Oilpan: IDBCursor should be detached from IDBRequest when the IDBRequest stops

Source/core/workers/WorkerGlobalScope.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * Copyright (C) 2009, 2011 Google Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 178 matching lines @@
 
 void WorkerGlobalScope::willStopActiveDOMObjects()
 {
     lifecycleNotifier().notifyWillStopActiveDOMObjects();
 }
 
 void WorkerGlobalScope::dispose()
 {
     ASSERT(thread()->isCurrentThread());
 
+    if (m_script)
+        m_script->dispose();
+    lifecycleNotifier().notifyContextWillBeDestroyed();
+
     clearScript();

[haraken, 2014/04/01 05:56:14]

I'm afraid this is very hacky. This code is the way it is to make sure that
things happen in the following order:

(1) DOMWrapperWorld is disposed.
(2) contextWillBeDestroyed() is called on IDBRequest objects, and they die.
(3) didStopWorkerRunLoop() notification is sent to the Chromium side.
(4) ThreadState::detach() is called.
(5) Isolate is disposed.

[Mads Ager (chromium), 2014/04/01 11:38:38]

This code is one big hair ball already where things have to happen in exactly
the right order for things to die properly. I'm not sure this is much worse than
it was before? Maybe some comments on the shutdown order would be in order.

     clearInspector();
     setClient(0);
 
     // We do not clear the thread field of the
     // WorkerGlobalScope. Other objects keep the worker global scope
     // alive because they need its thread field to check that work is
     // being carried out on the right thread. We therefore cannot clear
     // the thread field before all references to the worker global
     // scope are gone.
 }
@@ skipping 93 matching lines @@
 {
     visitor->trace(m_console);
     visitor->trace(m_location);
     visitor->trace(m_navigator);
 #if ENABLE(OILPAN)
     HeapSupplementable<WorkerGlobalScope>::trace(visitor);
 #endif
 }
 
 } // namespace WebCore