Extension:BreadCrumbs (Kimon)

<?php
 
# The BreadCrumbs extension, an extension for providing an breadcrumbs
# navigation to users.
 
# @addtogroup Extensions
# @author Manuel Schneider <manuel.schneider@wikimedia.ch>
# @author Kimon Andreou
# @copyright © 2007 by Manuel Schneider, Kimon Andreou
# @licence GNU General Public Licence 2.0 or later
 
 
if( !defined( 'MEDIAWIKI' ) ) {
  echo( "This file is an extension to the MediaWiki software and cannot be used standalone.\n" );
  die();
}
 
## Options:
# set the delimiter
$wgBreadCrumbsDelimiter = ' &gt; ';
# number of breadcrumbs to use
$wgBreadCrumbsCount = 5;
 
$bcBreadCrumbs = new BreadCrumbs();
 
$wgExtensionFunctions[] = array($bcBreadCrumbs, 'setup');
$wgHooks['UserToggles'][] = array($bcBreadCrumbs, 'toggle');
 
$wgExtensionCredits['parserhook'][] = array(
  'name'          => 'BreadCrumbs',
  'author'        => 'Kimon Andreou',
  'url'           => 'http://www.mediawiki.org/wiki/Extension:BreadCrumbs_(Kimon)',
  'description'   => "Shows a breadcrumb navigation. Based heavily on Manuel Shneider's extension[http://www.mediawiki.org/wiki/Extension:BreadCrumbs]"
);
 
##
## Main class
class BreadCrumbs {
  #constructor
  function BreadCrumbs() {}
 
  ## Set Hook:
  function setup() {
    global $wgUser, $wgHooks;
 
    #can we see the breadcrumbs?
    if($wgUser->getOption('breadcrumb')==0) {
      return;
    }
 
    ## Showing and updating the breadcrumbs trail
    # Hook when viewing article header:
    $wgHooks['ArticleViewHeader'][] = array($this, 'show');
 
  ## Infrastructure
  # Hook our own CSS:
  $wgHooks['OutputPageParserOutput'][] = array($this, 'output');
  }
 
  #Return our new user preference (t/f toggle)
  function toggle(&$arr) {
    global $wgMessageCache;
    #named "breadcrumb" - original, no?
    $arr[] = 'breadcrumb';
    $wgMessageCache->addMessage('tog-breadcrumb', 'Use breadcrumbs');
    return true;
  }
 
  #Show the breadcrumbs on the page
  function show( &$m_pageObj ) {
    global $wgUser, $wgTitle, $wgOut, $wgBreadCrumbsDelimiter, $wgBreadCrumbsCount;
 
    # deserialize data from session into array:
    $m_BreadCrumbs = array();
 
    #If a session doesn't already exist, create one
    if( isset( $_SESSION['BreadCrumbs'] ) ) {
      $m_BreadCrumbs = $_SESSION['BreadCrumbs'];
    }
    else {
      if( !isset( $_SESSION ) ) {
        session_start();
      }
      $_SESSION['BreadCrumbs'] = array();
    }
    # cache index of last element:
    $m_count = count( $m_BreadCrumbs ) - 1;
 
    # if we've got too many entries, reduce the array:
    if( count( $m_BreadCrumbs ) > 0 && $m_BreadCrumbs[ $m_count ] != $wgTitle->getPrefixedText() ) {
      # reduce the array set, remove older elements:
      $m_BreadCrumbs = array_slice( $m_BreadCrumbs, ( 1 - $wgBreadCrumbsCount ) );
      # add new page:
      array_push( $m_BreadCrumbs, $wgTitle->getPrefixedText() );
    }
    else {
      array_push( $m_BreadCrumbs, $wgTitle->getPrefixedText() );
    }
 
    #if returning to a page we've already visited, reduce the array
    $loc = array_search($wgTitle->getPrefixedText(), $m_BreadCrumbs);
    if(($loc >= 0)) {
      #shrink array
      $m_BreadCrumbs = array_slice($m_BreadCrumbs, 0, ($loc + 1));
    } 
 
    # serialize data from array to session:
    $_SESSION['BreadCrumbs'] = $m_BreadCrumbs;
    # update cache:
    $m_count = count( $m_BreadCrumbs ) - 1;
 
    # acquire a skin object:
    $m_skin =& $wgUser->getSkin();
    # build the breadcrumbs trail:
    $m_trail = "<div id=\"BreadCrumbsTrail\">&nbsp;<i>Bread crumbs:</i> ";
    for( $i = 0; $i <= $m_count; $i++ ) {
      $m_trail .= $m_skin->makeLink( $m_BreadCrumbs[$i] );
      if( $i < $m_count ) $m_trail .= $wgBreadCrumbsDelimiter;
    }
    $m_trail .= '&nbsp;</div>';
    $wgOut->addHTML( $m_trail );
 
    # invalidate internal MediaWiki cache:
    $wgTitle->invalidateCache();
    $wgUser->invalidateCache();
 
    # Return true to let the rest work:
    return true;
  }
 
  ## Entry point for the hook for printing the CSS:
  # todo: find a better implementation
  function output( &$m_pageObj, &$m_parserOutput ) {
    global $wgScriptPath;
 
    # Register CSS file for our select box:
    $m_pageObj->addLink(
      array(
        'rel'   => 'stylesheet',
        'type'  => 'text/css',
        'href'  => $wgScriptPath . '/extensions/BreadCrumbs/BreadCrumbs.css'
      )
    );
 
    # Be nice:
    return true;
  }
}
 
?>

/* Stylesheet for the BreadCrumbs extension, an extension of the
 * edit box of MediaWiki to provide an easy way to add category links
 * to a specific page.
 *
 * @package MediaWiki
 * @subpackage Extensions
 * @author Manuel Schneider <manuel.schneider@wikimedia.ch>
 * @author Kimon Andreou
 * @copyright © 2007 by Manuel Schneider
 * @licence GNU General Public Licence 2.0 or later
*/
 
#BreadCrumbsTrail {
        font-size:0.8em;
        background-color: #FFFFCC;
        position:absolute;
        left: 2px;
        bottom:0;
        width:99%;
}

require_once( "$IP/extensions/BreadCrumbs/BreadCrumbs.php" );