diff --git a/js/src/xpconnect/src/nsXPConnect.cpp b/js/src/xpconnect/src/nsXPConnect.cpp
index e2232c6cff3..076a473b123 100644
--- a/js/src/xpconnect/src/nsXPConnect.cpp
+++ b/js/src/xpconnect/src/nsXPConnect.cpp
@@ -42,11 +42,40 @@
 #define JS_CLASS_MAP_SIZE       256
 #define NATIVE_CLASS_MAP_SIZE   256
 
+#if 0
+extern "C" {
+  void __log_addref(void* p, int oldrc, int newrc);
+  void __log_release(void* p, int oldrc, int newrc);
+};
+
+NS_IMETHODIMP_(nsrefcnt) nsXPConnect::AddRef(void)
+{
+  NS_PRECONDITION(PRInt32(mRefCnt) >= 0, "illegal refcnt");
+  __log_addref(this, mRefCnt, mRefCnt + 1);
+  ++mRefCnt;
+  return mRefCnt;
+}
+
+NS_IMETHODIMP_(nsrefcnt) nsXPConnect::Release(void)
+{
+  NS_PRECONDITION(0 != mRefCnt, "dup release");
+  __log_release(this, mRefCnt, mRefCnt - 1);
+  --mRefCnt;
+  if (mRefCnt == 0) {
+    NS_DELETEXPCOM(this);
+    return 0;
+  }
+  return mRefCnt;
+}
+
+NS_IMPL_QUERY_INTERFACE1(nsXPConnect, nsIXPConnect)
+#else
 NS_IMPL_ISUPPORTS1(nsXPConnect, nsIXPConnect)
+#endif
 
 const char XPC_COMPONENTS_STR[] = "Components";
 
-nsXPConnect* nsXPConnect::mSelf = nsnull;
+nsXPConnect* nsXPConnect::gSelf = nsnull;
 
 /***************************************************************************/
 
@@ -141,21 +170,47 @@ GetPerThreadData()
 nsXPConnect*
 nsXPConnect::GetXPConnect()
 {
-    // XXX This pattern causes us to retain an extra ref on the singleton.
-    // XXX Should the singleton nsXPConnect object *ever* be deleted?
-    if(!mSelf)
+    if(!gSelf)
     {
-        mSelf = new nsXPConnect();
-        if(mSelf && (!mSelf->mContextMap ||
-                     !mSelf->mArbitraryScriptable ||
-                     !mSelf->mInterfaceInfoManager ||
-                     !mSelf->mThrower ||
-                     !mSelf->mContextStack))
-            NS_RELEASE(mSelf);
+        gSelf = new nsXPConnect();
+        if (!gSelf) {
+            return nsnull;
+        }
+        if (!gSelf->mContextMap ||
+            !gSelf->mArbitraryScriptable ||
+            !gSelf->mInterfaceInfoManager ||
+            !gSelf->mThrower ||
+            !gSelf->mContextStack)
+        {
+            // ctor failed to create an acceptable instance
+            delete gSelf;
+        }
+        else
+        {
+            // Keep the singleton alive
+            NS_ADDREF(gSelf);
+        }
+    }
+    if(gSelf)
+    {
+        NS_ADDREF(gSelf);
+    }
+    return gSelf;
+}
+
+void
+nsXPConnect::FreeXPConnect()
+{
+    nsXPConnect* xpc = gSelf;
+    if (xpc) {
+        nsrefcnt cnt;
+        NS_RELEASE2(xpc, cnt);
+#ifdef DEBUG_kipp
+        if (0 != cnt) {
+            printf("*** dangling reference to nsXPConnect: refcnt=%d\n", cnt);
+        }
+#endif
     }
-    if(mSelf)
-        NS_ADDREF(mSelf);
-    return mSelf;
 }
 
 // static
@@ -260,7 +315,6 @@ nsXPConnect::nsXPConnect()
         mContextStack(nsnull)
 {
     NS_INIT_REFCNT();
-    NS_ADDREF_THIS();
 
     nsXPCWrappedNativeClass::OneTimeInit();
     mContextMap = JSContext2XPCContextMap::newMap(CONTEXT_MAP_SIZE);
@@ -288,7 +342,7 @@ nsXPConnect::~nsXPConnect()
         delete mThrower;
     if(mContextStack)
         nsServiceManager::ReleaseService("nsThreadJSContextStack", mContextStack);
-    mSelf = nsnull;
+    gSelf = nsnull;
 }
 
