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