More Sanitizer Refactoring

Make the Sanitizer more efficient.
Also, update some unit tests.

lib/sanitizer.rb

@@ -123,16 +123,16 @@ module Sanitizer
       #
       #   xhtml_sanitize('<script> do_nasty_stuff() </script>')
       #    => &lt;script> do_nasty_stuff() &lt;/script>
-      #   xhtml_sanitize_xhtml('<a href="javascript: sucker();">Click here for $100</a>')
+      #   xhtml_sanitize('<a href="javascript: sucker();">Click here for $100</a>')
       #    => <a>Click here for $100</a>
       def xhtml_sanitize(html)
-        if html.index("<")
+        return html unless sanitizeable?(html)
         tokenizer = HTML::Tokenizer.new(html.to_utf8)
-          new_text = ""
+        results = []
 
         while token = tokenizer.next
           node = XHTML::Node.parse(nil, 0, 0, token, false)
-            new_text << case node.tag?
+          results << case node.tag?
             when true
               if ALLOWED_ELEMENTS.include?(node.name)
                 process_attributes_for(node)
@@ -145,9 +145,11 @@ module Sanitizer
           end
         end
 
-          html = new_text
+        results.join
       end
-        html
+
+      def sanitizeable?(text)
+        !(text.nil? || text.empty? || !text.index("<"))
       end
 
   protected

test/unit/page_renderer_test.rb

@@ -373,10 +373,10 @@ END_THM
     assert_markup_parsed_as(
         "<p>should we go <a class='existingWikiWord' href='../show/ThatWay'>" +
 	    "That Way</a> or</p>\n<div class='maruku-equation' id='eq:eq1'>" +
-	    "<math class='maruku-mathml' display='block' " +
+	    "<span class='maruku-eq-number'>(1)</span><math class='maruku-mathml' display='block' " +
 	    "xmlns='http://www.w3.org/1998/Math/MathML'><mi>ThisWay</mi></math>" +
 	    "<span class='maruku-eq-tex'><code style='display: none;'>ThisWay</code>" +
-	    "</span><span class='maruku-eq-number'>(1)</span></div>", 
+	    "</span></div>", 
         "should we go ThatWay or \n\\[ThisWay\\]\n")
 
     assert_markup_parsed_as(