 NS_IMETHODIMP
diff --git a/js/src/xpconnect/src/xpcmodule.cpp b/js/src/xpconnect/src/xpcmodule.cpp
index 8b26a9d215a..c553afae497 100644
--- a/js/src/xpconnect/src/xpcmodule.cpp
+++ b/js/src/xpconnect/src/xpcmodule.cpp
@@ -34,12 +34,12 @@
 
 /* Module level methods. */
 
+#include "nsCOMPtr.h"
 #include "xpcprivate.h"
+#include "nsIModule.h"
 
 /***************************************************************************/
 
-static NS_DEFINE_CID(kComponentManagerCID, NS_COMPONENTMANAGER_CID);
-static NS_DEFINE_CID(kGenericFactoryCID, NS_GENERICFACTORY_CID);
 static NS_DEFINE_CID(kJSID_CID,  NS_JS_ID_CID);
 static NS_DEFINE_CID(kXPCException_CID,  NS_XPCEXCEPTION_CID);
 static NS_DEFINE_CID(kXPConnect_CID, NS_XPCONNECT_CID);
@@ -142,113 +142,262 @@ Construct_nsJSRuntimeService(nsISupports *aOuter, REFNSIID aIID, void **aResult)
 
 /********************************************/
 
-extern "C" PR_IMPLEMENT(nsresult)
-NSGetFactory(nsISupports* aServMgr,
-             const nsCID &aClass,
-             const char *aClassName,
-             const char *aProgID,
-             nsIFactory **aFactory)
+// Module implementation for the xpconnect library
+
+class nsXPConnectModule : public nsIModule
 {
-    nsresult rv;
-    NS_ASSERTION(aFactory != nsnull, "bad factory pointer");
+public:
+    nsXPConnectModule();
+    virtual ~nsXPConnectModule();
 
-    NS_WITH_SERVICE1(nsIComponentManager, compMgr,
-                     aServMgr, kComponentManagerCID, &rv);
-    if (NS_FAILED(rv)) return rv;
+    NS_DECL_ISUPPORTS
 
-    nsIGenericFactory* factory;
-    rv = compMgr->CreateInstance(kGenericFactoryCID, nsnull,
-                                 nsIGenericFactory::GetIID(),
-                                 (void**)&factory);
-    if (NS_FAILED(rv)) return rv;
+    NS_DECL_NSIMODULE
 
-    // add more factories as 'if else's below...
+protected:
+    nsresult Initialize();
 
-    if(aClass.Equals(kJSID_CID))
-        rv = factory->SetConstructor(nsJSIDConstructor);
-    else if(aClass.Equals(kXPConnect_CID))
-        rv = factory->SetConstructor(Construct_nsXPConnect);
-    else if(aClass.Equals(kXPCThreadJSContextStack_CID))
-        rv = factory->SetConstructor(Construct_nsXPCThreadJSContextStack);
-    else if(aClass.Equals(kXPCException_CID))
-        rv = factory->SetConstructor(nsXPCExceptionConstructor);
-    else if(aClass.Equals(kJSRuntime_CID))
-        rv = factory->SetConstructor(Construct_nsJSRuntimeService);
-    else
-    {
-        NS_ASSERTION(0, "incorrectly registered");
-        rv = NS_ERROR_NO_INTERFACE;
+    void Shutdown();
+
+    PRBool mInitialized;
+    nsCOMPtr<nsIGenericFactory> mJSIDFactory;
+    nsCOMPtr<nsIGenericFactory> mXPConnectFactory;
+    nsCOMPtr<nsIGenericFactory> mXPCThreadJSContextStackFactory;
+    nsCOMPtr<nsIGenericFactory> mXPCExceptionFactory;
+    nsCOMPtr<nsIGenericFactory> mJSRuntimeServiceFactory;
+};
+
+static NS_DEFINE_IID(kIModuleIID, NS_IMODULE_IID);
+
+nsXPConnectModule::nsXPConnectModule()
+    : mInitialized(PR_FALSE)
+{
+    NS_INIT_ISUPPORTS();
+}
+
+nsXPConnectModule::~nsXPConnectModule()
+{
+    Shutdown();
+}
+
+NS_IMPL_ISUPPORTS(nsXPConnectModule, kIModuleIID)
+
+// Perform our one-time intialization for this module
+nsresult
+nsXPConnectModule::Initialize()
+{
+    if (mInitialized) {
+        return NS_OK;
     }
-
-    if (NS_FAILED(rv)) {
-        NS_RELEASE(factory);
-        return rv;
-    }
-    *aFactory = factory;
+    mInitialized = PR_TRUE;
     return NS_OK;
 }
 
