--- a/object.c	Sun Jun 28 20:40:18 2009 -0700
+++ b/object.c	Sun Jun 28 21:49:07 2009 -0700
@@ -1,5 +1,6 @@
 #include "object.h"
 #include "runtime.h"
+#include "utils.h"
 
 JSClass PYM_JS_ObjectClass = {
   "PymonkeyObject", JSCLASS_GLOBAL_FLAGS,
@@ -11,16 +12,26 @@
 static void
 PYM_JSObjectDealloc(PYM_JSObject *self)
 {
-  // JS_RemoveRoot() always returns JS_TRUE, so don't
-  // bother checking its return value.
+  if (self->weakrefList)
+    PyObject_ClearWeakRefs((PyObject *) self);
 
   if (self->obj) {
+    if (PyDict_DelItem(self->runtime->objects,
+                       self->uniqueId) == -1)
+      PySys_WriteStderr("WARNING: PyDict_DelItem() failed.\n");
+    Py_DECREF(self->uniqueId);
+    self->uniqueId = NULL;
+
+    // JS_RemoveRoot() always returns JS_TRUE, so don't
+    // bother checking its return value.
     JS_RemoveRootRT(self->runtime->rt, &self->obj);
     self->obj = NULL;
   }
 
-  Py_DECREF(self->runtime);
-  self->runtime = NULL;
+  if (self->runtime) {
+    Py_DECREF(self->runtime);
+    self->runtime = NULL;
+  }
 }
 
 PyTypeObject PYM_JSObjectType = {
@@ -51,7 +62,8 @@
   0,		               /* tp_traverse */
   0,		               /* tp_clear */
   0,		               /* tp_richcompare */
-  0,		               /* tp_weaklistoffset */
+  /* tp_weaklistoffset */
+  offsetof(PYM_JSObject, weakrefList),
   0,		               /* tp_iter */
   0,		               /* tp_iternext */
   0,                           /* tp_methods */
@@ -69,15 +81,56 @@
 
 PYM_JSObject *PYM_newJSObject(PYM_JSContextObject *context,
                               JSObject *obj) {
+  jsid uniqueId;
+  if (!JS_GetObjectId(context->cx, obj, &uniqueId)) {
+    PyErr_SetString(PYM_error, "JS_GetObjectId() failed");
+    return NULL;
+  }
+  PyObject *pyUniqueId = PyLong_FromLong(uniqueId);
+  if (pyUniqueId == NULL)
+    return NULL;
+
+  PYM_JSRuntimeObject *runtime = context->runtime;
+  PyObject *cachedObject = PyDict_GetItem(runtime->objects,
+                                          pyUniqueId);
+  if (cachedObject) {
+    cachedObject = PyWeakref_GetObject(cachedObject);
+    Py_INCREF(cachedObject);
+    Py_DECREF(pyUniqueId);
+    return (PYM_JSObject *) cachedObject;
+  }
+
   PYM_JSObject *object = PyObject_New(PYM_JSObject,
                                       &PYM_JSObjectType);
-  if (object == NULL)
+  if (object == NULL) {
+    Py_DECREF(pyUniqueId);
     return NULL;
+  }
+
+  object->runtime = NULL;
+  object->obj = NULL;
+  object->uniqueId = NULL;
+  object->weakrefList = NULL;
+
+  PyObject *weakref = PyWeakref_NewRef((PyObject *) object, NULL);
+  if (weakref == NULL) {
+    Py_DECREF(object);
+    Py_DECREF(pyUniqueId);
+    return NULL;
+  }
+
+  if (PyDict_SetItem(runtime->objects, pyUniqueId, weakref) == -1) {
+    Py_DECREF(weakref);
+    Py_DECREF(object);
+    Py_DECREF(pyUniqueId);
+    return NULL;
+  }
 
   object->runtime = context->runtime;
   Py_INCREF(object->runtime);
 
   object->obj = obj;
+  object->uniqueId = pyUniqueId;
 
   JS_AddNamedRootRT(object->runtime->rt, &object->obj,
                     "Pymonkey-Generated Object");