webkit feedback calls on failure

Arunprasad Rajkumar arunprasad.rajkumar at oracle.com
Wed Sep 5 10:12:13 UTC 2018

Hi Johan,

Thanks for reporting this. I agree, there are few areas which needs improvement in WebView component, error handling is one among them. Please file a bug.


> On 04-Sep-2018, at 7:01 PM, Johan Vos <johan.vos at gluonhq.com> wrote:
> The WebEngine already allows to get information about the progress of the
> underlying webkit via the onError() handler and the getLoadWorker() status
> updates.
> However, there are a number of cases where things go wrong in webkit, yet
> the status of the loadWorker is SUCCEEDED and no WebErrorEvent is generated.
> A simple case is where a small html page loads a large image. In this case,
> URLLoader will call twkDidFinishLoading() which is a native call, which in
> turn will invoke ImageDecoderJava.cpp::setData
> This call will invoke
> WCImageDecoderImpl.addImageData (back in the java layer), but when that
> throws a throwable (which it does, an OOME in resizeDataArray), it will
> ignore it by calling CheckAndClearException (in ImageDecoderJava.cpp) and
> the information about the exception is lost (that
> is, env->ExceptionDescribe() is called which will print thread + exception,
> but that's it).
> Hence, at this moment it seems impossible to detect a failure when large
> images are loaded. While the status of the loadWorker will move to
> SUCCEEDED, the image won't be shown.
> There are a number of ways to improve this, so if it is agreed that this
> can be an enhancement, I'll file an issue for it.
> - Johan

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