-/***************************************************************************/
-
-extern "C" XPC_PUBLIC_API(PRBool)
-NSCanUnload(nsISupports* aServMgr)
+// Shutdown this module, releasing all of the module resources
+void
+nsXPConnectModule::Shutdown()
 {
-  return PR_FALSE;
+    // Release the factory objects
+    mJSIDFactory = nsnull;
+    mXPConnectFactory = nsnull;
+    mXPCThreadJSContextStackFactory = nsnull;
+    mXPCExceptionFactory = nsnull;
+    mJSRuntimeServiceFactory = nsnull;
+
+    // Release our singletons
+    nsXPCThreadJSContextStackImpl::FreeSingleton();
+    nsJSRuntimeServiceImpl::FreeSingleton();
+    nsXPConnect::FreeXPConnect();
 }
 
-extern "C" XPC_PUBLIC_API(nsresult)
-NSRegisterSelf(nsISupports* aServMgr, const char *aPath)
+// Create a factory object for creating instances of aClass.
+NS_IMETHODIMP
+nsXPConnectModule::GetClassObject(nsIComponentManager *aCompMgr,
+                                  const nsCID& aClass,
+                                  const nsIID& aIID,
+                                  void** r_classObj)
 {
     nsresult rv;
+
+    // Defensive programming: Initialize *r_classObj in case of error below
+    if (!r_classObj) {
+        return NS_ERROR_INVALID_POINTER;
+    }
+    *r_classObj = NULL;
+
+    // Do one-time-only initialization if necessary
+    if (!mInitialized) {
+        rv = Initialize();
+        if (NS_FAILED(rv)) {
+            // Initialization failed! yikes!
+            return rv;
+        }
+    }
+
+    // Choose the appropriate factory, based on the desired instance
+    // class type (aClass).
+    nsCOMPtr<nsIGenericFactory> fact;
+    if (aClass.Equals(kJSID_CID)) {
+        if (!mJSIDFactory.get()) {
+            rv = NS_NewGenericFactory(getter_AddRefs(mJSIDFactory),
+                                      nsJSIDConstructor);
+        }
+        fact = mJSIDFactory;
+    } else if(aClass.Equals(kXPConnect_CID)) {
+        if (!mXPConnectFactory.get()) {
+            rv = NS_NewGenericFactory(getter_AddRefs(mXPConnectFactory),
+                                      Construct_nsXPConnect);
+        }
+        fact = mXPConnectFactory;
+    } else if(aClass.Equals(kXPCThreadJSContextStack_CID)) {
+        if (!mXPCThreadJSContextStackFactory.get()) {
+            rv = NS_NewGenericFactory(getter_AddRefs(mXPCThreadJSContextStackFactory),
+                                      Construct_nsXPCThreadJSContextStack);
+        }
+        fact = mXPCThreadJSContextStackFactory;
+    } else if(aClass.Equals(kXPCException_CID)) {
+        if (!mXPCExceptionFactory.get()) {
+            rv = NS_NewGenericFactory(getter_AddRefs(mXPCExceptionFactory),
+                                      nsXPCExceptionConstructor);
+        }
+        fact = mXPCExceptionFactory;
+    } else if(aClass.Equals(kJSRuntime_CID)) {
+        if (!mJSRuntimeServiceFactory.get()) {
+            rv = NS_NewGenericFactory(getter_AddRefs(mJSRuntimeServiceFactory),
+                                      Construct_nsJSRuntimeService);
+        }
+        fact = mJSRuntimeServiceFactory;
+    }
+    else {
+        rv = NS_ERROR_FACTORY_NOT_REGISTERED;
 #ifdef DEBUG
-    printf("*** Register XPConnect\n");
+        char* cs = aClass.ToString();
+        printf("+++ nsXPConnectModule: unable to create factory for %s\n", cs);
+        nsCRT::free(cs);
 #endif
-    NS_WITH_SERVICE1(nsIComponentManager, compMgr,
-                     aServMgr, kComponentManagerCID, &rv);
-    if (NS_FAILED(rv)) return rv;
+    }
 
