Making INNER JOIN implicit

[lhc/web/wiklou.git] / includes / SpecialRandompage.php

diff --git a/includes/SpecialRandompage.php b/includes/SpecialRandompage.php
index 051c9f9..1ba8e98 100644 (file)
--- a/includes/SpecialRandompage.php
+++ b/includes/SpecialRandompage.php
@@ -9,59 +9,68 @@
  */
 
 /**
- * Main execution point
- * @param $par Namespace to select the page from
+ * Special page to direct the user to a random page
+ *
+ * @addtogroup SpecialPage
  */
-function wfSpecialRandompage( $par = null ) {
-       global $wgOut, $wgContLang;
-
-       $rnd = new RandomPage();
-       $rnd->setNamespace( $wgContLang->getNsIndex( $par ) );
-       $rnd->setRedirect( false );
-
-       $title = $rnd->getRandomTitle();
+class RandomPage extends SpecialPage {
+       private $namespace = NS_MAIN;  // namespace to select pages from
 
-       if( is_null( $title ) ) {
-               $wgOut->addWikiText( wfMsg( 'randompage-nopages' ) );
-               return;
+       function __construct( $name = 'Randompage' ){
+               parent::__construct( $name );
        }
 
-       $wgOut->reportTime();
-       $wgOut->redirect( $title->getFullUrl() );
-}
-
-
-class RandomPage {
-       private $namespace = NS_MAIN;  // namespace to select pages from
-       private $redirect = false;     // select redirects instead of normal pages?
-
-       public function getNamespace ( ) {
+       public function getNamespace() {
                return $this->namespace;
        }
+
        public function setNamespace ( $ns ) {
                if( $ns < NS_MAIN ) $ns = NS_MAIN;
                $this->namespace = $ns;
        }
-       public function getRedirect ( ) {
-               return $this->redirect;
+
+       // select redirects instead of normal pages?
+       // Overriden by SpecialRandomredirect
+       public function isRedirect(){
+               return false;
        }
-       public function setRedirect ( $redirect ) {
-               $this->redirect = $redirect;
+
+       public function execute( $par ) {
+               global $wgOut, $wgContLang;
+
+               if ($par)
+                       $this->setNamespace( $wgContLang->getNsIndex( $par ) );
+
+               $title = $this->getRandomTitle();
+
+               if( is_null( $title ) ) {
+                       $this->setHeaders();
+                       $wgOut->addWikiMsg( strtolower( $this->mName ) . '-nopages' );
+                       return;
+               }
+
+               $query = $this->isRedirect() ? 'redirect=no' : '';
+               $wgOut->redirect( $title->getFullUrl( $query ) );
        }
 
+
        /**
         * Choose a random title.
         * @return Title object (or null if nothing to choose from)
         */
-       public function getRandomTitle ( ) {
+       public function getRandomTitle() {
                $randstr = wfRandom();
                $row = $this->selectRandomPageFromDB( $randstr );
 
-               if( !$row ) {
-                       // Try again with a normalized value
-                       $randstr = wfRandom( $this->getMaxPageRandom() );
-                       $row = $this->selectRandomPageFromDB( $randstr );
-               }
+               /* If we picked a value that was higher than any in
+                * the DB, wrap around and select the page with the
+                * lowest value instead!  One might think this would
+                * skew the distribution, but in fact it won't cause
+                * any more bias than what the page_random scheme
+                * causes anyway.  Trust me, I'm a mathematician. :)
+                */
+               if( !$row )
+                       $row = $this->selectRandomPageFromDB( "0" );
 
                if( $row )
                        return Title::makeTitleSafe( $this->namespace, $row->page_title );
@@ -69,54 +78,29 @@ class RandomPage {
                        return null;
        }
 
-       private function selectRandomPageFromDB ( $randstr ) {
+       private function selectRandomPageFromDB( $randstr ) {
                global $wgExtraRandompageSQL;
                $fname = 'RandomPage::selectRandomPageFromDB';
 
                $dbr = wfGetDB( DB_SLAVE );
 
-               $from = $this->getSQLFrom( $dbr );
-               $where = $this->getSQLWhere( $dbr );
+               $use_index = $dbr->useIndexClause( 'page_random' );
+               $page = $dbr->tableName( 'page' );
 
-               $sql = "SELECT page_title FROM $from
-                       WHERE $where AND page_random > $randstr
+               $ns = (int) $this->namespace;
+               $redirect = $this->isRedirect() ? 1 : 0;
+
+               $extra = $wgExtraRandompageSQL ? "AND ($wgExtraRandompageSQL)" : "";
+               $sql = "SELECT page_title
+                       FROM $page $use_index
+                       WHERE page_namespace = $ns
+                       AND page_is_redirect = $redirect
+                       AND page_random >= $randstr
+                       $extra
                        ORDER BY page_random";
 
                $sql = $dbr->limitResult( $sql, 1, 0 );
                $res = $dbr->query( $sql, $fname );
                return $dbr->fetchObject( $res );
        }
-
-       private function getMaxPageRandom () {
-               $fname = 'RandomPage::getMaxPageRandom';
-
-               $dbr = wfGetDB( DB_SLAVE );
-
-               $from = $this->getSQLFrom( $dbr );
-               $where = $this->getSQLWhere( $dbr );
-
-               $sql = "SELECT MAX(page_random) AS max FROM $from WHERE $where";
-
-               $sql = $dbr->limitResult( $sql, 1, 0 );
-               $res = $dbr->query( $sql, $fname );
-               $row = $dbr->fetchObject( $res );
-
-               return $row ? $row->max : 0;
-       }
-
-       private function getSQLFrom ( $dbr ) {
-               $use_index = $dbr->useIndexClause( 'page_random' );
-               $page = $dbr->tableName( 'page' );
-               return "$page $use_index";
-       }
-
-       private function getSQLWhere ( $dbr ) {
-               global $wgExtraRandompageSQL;
-               $ns = (int) $this->namespace;
-               $redirect = $this->redirect ? 1 : 0;
-               $extra = $wgExtraRandompageSQL ? " AND ($wgExtraRandompageSQL)" : "";
-               return "page_namespace = $ns AND page_is_redirect = $redirect" . $extra;
-       }
 }
-
-?>