Switch to a different strategy for event handler garbage collection. …

…Store references to elements instead of searching the entire document. [#10 state:resolved]

CHANGELOG

@@ -1,3 +1,5 @@
+* Switch to a different strategy for event handler garbage collection. Store references to elements instead of searching the entire document. (jddalton, kangax, Andrew Dupont)
+
 * Add event cleanup on Element#update and Element#replace so that replaced content does not leak memory. (jddalton, Andrew Dupont)
 
 * Loop through all elements and remove all handlers on page unload. IE needs this in order to prevent memory leaks. (kangax, jddalton, Andrew Dupont)

src/dom.js

@@ -878,23 +878,11 @@ else if (Prototype.Browser.IE) {
     });
   })(Element._attributeTranslations.read.values);
 
-  // Wrap Element#update and Element#replace to clean up event handlers on 
+  // Wrap Element#update to clean up event handlers on 
   // newly-removed elements. Prevents memory leaks in IE.  
-  Element._purgeObservers = function(element, includeRoot) {
-    Element.select(element, '*').each(Event.stopObserving);
-    if (includeRoot === true) Event.stopObserving(element);
-  };
-
   Element.Methods.update = Element.Methods.update.wrap(
     function(proceed, element, contents) {
-      Element._purgeObservers(element, false);
-      return proceed(element, contents);
-    }
-  );
-
-  Element.Methods.replace = Element.Methods.replace.wrap(
-    function(proceed, element, contents) {
-      Element._purgeObservers(element, true);
+      Element.select(element, '*').each(Event.stopObserving);
       return proceed(element, contents);
     }
   );  

src/event.js

@@ -148,8 +148,11 @@ Object.extend(Event, (function() {
   var cache = Event.cache;
 
   function getEventID(element) {
+    // Event ID is stored as the 0th index in a one-item array so that it
+    // won't get copied to a new node when cloneNode is called.
     if (element._prototypeEventID) return element._prototypeEventID[0];
     arguments.callee.id = arguments.callee.id || 1;
+
     return element._prototypeEventID = [++arguments.callee.id];
   }
 
@@ -168,7 +171,12 @@ Object.extend(Event, (function() {
   }
 
   function createWrapper(element, eventName, handler) {
-    var id = getEventID(element);
+    var id = getEventID(element), _c = getCacheForID(id);
+
+    // Attach the element itself onto its cache entry so we can retrieve it for
+    // cleanup on page unload.
+    if (!_c.element) _c.element = element;
+
     var c = getWrappersForEventName(id, eventName);
     if (c.pluck("handler").include(handler)) return false;
 
@@ -200,16 +208,17 @@ Object.extend(Event, (function() {
   // Loop through all elements and remove all handlers on page unload. IE
   // needs this in order to prevent memory leaks.
   function purgeListeners() {
-    var all = document.getElementsByTagName('*');    
-    for (var i, node; node = all[i]; i++) {
-      if (node.nodeType !== Node.ELEMENT_NODE) continue;
-      Element.stopObserving(node);
+    var element, entry;
+    for (var i in Event.cache) {
+      entry = Event.cache[i];
+      Event.stopObserving(entry.element);
+      entry.element = null;
     }
   }
 
   function onStop() {
     document.detachEvent('onstop', onStop);
-    destroyCache();
+    purgeListeners();
   }
 
   function onBeforeUnload() {