Bug 635552 - Avoid leaking nsAlertsIconObserver objects by using a weak reference. r=karlt

toolkit/system/gnome/nsAlertsIconListener.cpp

@@ -75,32 +75,19 @@ static void notify_closed_marshal(GClosure* closure,
   NS_RELEASE(alert);
 }
 
-NS_IMPL_ISUPPORTS3(nsAlertsIconListener, imgIContainerObserver, imgIDecoderObserver, nsIObserver)
+NS_IMPL_ISUPPORTS4(nsAlertsIconListener, imgIContainerObserver,
+                   imgIDecoderObserver, nsIObserver, nsISupportsWeakReference)
 
 nsAlertsIconListener::nsAlertsIconListener()
 : mLoadedFrame(PR_FALSE),
-  mHasQuit(PR_FALSE),
   mNotification(NULL)
 {
-  MOZ_COUNT_CTOR(nsAlertsIconListener);
-
-  nsCOMPtr<nsIObserverService> obsServ =
-      do_GetService("@mozilla.org/observer-service;1");
-  obsServ->AddObserver(this, "quit-application", PR_FALSE);
 }
 
 nsAlertsIconListener::~nsAlertsIconListener()
 {
-  MOZ_COUNT_DTOR(nsAlertsIconListener);
-
   if (mIconRequest)
     mIconRequest->CancelAndForgetObserver(NS_BINDING_ABORTED);
-
-  if (!mHasQuit) {
-    nsCOMPtr<nsIObserverService> obsServ =
-        do_GetService("@mozilla.org/observer-service;1");
-    obsServ->RemoveObserver(this, "quit-application");
-  }
 }
 
 NS_IMETHODIMP
@@ -307,7 +294,6 @@ nsAlertsIconListener::Observe(nsISupports *aSubject, const char *aTopic,
     g_signal_handler_disconnect(mNotification, mClosureHandler);
     g_object_unref(mNotification);
     mNotification = NULL;
-    mHasQuit = PR_TRUE;
     Release(); // equivalent to NS_RELEASE(this)
   }
   return NS_OK;
@@ -364,6 +350,11 @@ nsAlertsIconListener::InitAlertAsync(const nsAString & aImageUrl,
   if (!gHasActions && aAlertTextClickable)
     return NS_ERROR_FAILURE; // No good, fallback to XUL
 
+  nsCOMPtr<nsIObserverService> obsServ =
+      do_GetService("@mozilla.org/observer-service;1");
+  if (obsServ)
+    obsServ->AddObserver(this, "quit-application", PR_TRUE);
+
   // Workaround for a libnotify bug - blank titles aren't dealt with
   // properly so we use a space
   if (aAlertTitle.IsEmpty()) {

toolkit/system/gnome/nsAlertsIconListener.h

@@ -42,6 +42,7 @@
 #include "imgIDecoderObserver.h"
 #include "nsStringAPI.h"
 #include "nsIObserver.h"
+#include "nsWeakReference.h"
 
 #include <gdk-pixbuf/gdk-pixbuf.h>
 #include <libnotify/notify.h>
@@ -49,7 +50,8 @@
 class imgIRequest;
 
 class nsAlertsIconListener : public imgIDecoderObserver,
-                             public nsIObserver
+                             public nsIObserver,
+                             public nsSupportsWeakReference
 {
 public:
   NS_DECL_ISUPPORTS
@@ -80,7 +82,6 @@ protected:
 
   PRPackedBool mLoadedFrame;
   PRPackedBool mAlertHasAction;
-  PRPackedBool mHasQuit;
 
   NotifyNotification* mNotification;
   gulong mClosureHandler;