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
  24 /**
  25  * Class representing a list of titles
  26  * The execute() method checks them all for existence and adds them to a LinkCache object
  27  *
  28  * @ingroup Cache
  29  */
  30 class LinkBatch {
  31         /**
  32          * 2-d array, first index namespace, second index dbkey, value arbitrary
  33          */
  34         var $data = array();
  35
  36         /**
  37          * For debugging which method is using this class.
  38          */
  39         protected $caller;
  40
  41         function __construct( $arr = array() ) {
  42                 foreach( $arr as $item ) {
  43                         $this->addObj( $item );
  44                 }
  45         }
  46
  47         /**
  48          * Use ->setCaller( __METHOD__ ) to indicate which code is using this
  49          * class. Only used in debugging output.
  50          * @since 1.17
  51          *
  52          * @param $caller
  53          */
  54         public function setCaller( $caller ) {
  55                 $this->caller = $caller;
  56         }
  57
  58         /**
  59          * @param $title Title
  60          */
  61         public function addObj( $title ) {
  62                 if ( is_object( $title ) ) {
  63                         $this->add( $title->getNamespace(), $title->getDBkey() );
  64                 } else {
  65                         wfDebug( "Warning: LinkBatch::addObj got invalid title object\n" );
  66                 }
  67         }
  68
  69         /**
  70          * @param $ns int
  71          * @param $dbkey string
  72          * @return mixed
  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] = array();
  80                 }
  81
  82                 $this->data[$ns][str_replace( ' ', '_', $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                 return $this->executeInto( $linkCache );
 121         }
 122
 123         /**
 124          * Do the query and add the results to a given LinkCache object
 125          * Return an array mapping PDBK to ID
 126          *
 127          * @param $cache LinkCache
 128          * @return Array remaining IDs
 129          */
 130         protected function executeInto( &$cache ) {
 131                 wfProfileIn( __METHOD__ );
 132                 $res = $this->doQuery();
 133                 $this->doGenderQuery();
 134                 $ids = $this->addResultToCache( $cache, $res );
 135                 wfProfileOut( __METHOD__ );
 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 $cache LinkCache
 146          * @param $res
 147          * @return Array of remaining titles
 148          */
 149         public function addResultToCache( $cache, $res ) {
 150                 if ( !$res ) {
 151                         return array();
 152                 }
 153
 154                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 155
 156                 $ids = array();
 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                 return $ids;
 174         }
 175
 176         /**
 177          * Perform the existence test query, return a ResultWrapper with page_id fields
 178          * @return Bool|ResultWrapper
 179          */
 180         public function doQuery() {
 181                 if ( $this->isEmpty() ) {
 182                         return false;
 183                 }
 184                 wfProfileIn( __METHOD__ );
 185
 186                 // This is similar to LinkHolderArray::replaceInternal
 187                 $dbr = wfGetDB( DB_SLAVE );
 188                 $table = 'page';
 189                 $fields = array( 'page_id', 'page_namespace', 'page_title', 'page_len',
 190                         'page_is_redirect', 'page_latest' );
 191                 $conds = $this->constructSet( 'page', $dbr );
 192
 193                 // Do query
 194                 $caller = __METHOD__;
 195                 if ( strval( $this->caller ) !== '' ) {
 196                         $caller .= " (for {$this->caller})";
 197                 }
 198                 $res = $dbr->select( $table, $fields, $conds, $caller );
 199                 wfProfileOut( __METHOD__ );
 200                 return $res;
 201         }
 202
 203         /**
 204          * Do (and cache) {{GENDER:...}} information for userpages in this LinkBatch
 205          *
 206          * @return bool whether the query was successful
 207          */
 208         public function doGenderQuery() {
 209                 if ( $this->isEmpty() ) {
 210                         return false;
 211                 }
 212
 213                 global $wgContLang;
 214                 if ( !$wgContLang->needsGenderDistinction() ) {
 215                         return false;
 216                 }
 217
 218                 $genderCache = GenderCache::singleton();
 219                 $genderCache->doLinkBatch( $this->data, $this->caller );
 220                 return true;
 221         }
 222
 223         /**
 224          * Construct a WHERE clause which will match all the given titles.
 225          *
 226          * @param $prefix String: the appropriate table's field name prefix ('page', 'pl', etc)
 227          * @param $db DatabaseBase object to use
 228          * @return mixed string with SQL where clause fragment, or false if no items.
 229          */
 230         public function constructSet( $prefix, $db ) {
 231                 return $db->makeWhereFrom2d( $this->data, "{$prefix}_namespace", "{$prefix}_title" );
 232         }
 233 }