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         /**
  36          * @param  $title Title
  37          * @return void
  38          */
  39         public function addObj( $title ) {
  40                 if ( is_object( $title ) ) {
  41                         $this->add( $title->getNamespace(), $title->getDBkey() );
  42                 } else {
  43                         wfDebug( "Warning: LinkBatch::addObj got invalid title object\n" );
  44                 }
  45         }
  46
  47         public function add( $ns, $dbkey ) {
  48                 if ( $ns < 0 ) {
  49                         return;
  50                 }
  51                 if ( !array_key_exists( $ns, $this->data ) ) {
  52                         $this->data[$ns] = array();
  53                 }
  54
  55                 $this->data[$ns][str_replace( ' ', '_', $dbkey )] = 1;
  56         }
  57
  58         /**
  59          * Set the link list to a given 2-d array
  60          * First key is the namespace, second is the DB key, value arbitrary
  61          */
  62         public function setArray( $array ) {
  63                 $this->data = $array;
  64         }
  65
  66         /**
  67          * Returns true if no pages have been added, false otherwise.
  68          */
  69         public function isEmpty() {
  70                 return ($this->getSize() == 0);
  71         }
  72
  73         /**
  74          * Returns the size of the batch.
  75          */
  76         public function getSize() {
  77                 return count( $this->data );
  78         }
  79
  80         /**
  81          * Do the query and add the results to the LinkCache object
  82          * Return an array mapping PDBK to ID
  83          */
  84          public function execute() {
  85                 $linkCache = LinkCache::singleton();
  86                 return $this->executeInto( $linkCache );
  87          }
  88
  89         /**
  90          * Do the query and add the results to a given LinkCache object
  91          * Return an array mapping PDBK to ID
  92          */
  93         protected function executeInto( &$cache ) {
  94                 wfProfileIn( __METHOD__ );
  95                 $res = $this->doQuery();
  96                 $ids = $this->addResultToCache( $cache, $res );
  97                 wfProfileOut( __METHOD__ );
  98                 return $ids;
  99         }
 100
 101         /**
 102          * Add a ResultWrapper containing IDs and titles to a LinkCache object.
 103          * As normal, titles will go into the static Title cache field.
 104          * This function *also* stores extra fields of the title used for link
 105          * parsing to avoid extra DB queries.
 106          */
 107         public function addResultToCache( $cache, $res ) {
 108                 if ( !$res ) {
 109                         return array();
 110                 }
 111
 112                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 113
 114                 $ids = array();
 115                 $remaining = $this->data;
 116                 foreach ( $res as $row ) {
 117                         $title = Title::makeTitle( $row->page_namespace, $row->page_title );
 118                         $cache->addGoodLinkObj( $row->page_id, $title, $row->page_len, $row->page_is_redirect, $row->page_latest );
 119                         $ids[$title->getPrefixedDBkey()] = $row->page_id;
 120                         unset( $remaining[$row->page_namespace][$row->page_title] );
 121                 }
 122
 123                 // The remaining links in $data are bad links, register them as such
 124                 foreach ( $remaining as $ns => $dbkeys ) {
 125                         foreach ( $dbkeys as $dbkey => $unused ) {
 126                                 $title = Title::makeTitle( $ns, $dbkey );
 127                                 $cache->addBadLinkObj( $title );
 128                                 $ids[$title->getPrefixedDBkey()] = 0;
 129                         }
 130                 }
 131                 return $ids;
 132         }
 133
 134         /**
 135          * Perform the existence test query, return a ResultWrapper with page_id fields
 136          */
 137         public function doQuery() {
 138                 if ( $this->isEmpty() ) {
 139                         return false;
 140                 }
 141                 wfProfileIn( __METHOD__ );
 142
 143                 // This is similar to LinkHolderArray::replaceInternal
 144                 $dbr = wfGetDB( DB_SLAVE );
 145                 $table = 'page';
 146                 $fields = array( 'page_id', 'page_namespace', 'page_title', 'page_len',
 147                         'page_is_redirect', 'page_latest' );
 148                 $conds = $this->constructSet( 'page', $dbr );
 149
 150                 // Do query
 151                 $caller = __METHOD__;
 152                 if ( strval( $this->caller ) !== '' ) {
 153                         $caller .= " (for {$this->caller})";
 154                 }
 155                 $res = $dbr->select( $table, $fields, $conds, $caller );
 156                 wfProfileOut( __METHOD__ );
 157                 return $res;
 158         }
 159
 160         /**
 161          * Construct a WHERE clause which will match all the given titles.
 162          *
 163          * @param $prefix String: the appropriate table's field name prefix ('page', 'pl', etc)
 164          * @param $db DatabaseBase object to use
 165          * @return mixed string with SQL where clause fragment, or false if no items.
 166          */
 167         public function constructSet( $prefix, $db ) {
 168                 return $db->makeWhereFrom2d( $this->data, "{$prefix}_namespace", "{$prefix}_title" );
 169         }
 170 }