Invalid memory access error

arvind2111

Hi,

I'm using qt-jambi to develop an app that goes through a list of URLs, loads them in a QtWebView page and then parses them for links. To force the app to be synchronous (i.e. completely finish with one page before moving onto the next), we exec a QEventLoop. In the event that a page takes too long to load, we have a timer that fires 30 seconds and forces the app to move on. However, after some random number of URLs, the app always segfaults and points to a different part of libQtWebkit. For example:

C [libQtWebKit.so.4+0x3ff181] WTF::TCMalloc_Central_FreeList::FetchFromSpans()+0x31

C [libQtWebKit.so.4+0x87d239] WebCore::QNetworkReplyHandler::sendResponseIfNeeded()+0xa09

and so forth.

What's interesting is if, in the loadFinished slot, we comment out the code that parses the page for links, there is never a segfault. Any ideas would be appreciated. A slimmed down version of the code is below or at http://pastiebin.com/?page=p&id=4f5bb860922e6

Thanks!

-Arvind

@public class PostProcess extends QMainWindow {
private QEventLoop mLoop;
private QWebView mBrowser;
private QTimer mTimer;

private String[] mPageData;
private int mPageIndex;

public PostProcess() {
        this(null);
    }

public PostProcess(QWidget parent) {
    super(parent);

    mLoop = new QEventLoop();

    mBrowser = new QWebView();
    setCentralWidget(mBrowser);

    mTimer = new QTimer();
    mTimer.setInterval(1000 * 30);
    mTimer.setSingleShot(true);
    mTimer.timeout.connect(this, "pageTimedOut()");
}

public static void main(String[] args) throws InterruptedException, IOException {          
    QApplication.initialize(args);
    
    PostProcess pp = new PostProcess();
    
    pp.run();
    
    QApplication.exit();
}

private void postProcess() {
    while (mPageIndex < mPageData.length) {
        String uri    = mPageData[mPageIndex];

        QNetworkAccessManager manager = new PostProcessNetworkAccessManager(pageId);
        mBrowser.page().setNetworkAccessManager(manager);
        mBrowser.page().settings().clearMemoryCaches();
        mBrowser.loadFinished.connect(this, "loadFinished(Boolean)");
        mBrowser.loadProgress.connect(this, "loadProgress(int)");
        
        QNetworkRequest req = new QNetworkRequest(new QUrl("http://" + uri));
        req.setRawHeader(FROM_CACHE, new QByteArray("1"));
        req.setRawHeader(PAGE_ID, new QByteArray(pageId));
        
        mTimer.start();
        
        mBrowser.load(req);
        
        mLoop.exec&#40;&#41;;   
        
        mPageIndex++;
    }
}

private void loadFinished(Boolean ok) { 
    debug("LOAD FINISHED: " + mBrowser.url() + " " + ok);
    mTimer.stop();

    mBrowser.loadFinished.disconnect();
    mBrowser.loadProgress.disconnect();
    mBrowser.stop();

    if(ok == true) {
        QWebElementCollection anchors = page.mainFrame().findAllElements("a");
     for(QWebElement anchor: anchors.toList())
         nextURIs.add(anchor.attribute("href"));
    }

    mLoop.exit();
}

private void loadProgress(int i) {
    System.err.print(i + "...");
}

private void pageTimedOut() {
    debug("TIMED OUT PAGE LOAD " + mBrowser.url());
    mBrowser.loadFinished.disconnect();
    mBrowser.loadProgress.disconnect();

    mBrowser.load(new QUrl("about:blank"));
    mLoop.exit();
}@