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Thread: QtWebKit with javascript: memory leak?

  1. #1

    Default QtWebKit with javascript: memory leak?


    I've written a software which browses multiple websites containing javascript.
    To achieve that, I'm using QWebPage with QWebSettings::JavascriptEnabled.
    The problem is that over the time the ram usage is constantly increasing, until more than 1-2 gb of ram is used and then crashes.
    I've written a little test snippet to demonstrate the issue.

    Ram usage
    • Without running the snippet: 7,7mb
    • With QWebSettings::JavascriptEnabled set to false: 40mb
    • With QWebSettings::JavascriptEnabled set to true: 110mb

    If you put some breakpoints, you can see the ram usage increasing with each site.

    Do you have any solution so that I can reduce the amount of ram used? I guess the problem is the page/frame isn't deleted because some javascript code is executed (maybe?). If so, any way to force the javascript to stop, once the page is loaded? Or perhaps a way to force the page to delete all its content?

    Qt Code:
    1. QWebPage page;
    2. page.settings()->setAttribute(QWebSettings::JavascriptEnabled, true);
    4. QEventLoop loop;
    5. connect(&page, SIGNAL(loadFinished(bool)), &loop, SLOT(quit()));
    7. for (int i=0; i<2; i++) {
    8. page.mainFrame()->load(QUrl(""));
    9. loop.exec();
    11. page.mainFrame()->load(QUrl(""));
    12. loop.exec();
    14. page.mainFrame()->load(QUrl(""));
    15. loop.exec();
    17. page.mainFrame()->load(QUrl(""));
    18. loop.exec();
    20. page.mainFrame()->load(QUrl(""));
    21. loop.exec();
    23. page.mainFrame()->load(QUrl(""));
    24. loop.exec();
    26. page.mainFrame()->load(QUrl(""));
    27. loop.exec();
    29. page.mainFrame()->load(QUrl(""));
    30. loop.exec();
    32. page.mainFrame()->load(QUrl(""));
    33. loop.exec();
    35. page.mainFrame()->load(QUrl(""));
    36. loop.exec();
    37. }
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    I'm using Qt 5.1 RC
    Last edited by monkazer; 19th June 2013 at 22:02.

  2. #2

    Default Re: QtWebKit with javascript: memory leak?

    Anyone? Please I really need to fix this issue...Is it a bug in Qt? The memory should be cleared once the QWebPage is destroyed.

  3. #3

    Default Re: QtWebKit with javascript: memory leak?

    Ok, I've found the issue. Sorry the code above wasn't totally accurate.
    In my app I have QWebSettings::AutoLoadImages disabled. It looks like if QWebSettings::JavascriptEnabled is enabled, we also need to enable QWebSettings::AutoLoadImages, otherwise the memory usage is a lot higher.
    I did the above test again without loading the images and the ram usage was 220mb!

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