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  * @ingroup 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         /**
  16          * For debugging which method is using this class.
  17          */
  18         protected $caller;
  19
  20         function __construct( $arr = array() ) {
  21                 foreach( $arr as $item ) {
  22                         $this->addObj( $item );
  23                 }
  24         }
  25
  26         /**
  27          * Use ->setCaller( __METHOD__ ) to indicate which code is using this
  28          * class. Only used in debugging output.
  29          * @since 1.17
  30          */
  31         public function setCaller( $caller ) {
  32                 $this->caller = $caller;
  33         }
  34
  35         public function addObj( $title ) {
  36                 if ( is_object( $title ) ) {
  37                         $this->add( $title->getNamespace(), $title->getDBkey() );
  38                 } else {
  39                         wfDebug( "Warning: LinkBatch::addObj got invalid title object\n" );
  40                 }
  41         }
  42
  43         public function add( $ns, $dbkey ) {
  44                 if ( $ns < 0 ) {
  45                         return;
  46                 }
  47                 if ( !array_key_exists( $ns, $this->data ) ) {
  48                         $this->data[$ns] = array();
  49                 }
  50
  51                 $this->data[$ns][str_replace( ' ', '_', $dbkey )] = 1;
  52         }
  53
  54         /**
  55          * Set the link list to a given 2-d array
  56          * First key is the namespace, second is the DB key, value arbitrary
  57          */
  58         public function setArray( $array ) {
  59                 $this->data = $array;
  60         }
  61
  62         /**
  63          * Returns true if no pages have been added, false otherwise.
  64          */
  65         public function isEmpty() {
  66                 return ($this->getSize() == 0);
  67         }
  68
  69         /**
  70          * Returns the size of the batch.
  71          */
  72         public function getSize() {
  73                 return count( $this->data );
  74         }
  75
  76         /**
  77          * Do the query and add the results to the LinkCache object
  78          * Return an array mapping PDBK to ID
  79          */
  80          public function execute() {
  81                 $linkCache = LinkCache::singleton();
  82                 return $this->executeInto( $linkCache );
  83          }
  84
  85         /**
  86          * Do the query and add the results to a given LinkCache object
  87          * Return an array mapping PDBK to ID
  88          */
  89         protected function executeInto( &$cache ) {
  90                 wfProfileIn( __METHOD__ );
  91                 $res = $this->doQuery();
  92                 $ids = $this->addResultToCache( $cache, $res );
  93                 wfProfileOut( __METHOD__ );
  94                 return $ids;
  95         }
  96
  97         /**
  98          * Add a ResultWrapper containing IDs and titles to a LinkCache object.
  99          * As normal, titles will go into the static Title cache field.
 100          * This function *also* stores extra fields of the title used for link
 101          * parsing to avoid extra DB queries.
 102          */
 103         public function addResultToCache( $cache, $res ) {
 104                 if ( !$res ) {
 105                         return array();
 106                 }
 107
 108                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 109
 110                 $ids = array();
 111                 $remaining = $this->data;
 112                 while ( $row = $res->fetchObject() ) {
 113                         $title = Title::makeTitle( $row->page_namespace, $row->page_title );
 114                         $cache->addGoodLinkObj( $row->page_id, $title, $row->page_len, $row->page_is_redirect, $row->page_latest );
 115                         $ids[$title->getPrefixedDBkey()] = $row->page_id;
 116                         unset( $remaining[$row->page_namespace][$row->page_title] );
 117                 }
 118
 119                 // The remaining links in $data are bad links, register them as such
 120                 foreach ( $remaining as $ns => $dbkeys ) {
 121                         foreach ( $dbkeys as $dbkey => $unused ) {
 122                                 $title = Title::makeTitle( $ns, $dbkey );
 123                                 $cache->addBadLinkObj( $title );
 124                                 $ids[$title->getPrefixedDBkey()] = 0;
 125                         }
 126                 }
 127                 return $ids;
 128         }
 129
 130         /**
 131          * Perform the existence test query, return a ResultWrapper with page_id fields
 132          */
 133         public function doQuery() {
 134                 if ( $this->isEmpty() ) {
 135                         return false;
 136                 }
 137                 wfProfileIn( __METHOD__ );
 138
 139                 // This is similar to LinkHolderArray::replaceInternal
 140                 $dbr = wfGetDB( DB_SLAVE );
 141                 $table = 'page';
 142                 $fields = array( 'page_id', 'page_namespace', 'page_title', 'page_len',
 143                         'page_is_redirect', 'page_latest' );
 144                 $conds = $this->constructSet( 'page', $dbr );
 145
 146                 // Do query
 147                 $caller = __METHOD__;
 148                 if ( strval( $this->caller ) !== '' ) {
 149                         $caller .= " (for {$this->caller})";
 150                 }
 151                 $res = $dbr->select( $table, $fields, $conds, $caller );
 152                 wfProfileOut( __METHOD__ );
 153                 return $res;
 154         }
 155
 156         /**
 157          * Construct a WHERE clause which will match all the given titles.
 158          *
 159          * @param $prefix String: the appropriate table's field name prefix ('page', 'pl', etc)
 160          * @param $db DatabaseBase object to use
 161          * @return mixed string with SQL where clause fragment, or false if no items.
 162          */
 163         public function constructSet( $prefix, $db ) {
 164                 return $db->makeWhereFrom2d( $this->data, "{$prefix}_namespace", "{$prefix}_title" );
 165         }
 166 }