-    rv = compMgr->RegisterComponent(kJSID_CID,
-                                    "nsIJSID","nsID",
-                                    aPath, PR_TRUE, PR_TRUE);
-    if (NS_FAILED(rv)) return rv;
+    if (fact) {
+        rv = fact->QueryInterface(aIID, r_classObj);
+    }
 
-    rv = compMgr->RegisterComponent(kXPConnect_CID,
-                                    "nsIXPConnect","nsIXPConnect",
-                                    aPath, PR_TRUE, PR_TRUE);
-    if (NS_FAILED(rv)) return rv;
-
-    rv = compMgr->RegisterComponent(kXPCThreadJSContextStack_CID,
-                                    "nsThreadJSContextStack","nsThreadJSContextStack",
-                                    aPath, PR_TRUE, PR_TRUE);
-    if (NS_FAILED(rv)) return rv;
-
-    rv = compMgr->RegisterComponent(kXPCException_CID,
-                                    "nsXPCException","nsXPCException",
-                                    aPath, PR_TRUE, PR_TRUE);
-    if (NS_FAILED(rv)) return rv;
-
-    rv = compMgr->RegisterComponent(kJSRuntime_CID,
-                                    "JS Runtime Service", "nsJSRuntimeService",
-                                    aPath, PR_TRUE, PR_TRUE);
     return rv;
 }
 
-extern "C" XPC_PUBLIC_API(nsresult)
-NSUnregisterSelf(nsISupports* aServMgr, const char *aPath)
-{
-    nsresult rv;
-#ifdef DEBUG
-    printf("*** Unregister XPConnect\n");
-#endif
-    NS_WITH_SERVICE1(nsIComponentManager, compMgr,
-                     aServMgr, kComponentManagerCID, &rv);
-    if (NS_FAILED(rv)) return rv;
+//----------------------------------------
 
-    rv = compMgr->UnregisterComponent(kJSID_CID, aPath);
-    rv = compMgr->UnregisterComponent(kXPConnect_CID, aPath);
-    rv = compMgr->UnregisterComponent(kXPCThreadJSContextStack_CID, aPath);
-    rv = compMgr->UnregisterComponent(kXPCException_CID, aPath);
-    rv = compMgr->UnregisterComponent(kJSRuntime_CID, aPath);
+struct Components {
+    const char* mDescription;
+    const nsID* mCID;
+    const char* mProgID;
+};
+
+// The list of components we register
+// XXX These progids look pretty bogus!
+static Components gComponents[] = {
+    { "nsIJSID", &kJSID_CID,
+      "nsID", },
+    { "nsIXPConnect", &kXPConnect_CID,
+      "nsIXPConnect", },
+    { "nsThreadJSContextStack", &kXPCThreadJSContextStack_CID,
+      "nsThreadJSContextStack", },
+    { "nsXPCException", &kXPCException_CID,
+      "nsXPCException", },
+    { "JS Runtime Service", &kJSRuntime_CID,
+      "nsJSRuntimeService", },
+};
+#define NUM_COMPONENTS (sizeof(gComponents) / sizeof(gComponents[0]))
+
+NS_IMETHODIMP
+nsXPConnectModule::RegisterSelf(nsIComponentManager *aCompMgr,
+                                nsIFileSpec* aPath,
+                                const char* registryLocation,
+                                const char* componentType)
+{
+    nsresult rv = NS_OK;
+
+#ifdef DEBUG
+    printf("*** Registering xpconnect components\n");
+#endif
+
+    Components* cp = gComponents;
+    Components* end = cp + NUM_COMPONENTS;
+    while (cp < end) {
+        rv = aCompMgr->RegisterComponentSpec(*cp->mCID, cp->mDescription,
+                                             cp->mProgID, aPath, PR_TRUE,
+                                             PR_TRUE);
+        if (NS_FAILED(rv)) {
+#ifdef DEBUG
+            printf("nsXPConnectModule: unable to register %s component => %x\n",
+                   cp->mDescription, rv);
+#endif
+            break;
+        }
+        cp++;
+    }
 
