->addGoodLinkObjFromRow( $title, $row );
 167                         $pdbk = $titleFormatter->getPrefixedDBkey( $title );
 168                         $ids[$pdbk] = $row->page_id;
 169                         unset( $remaining[$row->page_namespace][$row->page_title] );
 170                 }
 171
 172                 // The remaining links in $data are bad links, register them as such
 173                 foreach ( $remaining as $ns => $dbkeys ) {
 174                         foreach ( $dbkeys as $dbkey => $unused ) {
 175                                 $title = new TitleValue( (int)$ns, (string)$dbkey );
 176                                 $cache->addBadLinkObj( $title );
 177                                 $pdbk = $titleFormatter->getPrefixedDBkey( $title );
 178                                 $ids[$pdbk] = 0;
 179                         }
 180                 }
 181
 182                 return $ids;
 183         }
 184
 185         /**
 186          * Perform the existence test query, return a ResultWrapper with page_id fields
 187          * @return bool|ResultWrapper
 188          */
 189         public function doQuery() {
 190                 if ( $this->isEmpty() ) {
 191                         return false;
 192                 }
 193
 194                 // This is similar to LinkHolderArray::replaceInternal
 195                 $dbr = wfGetDB( DB_REPLICA );
 196                 $table = 'page';
 197                 $fields = array_merge(
 198                         LinkCache::getSelectFields(),
 199                         [ 'page_namespace', 'page_title' ]
 200                 );
 201
 202                 $conds = $this->constructSet( 'page', $dbr );
 203
 204                 // Do query
 205                 $caller = __METHOD__;
 206                 if ( strval( $this->caller ) !== '' ) {
 207                         $caller .= " (for {$this->caller})";
 208                 }
 209                 $res = $dbr->select( $table, $fields, $conds, $caller );
 210
 211                 return $res;
 212         }
 213
 214         /**
 215          * Do (and cache) {{GENDER:...}} information for userpages in this LinkBatch
 216          *
 217          * @return bool Whether the query was successful
 218          */
 219         public function doGenderQuery() {
 220                 if ( $this->isEmpty() ) {
 221                         return false;
 222                 }
 223
 224                 global $wgContLang;
 225                 if ( !$wgContLang->needsGenderDistinction() ) {
 226                         return false;
 227                 }
 228
 229                 $genderCache = MediaWikiServices::getInstance()->getGenderCache();
 230                 $genderCache->doLinkBatch( $this->data, $this->caller );
 231
 232                 return true;
 233         }
 234
 235         /**
 236          * Construct a WHERE clause which will match all the given titles.
 237          *
 238          * @param string $prefix The appropriate table's field name prefix ('page', 'pl', etc)
 239          * @param IDatabase $db DB object to use
 240          * @return string|bool String with SQL where clause fragment, or false if no items.
 241          */
 242         public function constructSet( $prefix, $db ) {
 243                 return $db->makeWhereFrom2d( $this->data, "{$prefix}_namespace", "{$prefix}_title" );
 244         }
 245 }