Firefoxの拡張機能でブックマーク情報を参照する方法

Firefoxの拡張機能でブックマークされたURLを取得する方法。

function getBookmark()
{
  hbm = new Array();

  // The RDF service
  var rdf = Components.classes['@mozilla.org/rdf/rdf-service;1']
            .getService(Components.interfaces.nsIRDFService);
	
  // The RDF component utilities
  var rdfc = Components.classes['@mozilla.org/rdf/container-utils;1']
             .getService(Components.interfaces.nsIRDFContainerUtils);

  // The bookmarks service
  var Bookmarks = Components.classes['@mozilla.org/browser/bookmarks-service;1']
             .getService(Components.interfaces.nsIRDFDataSource);
  var kNC_BookmarksRoot = rdf.GetResource("NC:BookmarksRoot");
  var kNC_Name = rdf.GetResource("http://home.netscape.com/NC-rdf#Name");
  var kNC_URL  = rdf.GetResource("http://home.netscape.com/NC-rdf#URL");

  function getBookmarkRecursively(node)
  {
    if (rdfc.IsContainer(Bookmarks, node)) {
      // folder
      var folder = Bookmarks.GetTarget(node, kNC_Name, true);
      var name = folder.QueryInterface(Components.interfaces.nsIRDFLiteral).Value;
      var container = Components.classes['@mozilla.org/rdf/container;1']
                      .createInstance(Components.interfaces.nsIRDFContainer);
      container.Init(Bookmarks, node);

      var contents = container.GetElements();
      while (contents.hasMoreElements()) {
        var next = contents.getNext()
                   .QueryInterface(Components.interfaces.nsIRDFResource);
        getBookmarkRecursively(next);
      }
    }
    else {
      // bookmark
      try {
        var bm = Bookmarks.GetTarget(node, kNC_URL, true);
	var url = bm.QueryInterface(Components.interfaces.nsIRDFLiteral).Value
        hbm[url] = true;
      }
      catch (ex) {
      }
    }
  }

  getBookmarkRecursively(kNC_BookmarksRoot);

  return hbm;
}