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          * @return self (since 1.32)
  61          */
  62         public function setCaller( $caller ) {
  63                 $this->caller = $caller;
  64
  65                 return $this;
  66         }
  67
  68         /**
  69          * @param LinkTarget $linkTarget
  70          */
  71         public function addObj( $linkTarget ) {
  72                 if ( is_object( $linkTarget ) ) {
  73                         $this->add( $linkTarget->getNamespace(), $linkTarget->getDBkey() );
  74                 } else {
  75                         wfDebug( "Warning: LinkBatch::addObj got invalid LinkTarget object\n" );
  76                 }
  77         }
  78
  79         /**
  80          * @param int $ns
  81          * @param string $dbkey
  82          */
  83         public function add( $ns, $dbkey ) {
  84                 if ( $ns < 0 || $dbkey === '' ) {
  85                         return; // T137083
  86                 }
  87                 if ( !array_key_exists( $ns, $this->data ) ) {
  88                         $this->data[$ns] = [];
  89                 }
  90
  91                 $this->data[$ns][strtr( $dbkey, ' ', '_' )] = 1;
  92         }
  93
  94         /**
  95          * Set the link list to a given 2-d array
  96          * First key is the namespace, second is the DB key, value arbitrary
  97          *
  98          * @param array $array
  99          */
 100         public function setArray( $array ) {
 101                 $this->data = $array;
 102         }
 103
 104         /**
 105          * Returns true if no pages have been added, false otherwise.
 106          *
 107          * @return bool
 108          */
 109         public function isEmpty() {
 110                 return $this->getSize() == 0;
 111         }
 112
 113         /**
 114          * Returns the size of the batch.
 115          *
 116          * @return int
 117          */
 118         public function getSize() {
 119                 return count( $this->data );
 120         }
 121
 122         /**
 123          * Do the query and add the results to the LinkCache object
 124          *
 125          * @return array Mapping PDBK to ID
 126          */
 127         public function execute() {
 128                 $linkCache = MediaWikiServices::getInstance()->getLinkCache();
 129
 130                 return $this->executeInto( $linkCache );
 131         }
 132
 133         /**
 134          * Do the query and add the results to a given LinkCache object
 135          * Return an array mapping PDBK to ID
 136          *
 137          * @param LinkCache &$cache
 138          * @return array Remaining IDs
 139          */
 140         protected function executeInto( &$cache ) {
 141                 $res = $this->doQuery();
 142                 $this->doGenderQuery();
 143                 $ids = $this->addResultToCache( $cache, $res );
 144
 145                 return $ids;
 146         }
 147
 148         /**
 149          * Add a ResultWrapper containing IDs and titles to a LinkCache object.
 150          * As normal, titles will go into the static Title cache field.
 151          * This function *also* stores extra fields of the title used for link
 152          * parsing to avoid extra DB queries.
 153          *
 154          * @param LinkCache $cache
 155          * @param ResultWrapper $res
 156          * @return array Array of remaining titles
 157          */
 158         public function addResultToCache( $cache, $res ) {
 159                 if ( !$res ) {
 160                         return [];
 161                 }
 162
 163                 $titleFormatter = MediaWikiServices::getInstance()->getTitleFormatter();
 164                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 165
 166                 $ids = [];
 167                 $remaining = $this->data;
 168                 foreach ( $res as $row ) {
 169                         $title = new TitleValue( (int)$row->page_namespace, $row->page_title );
 170                         $cache->addGoodLinkObjFromRow( $title, $row );
 171                         $pdbk = $titleFormatter->getPrefixedDBkey( $title );
 172                         $ids[$pdbk] = $row->page_id;
 173                         unset( $remaining[$row->page_namespace][$row->page_title] );
 174                 }
 175
 176                 // The remaining links in $data are bad links, register them as such
 177                 foreach ( $remaining as $ns => $dbkeys ) {
 178                         foreach ( $dbkeys as $dbkey => $unused ) {
 179                                 $title = new TitleValue( (int)$ns, (string)$dbkey );
 180                                 $cache->addBadLinkObj( $title );
 181                                 $pdbk = $titleFormatter->getPrefixedDBkey( $title );
 182                                 $ids[$pdbk] = 0;
 183                         }
 184                 }
 185
 186                 return $ids;
 187         }
 188
 189         /**
 190          * Perform the existence test query, return a ResultWrapper with page_id fields
 191          * @return bool|ResultWrapper
 192          */
 193         public function doQuery() {
 194                 if ( $this->isEmpty() ) {
 195                         return false;
 196                 }
 197
 198                 // This is similar to LinkHolderArray::replaceInternal
 199                 $dbr = wfGetDB( DB_REPLICA );
 200                 $table = 'page';
 201                 $fields = array_merge(
 202                         LinkCache::getSelectFields(),
 203                         [ 'page_namespace', 'page_title' ]
 204                 );
 205
 206                 $conds = $this->constructSet( 'page', $dbr );
 207
 208                 // Do query
 209                 $caller = __METHOD__;
 210                 if ( strval( $this->caller ) !== '' ) {
 211                         $caller .= " (for {$this->caller})";
 212                 }
 213                 $res = $dbr->select( $table, $fields, $conds, $caller );
 214
 215                 return $res;
 216         }
 217
 218         /**
 219          * Do (and cache) {{GENDER:...}} information for userpages in this LinkBatch
 220          *
 221          * @return bool Whether the query was successful
 222          */
 223         public function doGenderQuery() {
 224                 if ( $this->isEmpty() ) {
 225                         return false;
 226                 }
 227                 $services = MediaWikiServices::getInstance();
 228
 229                 if ( !$services->getContentLanguage()->needsGenderDistinction() ) {
 230                         return false;
 231                 }
 232
 233                 $genderCache = $services->getGenderCache();
 234                 $genderCache->doLinkBatch( $this->data, $this->caller );
 235
 236                 return true;
 237         }
 238
 239         /**
 240          * Construct a WHERE clause which will match all the given titles.
 241          *
 242          * @param string $prefix The appropriate table's field name prefix ('page', 'pl', etc)
 243          * @param IDatabase $db DB object to use
 244          * @return string|bool String with SQL where clause fragment, or false if no items.
 245          */
 246         public function constructSet( $prefix, $db ) {
 247                 return $db->makeWhereFrom2d( $this->data, "{$prefix}_namespace", "{$prefix}_title" );
 248         }
 249 }