     return rv;
 }
+
+NS_IMETHODIMP
+nsXPConnectModule::UnregisterSelf(nsIComponentManager* aCompMgr,
+                                  nsIFileSpec* aPath,
+                                  const char* registryLocation)
+{
+#ifdef DEBUG
+    printf("*** Unregistering xpconnect components\n");
+#endif
+    Components* cp = gComponents;
+    Components* end = cp + NUM_COMPONENTS;
+    while (cp < end) {
+        nsresult rv = aCompMgr->UnregisterComponentSpec(*cp->mCID, aPath);
+        if (NS_FAILED(rv)) {
+#ifdef DEBUG
+            printf("nsXPConnectModule: unable to unregister %s component => %x\n",
+                   cp->mDescription, rv);
+#endif
+        }
+        cp++;
+    }
+
+    return NS_OK;
+}
+
+NS_IMETHODIMP
+nsXPConnectModule::CanUnload(nsIComponentManager *aCompMgr, PRBool *okToUnload)
+{
+    if (!okToUnload) {
+        return NS_ERROR_INVALID_POINTER;
+    }
+    *okToUnload = PR_FALSE;
+    return NS_ERROR_FAILURE;
+}
+
+//----------------------------------------------------------------------
+
+static nsXPConnectModule *gModule = NULL;
+
+extern "C" NS_EXPORT nsresult NSGetModule(nsIComponentManager *servMgr,
+                                          nsIFileSpec* location,
+                                          nsIModule** return_cobj)
+{
+    nsresult rv = NS_OK;
+
+    NS_ASSERTION(return_cobj, "Null argument");
+    NS_ASSERTION(gModule == NULL, "nsXPConnectModule: Module already created.");
+
+    // Create an initialize the layout module instance
+    nsXPConnectModule *m = new nsXPConnectModule();
+    if (!m) {
+        return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    // Increase refcnt and store away nsIModule interface to m in return_cobj
+    rv = m->QueryInterface(NS_GET_IID(nsIModule), (void**)return_cobj);
+    if (NS_FAILED(rv)) {
+        delete m;
+        m = nsnull;
+    }
+    gModule = m;                  // WARNING: Weak Reference
+    return rv;
+}
diff --git a/js/src/xpconnect/src/xpcprivate.h b/js/src/xpconnect/src/xpcprivate.h
index 49bcf41a667..c888e71dac0 100644
--- a/js/src/xpconnect/src/xpcprivate.h
+++ b/js/src/xpconnect/src/xpcprivate.h
@@ -160,6 +160,7 @@ class nsXPConnect : public nsIXPConnect
     // non-interface implementation
 public:
     static nsXPConnect* GetXPConnect();
+    static void FreeXPConnect();
     static nsIInterfaceInfoManager* GetInterfaceInfoManager(nsXPConnect* xpc = nsnull);
     static XPCContext*  GetContext(JSContext* cx, nsXPConnect* xpc = nsnull);
     static XPCJSThrower* GetJSThrower(nsXPConnect* xpc = nsnull);
@@ -176,7 +177,9 @@ private:
                             JSBool doInit = JS_TRUE);
 
 private:
-    static nsXPConnect* mSelf;
+    // Singleton instance
+    static nsXPConnect* gSelf;
+
     JSContext2XPCContextMap* mContextMap;
     nsIXPCScriptable* mArbitraryScriptable;
     nsIInterfaceInfoManager* mInterfaceInfoManager;
@@ -963,6 +966,7 @@ public:
     NS_DECL_NSIJSCONTEXTSTACK
 
     static nsXPCThreadJSContextStackImpl* GetSingleton();
+    static void FreeSingleton();
 
