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
  25 /**
  26  * Class representing a list of titles
  27  * The execute() method checks them all for existence and adds them to a LinkCache object
  28  *
  29  * @ingroup Cache
  30  */
  31 class LinkBatch {
  32         /**
  33          * 2-d array, first index namespace, second index dbkey, value arbitrary
  34          */
  35         public $data = [];
  36
  37         /**
  38          * For debugging which method is using this class.
  39          */
  40         protected $caller;
  41
  42         function __construct( $arr = [] ) {
  43                 foreach ( $arr as $item ) {
  44                         $this->addObj( $item );
  45                 }
  46         }
  47
  48         /**
  49          * Use ->setCaller( __METHOD__ ) to indicate which code is using this
  50          * class. Only used in debugging output.
  51          * @since 1.17
  52          *
  53          * @param string $caller
  54          */
  55         public function setCaller( $caller ) {
  56                 $this->caller = $caller;
  57         }
  58
  59         /**
  60          * @param LinkTarget $linkTarget
  61          */
  62         public function addObj( $linkTarget ) {
  63                 if ( is_object( $linkTarget ) ) {
  64                         $this->add( $linkTarget->getNamespace(), $linkTarget->getDBkey() );
  65                 } else {
  66                         wfDebug( "Warning: LinkBatch::addObj got invalid LinkTarget object\n" );
  67                 }
  68         }
  69
  70         /**
  71          * @param int $ns
  72          * @param string $dbkey
  73          */
  74         public function add( $ns, $dbkey ) {
  75                 if ( $ns < 0 ) {
  76                         return;
  77                 }
  78                 if ( !array_key_exists( $ns, $this->data ) ) {
  79                         $this->data[$ns] = [];
  80                 }
  81
  82                 $this->data[$ns][strtr( $dbkey, ' ', '_' )] = 1;
  83         }
  84
  85         /**
  86          * Set the link list to a given 2-d array
  87          * First key is the namespace, second is the DB key, value arbitrary
  88          *
  89          * @param array $array
  90          */
  91         public function setArray( $array ) {
  92                 $this->data = $array;
  93         }
  94
  95         /**
  96          * Returns true if no pages have been added, false otherwise.
  97          *
  98          * @return bool
  99          */
 100         public function isEmpty() {
 101                 return $this->getSize() == 0;
 102         }
 103
 104         /**
 105          * Returns the size of the batch.
 106          *
 107          * @return int
 108          */
 109         public function getSize() {
 110                 return count( $this->data );
 111         }
 112
 113         /**
 114          * Do the query and add the results to the LinkCache object
 115          *
 116          * @return array Mapping PDBK to ID
 117          */
 118         public function execute() {
 119                 $linkCache = LinkCache::singleton();
 120
 121                 return $this->executeInto( $linkCache );
 122         }
 123
 124         /**
 125          * Do the query and add the results to a given LinkCache object
 126          * Return an array mapping PDBK to ID
 127          *
 128          * @param LinkCache $cache
 129          * @return array Remaining IDs
 130          */
 131         protected function executeInto( &$cache ) {
 132                 $res = $this->doQuery();
 133                 $this->doGenderQuery();
 134                 $ids = $this->addResultToCache( $cache, $res );
 135
 136                 return $ids;
 137         }
 138
 139         /**
 140          * Add a ResultWrapper containing IDs and titles to a LinkCache object.
 141          * As normal, titles will go into the static Title cache field.
 142          * This function *also* stores extra fields of the title used for link
 143          * parsing to avoid extra DB queries.
 144          *
 145          * @param LinkCache $cache
 146          * @param ResultWrapper $res
 147          * @return array Array of remaining titles
 148          */
 149         public function addResultToCache( $cache, $res ) {
 150                 if ( !$res ) {
 151                         return [];
 152                 }
 153
 154                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 155
 156                 $ids = [];
 157                 $remaining = $this->data;
 158                 foreach ( $res as $row ) {
 159                         $title = Title::makeTitle( $row->page_namespace, $row->page_title );
 160                         $cache->addGoodLinkObjFromRow( $title, $row );
 161                         $ids[$title->getPrefixedDBkey()] = $row->page_id;
 162                         unset( $remaining[$row->page_namespace][$row->page_title] );
 163                 }
 164
 165                 // The remaining links in $data are bad links, register them as such
 166                 foreach ( $remaining as $ns => $dbkeys ) {
 167                         foreach ( $dbkeys as $dbkey => $unused ) {
 168                                 $title = Title::makeTitle( $ns, $dbkey );
 169                                 $cache->addBadLinkObj( $title );
 170                                 $ids[$title->getPrefixedDBkey()] = 0;
 171                         }
 172                 }
 173
 174                 return $ids;
 175         }
 176
 177         /**
 178          * Perform the existence test query, return a ResultWrapper with page_id fields
 179          * @return bool|ResultWrapper
 180          */
 181         public function doQuery() {
 182                 global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 183
 184                 if ( $this->isEmpty() ) {
 185                         return false;
 186                 }
 187
 188                 // This is similar to LinkHolderArray::replaceInternal
 189                 $dbr = wfGetDB( DB_SLAVE );
 190                 $table = 'page';
 191                 $fields = [ 'page_id', 'page_namespace', 'page_title', 'page_len',
 192                         'page_is_redirect', 'page_latest' ];
 193
 194                 if ( $wgContentHandlerUseDB ) {
 195                         $fields[] = 'page_content_model';
 196                 }
 197                 if ( $wgPageLanguageUseDB ) {
 198                         $fields[] = 'page_lang';
 199                 }
 200
 201                 $conds = $this->constructSet( 'page', $dbr );
 202
 203                 // Do query
 204                 $caller = __METHOD__;
 205                 if ( strval( $this->caller ) !== '' ) {
 206                         $caller .= " (for {$this->caller})";
 207                 }
 208                 $res = $dbr->select( $table, $fields, $conds, $caller );
 209
 210                 return $res;
 211         }
 212
 213         /**
 214          * Do (and cache) {{GENDER:...}} information for userpages in this LinkBatch
 215          *
 216          * @return bool Whether the query was successful
 217          */
 218         public function doGenderQuery() {
 219                 if ( $this->isEmpty() ) {
 220                         return false;
 221                 }
 222
 223                 global $wgContLang;
 224                 if ( !$wgContLang->needsGenderDistinction() ) {
 225                         return false;
 226                 }
 227
 228                 $genderCache = GenderCache::singleton();
 229                 $genderCache->doLinkBatch( $this->data, $this->caller );
 230
 231                 return true;
 232         }
 233
 234         /**
 235          * Construct a WHERE clause which will match all the given titles.
 236          *
 237          * @param string $prefix The appropriate table's field name prefix ('page', 'pl', etc)
 238          * @param IDatabase $db DatabaseBase object to use
 239          * @return string|bool String with SQL where clause fragment, or false if no items.
 240          */
 241         public function constructSet( $prefix, $db ) {
 242                 return $db->makeWhereFrom2d( $this->data, "{$prefix}_namespace", "{$prefix}_title" );
 243         }
 244 }