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 use Wikimedia\Rdbms\ResultWrapper;
  26 use Wikimedia\Rdbms\IDatabase;
  27
  28 /**
  29  * Class representing a list of titles
  30  * The execute() method checks them all for existence and adds them to a LinkCache object
  31  *
  32  * @ingroup Cache
  33  */
  34 class LinkBatch {
  35         /**
  36          * 2-d array, first index namespace, second index dbkey, value arbitrary
  37          */
  38         public $data = [];
  39
  40         /**
  41          * For debugging which method is using this class.
  42          */
  43         protected $caller;
  44
  45         /**
  46          * LinkBatch constructor.
  47          * @param LinkTarget[] $arr Initial items to be added to the batch
  48          */
  49         public function __construct( $arr = [] ) {
  50                 foreach ( $arr as $item ) {
  51                         $this->addObj( $item );
  52                 }
  53         }
  54
  55         /**
  56          * Use ->setCaller( __METHOD__ ) to indicate which code is using this
  57          * class. Only used in debugging output.
  58          * @since 1.17
  59          *
  60          * @param string $caller
  61          */
  62         public function setCaller( $caller ) {
  63                 $this->caller = $caller;
  64         }
  65
  66         /**
  67          * @param LinkTarget $linkTarget
  68          */
  69         public function addObj( $linkTarget ) {
  70                 if ( is_object( $linkTarget ) ) {
  71                         $this->add( $linkTarget->getNamespace(), $linkTarget->getDBkey() );
  72                 } else {
  73                         wfDebug( "Warning: LinkBatch::addObj got invalid LinkTarget object\n" );
  74                 }
  75         }
  76
  77         /**
  78          * @param int $ns
  79          * @param string $dbkey
  80          */
  81         public function add( $ns, $dbkey ) {
  82                 if ( $ns < 0 || $dbkey === '' ) {
  83                         return; // T137083
  84                 }
  85                 if ( !array_key_exists( $ns, $this->data ) ) {
  86                         $this->data[$ns] = [];
  87                 }
  88
  89                 $this->data[$ns][strtr( $dbkey, ' ', '_' )] = 1;
  90         }
  91
  92         /**
  93          * Set the link list to a given 2-d array
  94          * First key is the namespace, second is the DB key, value arbitrary
  95          *
  96          * @param array $array
  97          */
  98         public function setArray( $array ) {
  99                 $this->data = $array;
 100         }
 101
 102         /**
 103          * Returns true if no pages have been added, false otherwise.
 104          *
 105          * @return bool
 106          */
 107         public function isEmpty() {
 108                 return $this->getSize() == 0;
 109         }
 110
 111         /**
 112          * Returns the size of the batch.
 113          *
 114          * @return int
 115          */
 116         public function getSize() {
 117                 return count( $this->data );
 118         }
 119
 120         /**
 121          * Do the query and add the results to the LinkCache object
 122          *
 123          * @return array Mapping PDBK to ID
 124          */
 125         public function execute() {
 126                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
 127
 128                 return $this->executeInto( $linkCache );
 129         }
 130
 131         /**
 132          * Do the query and add the results to a given LinkCache object
 133          * Return an array mapping PDBK to ID
 134          *
 135          * @param LinkCache $cache
 136          * @return array Remaining IDs
 137          */
 138         protected function executeInto( &$cache ) {
 139                 $res = $this->doQuery();
 140                 $this->doGenderQuery();
 141                 $ids = $this->addResultToCache( $cache, $res );
 142
 143                 return $ids;
 144         }
 145
 146         /**
 147          * Add a ResultWrapper containing IDs and titles to a LinkCache object.
 148          * As normal, titles will go into the static Title cache field.
 149          * This function *also* stores extra fields of the title used for link
 150          * parsing to avoid extra DB queries.
 151          *
 152          * @param LinkCache $cache
 153          * @param ResultWrapper $res
 154          * @return array Array of remaining titles
 155          */
 156         public function addResultToCache( $cache, $res ) {
 157                 if ( !$res ) {
 158                         return [];
 159                 }
 160
 161                 $titleFormatter = MediaWikiServices::getInstance()->getTitleFormatter();
 162                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 163
 164                 $ids = [];
 165                 $remaining = $this->data;
 166                 foreach ( $res as $row ) {
 167                         $title = new TitleValue( (int)$row->page_namespace, $row->page_title );
 168                         $cache->addGoodLinkObjFromRow( $title, $row );
 169                         $pdbk = $titleFormatter->getPrefixedDBkey( $title );
 170                         $ids[$pdbk] = $row->page_id;
 171                         unset( $remaining[$row->page_namespace][$row->page_title] );
 172                 }
 173
 174                 // The remaining links in $data are bad links, register them as such
 175                 foreach ( $remaining as $ns => $dbkeys ) {
 176                         foreach ( $dbkeys as $dbkey => $unused ) {
 177                                 $title = new TitleValue( (int)$ns, (string)$dbkey );
 178                                 $cache->addBadLinkObj( $title );
 179                                 $pdbk = $titleFormatter->getPrefixedDBkey( $title );
 180                                 $ids[$pdbk] = 0;
 181                         }
 182                 }
 183
 184                 return $ids;
 185         }
 186
 187         /**
 188          * Perform the existence test query, return a ResultWrapper with page_id fields
 189          * @return bool|ResultWrapper
 190          */
 191         public function doQuery() {
 192                 if ( $this->isEmpty() ) {
 193                         return false;
 194                 }
 195
 196                 // This is similar to LinkHolderArray::replaceInternal
 197                 $dbr = wfGetDB( DB_REPLICA );
 198                 $table = 'page';
 199                 $fields = array_merge(
 200                         LinkCache::getSelectFields(),
 201                         [ 'page_namespace', 'page_title' ]
 202                 );
 203
 204                 $conds = $this->constructSet( 'page', $dbr );
 205
 206                 // Do query
 207                 $caller = __METHOD__;
 208                 if ( strval( $this->caller ) !== '' ) {
 209                         $caller .= " (for {$this->caller})";
 210                 }
 211                 $res = $dbr->select( $table, $fields, $conds, $caller );
 212
 213                 return $res;
 214         }
 215
 216         /**
 217          * Do (and cache) {{GENDER:...}} information for userpages in this LinkBatch
 218          *
 219          * @return bool Whether the query was successful
 220          */
 221         public function doGenderQuery() {
 222                 if ( $this->isEmpty() ) {
 223                         return false;
 224                 }
 225
 226                 global $wgContLang;
 227                 if ( !$wgContLang->needsGenderDistinction() ) {
 228                         return false;
 229                 }
 230
 231                 $genderCache = MediaWikiServices::getInstance()->getGenderCache();
 232                 $genderCache->doLinkBatch( $this->data, $this->caller );
 233
 234                 return true;
 235         }
 236
 237         /**
 238          * Construct a WHERE clause which will match all the given titles.
 239          *
 240          * @param string $prefix The appropriate table's field name prefix ('page', 'pl', etc)
 241          * @param IDatabase $db DB object to use
 242          * @return string|bool String with SQL where clause fragment, or false if no items.
 243          */
 244         public function constructSet( $prefix, $db ) {
 245                 return $db->makeWhereFrom2d( $this->data, "{$prefix}_namespace", "{$prefix}_title" );
 246         }
 247 }