includes/LinkBatch.php

   1 <?php
   2
   3 /**
   4  * Class representing a list of titles
   5  * The execute() method checks them all for existence and adds them to a LinkCache object
   6  +
   7  * @package MediaWiki
   8  * @subpackage Cache
   9  */
  10 class LinkBatch {
  11         /**
  12          * 2-d array, first index namespace, second index dbkey, value arbitrary
  13          */
  14         var $data = array();
  15
  16         function LinkBatch( $arr = array() ) {
  17                 foreach( $arr as $item ) {
  18                         $this->addObj( $item );
  19                 }
  20         }
  21
  22         function addObj( $title ) {
  23                 if ( is_object( $title ) ) {
  24                         $this->add( $title->getNamespace(), $title->getDBkey() );
  25                 } else {
  26                         wfDebug( "Warning: LinkBatch::addObj got invalid title object\n" );
  27                 }
  28         }
  29
  30         function add( $ns, $dbkey ) {
  31                 if ( $ns < 0 ) {
  32                         return;
  33                 }
  34                 if ( !array_key_exists( $ns, $this->data ) ) {
  35                         $this->data[$ns] = array();
  36                 }
  37
  38                 $this->data[$ns][$dbkey] = 1;
  39         }
  40
  41         /**
  42          * Set the link list to a given 2-d array
  43          * First key is the namespace, second is the DB key, value arbitrary
  44          */
  45         function setArray( $array ) {
  46                 $this->data = $array;
  47         }
  48
  49         /**
  50          * Returns true if no pages have been added, false otherwise.
  51          */
  52         function isEmpty() {
  53                 return ($this->getSize() == 0);
  54         }
  55
  56         /**
  57          * Returns the size of the batch.
  58          */
  59         function getSize() {
  60                 return count( $this->data );
  61         }
  62
  63         /**
  64          * Do the query and add the results to the LinkCache object
  65          * Return an array mapping PDBK to ID
  66          */
  67          function execute() {
  68                 $linkCache =& LinkCache::singleton();
  69                 return $this->executeInto( $linkCache );
  70          }
  71
  72         /**
  73          * Do the query and add the results to a given LinkCache object
  74          * Return an array mapping PDBK to ID
  75          */
  76         function executeInto( &$cache ) {
  77                 $fname = 'LinkBatch::executeInto';
  78                 wfProfileIn( $fname );
  79                 // Do query
  80                 $res = $this->doQuery();
  81                 if ( !$res ) {
  82                         wfProfileOut( $fname );
  83                         return array();
  84                 }
  85
  86                 // For each returned entry, add it to the list of good links, and remove it from $remaining
  87
  88                 $ids = array();
  89                 $remaining = $this->data;
  90                 while ( $row = $res->fetchObject() ) {
  91                         $title = Title::makeTitle( $row->page_namespace, $row->page_title );
  92                         $cache->addGoodLinkObj( $row->page_id, $title );
  93                         $ids[$title->getPrefixedDBkey()] = $row->page_id;
  94                         unset( $remaining[$row->page_namespace][$row->page_title] );
  95                 }
  96                 $res->free();
  97
  98                 // The remaining links in $data are bad links, register them as such
  99                 foreach ( $remaining as $ns => $dbkeys ) {
 100                         foreach ( $dbkeys as $dbkey => $unused ) {
 101                                 $title = Title::makeTitle( $ns, $dbkey );
 102                                 $cache->addBadLinkObj( $title );
 103                                 $ids[$title->getPrefixedDBkey()] = 0;
 104                         }
 105                 }
 106                 wfProfileOut( $fname );
 107                 return $ids;
 108         }
 109
 110         /**
 111          * Perform the existence test query, return a ResultWrapper with page_id fields
 112          */
 113         function doQuery() {
 114                 $fname = 'LinkBatch::doQuery';
 115
 116                 if ( $this->isEmpty() ) {
 117                         return false;
 118                 }
 119                 wfProfileIn( $fname );
 120
 121                 // Construct query
 122                 // This is very similar to Parser::replaceLinkHolders
 123                 $dbr =& wfGetDB( DB_SLAVE );
 124                 $page = $dbr->tableName( 'page' );
 125                 $set = $this->constructSet( 'page', $dbr );
 126                 if ( $set === false ) {
 127                         wfProfileOut( $fname );
 128                         return false;
 129                 }
 130                 $sql = "SELECT page_id, page_namespace, page_title FROM $page WHERE $set";
 131
 132                 // Do query
 133                 $res = new ResultWrapper( $dbr,  $dbr->query( $sql, $fname ) );
 134                 wfProfileOut( $fname );
 135                 return $res;
 136         }
 137
 138         /**
 139          * Construct a WHERE clause which will match all the given titles.
 140          * Give the appropriate table's field name prefix ('page', 'pl', etc).
 141          *
 142          * @param $prefix String: ??
 143          * @return string
 144          * @public
 145          */
 146         function constructSet( $prefix, &$db ) {
 147                 $first = true;
 148                 $firstTitle = true;
 149                 $sql = '';
 150                 foreach ( $this->data as $ns => $dbkeys ) {
 151                         if ( !count( $dbkeys ) ) {
 152                                 continue;
 153                         }
 154
 155                         if ( $first ) {
 156                                 $first = false;
 157                         } else {
 158                                 $sql .= ' OR ';
 159                         }
 160                         $sql .= "({$prefix}_namespace=$ns AND {$prefix}_title IN (";
 161
 162                         $firstTitle = true;
 163                         foreach( $dbkeys as $dbkey => $unused ) {
 164                                 if ( $firstTitle ) {
 165                                         $firstTitle = false;
 166                                 } else {
 167                                         $sql .= ',';
 168                                 }
 169                                 $sql .= $db->addQuotes( $dbkey );
 170                         }
 171
 172                         $sql .= '))';
 173                 }
 174                 if ( $first && $firstTitle ) {
 175                         # No titles added
 176                         return false;
 177                 } else {
 178                         return $sql;
 179                 }
 180         }
 181 }
 182
 183 ?>