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  * @addtogroup Cache
   8  */
   9 class LinkBatch {
  10         /**
  11          * 2-d array, first index namespace, second index dbkey, value arbitrary
  12          */
  13         var $data = array();
  14
  15         function __construct( $arr = array() ) {
  16                 foreach( $arr as $item ) {
  17                         $this->addObj( $item );
  18                 }
  19         }
  20
  21         function addObj( $title ) {
  22                 if ( is_object( $title ) ) {
  23                         $this->add( $title->getNamespace(), $title->getDBkey() );
  24                 } else {
  25                         wfDebug( "Warning: LinkBatch::addObj got invalid title object\n" );
  26                 }
  27         }
  28
  29         function add( $ns, $dbkey ) {
  30                 if ( $ns < 0 ) {
  31                         return;
  32                 }
  33                 if ( !array_key_exists( $ns, $this->data ) ) {
  34                         $this->data[$ns] = array();
  35                 }
  36
  37                 $this->data[$ns][$dbkey] = 1;
  38         }
  39
  40         /**
  41          * Set the link list to a given 2-d array
  42          * First key is the namespace, second is the DB key, value arbitrary
  43          */
  44         function setArray( $array ) {
  45                 $this->data = $array;
  46         }
  47
  48         /**
  49          * Returns true if no pages have been added, false otherwise.
  50          */
  51         function isEmpty() {
  52                 return ($this->getSize() == 0);
  53         }
  54
  55         /**
  56          * Returns the size of the batch.
  57          */
  58         function getSize() {
  59                 return count( $this->data );
  60         }
  61
  62         /**
  63          * Do the query and add the results to the LinkCache object
  64          * Return an array mapping PDBK to ID
  65          */
  66          function execute() {
  67                 $linkCache =& LinkCache::singleton();
  68                 return $this->executeInto( $linkCache );
  69          }
  70
  71         /**
  72          * Do the query and add the results to a given LinkCache object
  73          * Return an array mapping PDBK to ID
  74          */
  75         function executeInto( &$cache ) {
  76                 $fname = 'LinkBatch::executeInto';
  77                 wfProfileIn( $fname );
  78                 // Do query
  79                 $res = $this->doQuery();
  80                 if ( !$res ) {
  81                         wfProfileOut( $fname );
  82                         return array();
  83                 }
  84
  85                 // For each returned entry, add it to the list of good links, and remove it from $remaining
  86
  87                 $ids = array();
  88                 $remaining = $this->data;
  89                 while ( $row = $res->fetchObject() ) {
  90                         $title = Title::makeTitle( $row->page_namespace, $row->page_title );
  91                         $cache->addGoodLinkObj( $row->page_id, $title );
  92                         $ids[$title->getPrefixedDBkey()] = $row->page_id;
  93                         unset( $remaining[$row->page_namespace][$row->page_title] );
  94                 }
  95                 $res->free();
  96
  97                 // The remaining links in $data are bad links, register them as such
  98                 foreach ( $remaining as $ns => $dbkeys ) {
  99                         foreach ( $dbkeys as $dbkey => $unused ) {
 100                                 $title = Title::makeTitle( $ns, $dbkey );
 101                                 $cache->addBadLinkObj( $title );
 102                                 $ids[$title->getPrefixedDBkey()] = 0;
 103                         }
 104                 }
 105                 wfProfileOut( $fname );
 106                 return $ids;
 107         }
 108
 109         /**
 110          * Perform the existence test query, return a ResultWrapper with page_id fields
 111          */
 112         function doQuery() {
 113                 $fname = 'LinkBatch::doQuery';
 114
 115                 if ( $this->isEmpty() ) {
 116                         return false;
 117                 }
 118                 wfProfileIn( $fname );
 119
 120                 // Construct query
 121                 // This is very similar to Parser::replaceLinkHolders
 122                 $dbr = wfGetDB( DB_SLAVE );
 123                 $page = $dbr->tableName( 'page' );
 124                 $set = $this->constructSet( 'page', $dbr );
 125                 if ( $set === false ) {
 126                         wfProfileOut( $fname );
 127                         return false;
 128                 }
 129                 $sql = "SELECT page_id, page_namespace, page_title FROM $page WHERE $set";
 130
 131                 // Do query
 132                 $res = new ResultWrapper( $dbr,  $dbr->query( $sql, $fname ) );
 133                 wfProfileOut( $fname );
 134                 return $res;
 135         }
 136
 137         /**
 138          * Construct a WHERE clause which will match all the given titles.
 139          * Give the appropriate table's field name prefix ('page', 'pl', etc).
 140          *
 141          * @param $prefix String: ??
 142          * @return string
 143          * @public
 144          */
 145         function constructSet( $prefix, &$db ) {
 146                 $first = true;
 147                 $firstTitle = true;
 148                 $sql = '';
 149                 foreach ( $this->data as $ns => $dbkeys ) {
 150                         if ( !count( $dbkeys ) ) {
 151                                 continue;
 152                         }
 153
 154                         if ( $first ) {
 155                                 $first = false;
 156                         } else {
 157                                 $sql .= ' OR ';
 158                         }
 159
 160                         if (count($dbkeys)==1) { // avoid multiple-reference syntax if simple equality can be used
 161
 162                                 $sql .= "({$prefix}_namespace=$ns AND {$prefix}_title=".
 163                                         $db->addQuotes(current(array_keys($dbkeys))).
 164                                         ")";
 165                         } else {
 166                                 $sql .= "({$prefix}_namespace=$ns AND {$prefix}_title IN (";
 167
 168                                 $firstTitle = true;
 169                                 foreach( $dbkeys as $dbkey => $unused ) {
 170                                         if ( $firstTitle ) {
 171                                                 $firstTitle = false;
 172                                         } else {
 173                                                 $sql .= ',';
 174                                         }
 175                                         $sql .= $db->addQuotes( $dbkey );
 176                                 }
 177                                 $sql .= '))';
 178                         }
 179                 }
 180                 if ( $first && $firstTitle ) {
 181                         # No titles added
 182                         return false;
 183                 } else {
 184                         return $sql;
 185                 }
 186         }
 187 }
 188
 189 ?>