[webkit-dev] QtConnectionObjects not cleaned up for QtOwnership objects

[Kenneth Christiansen]

This should go to the webkit-qt at lists.webkit.org list instead. Please repost
there.

Creating a bug report on bugs.webkit.org for tracking your issues is another
welcome option.

Kenneth

On Tue, Dec 15, 2009 at 5:24 PM, Andrew Webster <apwebster at gmail.com> wrote:

> For all the Qt people out there, here is my problem:
>
> We have quite a few QObjects that we are inserting into JavaScript
> using addToJavaScriptWindowObject, however because we have limited
> resources and are creating so many of these objects, we would prefer
> that they are NOT ScriptOwnership objects so that there is not as much
> duplication for each frame.  This presents a problem when it comes to
> using 'connect' to handle signals.  Each connect creates a
> QtConnectionObject which references the JSHTMLDocument object.  The
> QtConnectionObject is never destroyed because the QObject is never
> destroyed, and this prevents most of the objects from being cleaned up
> by the gc when the page is refreshed leading to a significant memory
> leak.
>
> The solution I'm working on essentially makes the QtConnectionObject
> 'script owned' so that it is cleaned up when the script is destroyed:
>
> Index: qt_runtime.cpp
> ===================================================================
> --- qt_runtime.cpp      (revision 52150)
> +++ qt_runtime.cpp      (working copy)
> @@ -1527,6 +1527,11 @@
>                 else {
>                     // Store connection
>                     connections.insert(sender, conn);
> +                    // also create a script wrapper for the
> connection object, but make sure that it is destroyed when
> +                    // the script goes away
> +                    d->m_instance->rootObject()->gcProtect(
> +                       QtInstance::getQtInstance(conn,
> d->m_instance->rootObject(), QScriptEngine::ScriptOwnership)->
> +
> createRuntimeObject(exec->dynamicGlobalObject()->globalExec()));
>                 }
>             } else {
>                 // Now to find our previous connection object. Hmm.
>
> This seems to be working in my limited tests.  Can anyone comment on
> the validity of this solution?
>
>
> Thanks,
> Andrew
> _______________________________________________
> webkit-dev mailing list
> webkit-dev at lists.webkit.org
> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
>



-- 
Kenneth Rohde Christiansen
Technical Lead / Senior Software Engineer
Qt Labs Americas, Nokia Technology Institute, INdT
Phone  +55 81 8895 6002 / E-mail kenneth.christiansen at openbossa.org
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