     nsXPCThreadJSContextStackImpl();
     virtual ~nsXPCThreadJSContextStackImpl();
@@ -1005,6 +1009,7 @@ class nsJSRuntimeServiceImpl : public nsIJSRuntimeService
     NS_DECL_NSIJSRUNTIMESERVICE
         
     static nsJSRuntimeServiceImpl *GetSingleton();
+    static void FreeSingleton();
 
     nsJSRuntimeServiceImpl();
     virtual ~nsJSRuntimeServiceImpl();
diff --git a/js/src/xpconnect/src/xpcruntimesvc.cpp b/js/src/xpconnect/src/xpcruntimesvc.cpp
index 4f1d018364d..95e3685f894 100644
--- a/js/src/xpconnect/src/xpcruntimesvc.cpp
+++ b/js/src/xpconnect/src/xpcruntimesvc.cpp
@@ -30,7 +30,6 @@ nsJSRuntimeServiceImpl::nsJSRuntimeServiceImpl() :
     mRuntime(0)
 {
     NS_INIT_ISUPPORTS();
-    NS_ADDREF_THIS();
 }
 
 nsJSRuntimeServiceImpl::~nsJSRuntimeServiceImpl() {
@@ -43,16 +42,25 @@ nsJSRuntimeServiceImpl::~nsJSRuntimeServiceImpl() {
 
 NS_IMPL_ISUPPORTS1(nsJSRuntimeServiceImpl, nsIJSRuntimeService);
 
+static nsJSRuntimeServiceImpl* gJSRuntimeService = nsnull;
+
 nsJSRuntimeServiceImpl*
 nsJSRuntimeServiceImpl::GetSingleton()
 {
-    static nsJSRuntimeServiceImpl *singleton = nsnull;
-    if (!singleton) {
-	if ((singleton = new nsJSRuntimeServiceImpl()) != nsnull)
-	    NS_ADDREF(singleton);
+    if (!gJSRuntimeService) {
+	gJSRuntimeService = new nsJSRuntimeServiceImpl();
+        if (gJSRuntimeService) {
+	    NS_ADDREF(gJSRuntimeService);
+        }
     }
-    NS_IF_ADDREF(singleton);
-    return singleton;
+    NS_IF_ADDREF(gJSRuntimeService);
+    return gJSRuntimeService;
+}
+
+void
+nsJSRuntimeServiceImpl::FreeSingleton()
+{
+    NS_IF_RELEASE(gJSRuntimeService);
 }
 
 const uint32 gGCSize = 4L * 1024L * 1024L; /* pref? */
diff --git a/js/src/xpconnect/src/xpcthreadcontext.cpp b/js/src/xpconnect/src/xpcthreadcontext.cpp
index 0fe41e735f3..b488a9ddc8a 100644
--- a/js/src/xpconnect/src/xpcthreadcontext.cpp
+++ b/js/src/xpconnect/src/xpcthreadcontext.cpp
@@ -100,18 +100,25 @@ nsXPCThreadJSContextStackImpl::~nsXPCThreadJSContextStackImpl() {}
 
 NS_IMPL_ISUPPORTS1(nsXPCThreadJSContextStackImpl, nsIJSContextStack)
 
+static nsXPCThreadJSContextStackImpl* gXPCThreadJSContextStack = nsnull;
+
 //static
 nsXPCThreadJSContextStackImpl*
 nsXPCThreadJSContextStackImpl::GetSingleton()
 {
-    static nsXPCThreadJSContextStackImpl* singleton = nsnull;
-    if(!singleton)
+    if(!gXPCThreadJSContextStack)
     {
-        if(nsnull != (singleton = new nsXPCThreadJSContextStackImpl()))
-            NS_ADDREF(singleton);
+        if(nsnull != (gXPCThreadJSContextStack = new nsXPCThreadJSContextStackImpl()))
+            NS_ADDREF(gXPCThreadJSContextStack);
     }
-    NS_IF_ADDREF(singleton);
-    return singleton;
+    NS_IF_ADDREF(gXPCThreadJSContextStack);
+    return gXPCThreadJSContextStack;
+}
+
+void
+nsXPCThreadJSContextStackImpl::FreeSingleton()
+{
+    NS_IF_RELEASE(gXPCThreadJSContextStack);
 }
 
 /* readonly attribute PRInt32 Count; */