Merge pull request #7155 from jherico/script_engine_crash

Fix a number of crashes / hangs on exit

libraries/fbx/src/OBJReader.cpp

@@ -260,10 +260,22 @@ QNetworkReply* OBJReader::request(QUrl& url, bool isTest) {
     QNetworkAccessManager& networkAccessManager = NetworkAccessManager::getInstance();
     QNetworkRequest netRequest(url);
     QNetworkReply* netReply = isTest ? networkAccessManager.head(netRequest) : networkAccessManager.get(netRequest);
+    if (!qApp) {
+        return netReply;
+    }
     QEventLoop loop; // Create an event loop that will quit when we get the finished signal
     QObject::connect(netReply, SIGNAL(finished()), &loop, SLOT(quit()));
     loop.exec();                    // Nothing is going to happen on this whole run thread until we get this
-    netReply->waitForReadyRead(-1); // so we might as well block this thread waiting for the response, rather than
+
+    bool aboutToQuit { false };
+    auto connection = QObject::connect(qApp, &QCoreApplication::aboutToQuit, [&] {
+        aboutToQuit = true;
+    });
+    static const int WAIT_TIMEOUT_MS = 500;
+    while (qApp && !aboutToQuit && !netReply->isReadable()) {
+        netReply->waitForReadyRead(WAIT_TIMEOUT_MS); // so we might as well block this thread waiting for the response, rather than
+    }
+    QObject::disconnect(connection);
     return netReply;                // trying to sync later on.
 }
 

libraries/gl/src/gl/OffscreenQmlSurface.cpp

@@ -315,6 +315,8 @@ OffscreenQmlSurface::OffscreenQmlSurface() {
 }
 
 OffscreenQmlSurface::~OffscreenQmlSurface() {
+    QObject::disconnect(&_updateTimer);
+    QObject::disconnect(qApp);
     _renderer->stop();
     delete _rootItem;
     delete _renderer;
@@ -322,6 +324,10 @@ OffscreenQmlSurface::~OffscreenQmlSurface() {
     delete _qmlEngine;
 }
 
+void OffscreenQmlSurface::onAboutToQuit() {
+    QObject::disconnect(&_updateTimer);
+}
+
 void OffscreenQmlSurface::create(QOpenGLContext* shareContext) {
     _renderer = new OffscreenQmlRenderer(this, shareContext);
     _renderer->_renderControl->_renderWindow = _proxyWindow;
@@ -334,12 +340,9 @@ void OffscreenQmlSurface::create(QOpenGLContext* shareContext) {
     // When Quick says there is a need to render, we will not render immediately. Instead,
     // a timer with a small interval is used to get better performance.
     _updateTimer.setInterval(MIN_TIMER_MS);
-    connect(&_updateTimer, &QTimer::timeout, this, &OffscreenQmlSurface::updateQuick);
+    QObject::connect(&_updateTimer, &QTimer::timeout, this, &OffscreenQmlSurface::updateQuick);
-    QObject::connect(qApp, &QCoreApplication::aboutToQuit, [this]{
+    QObject::connect(qApp, &QCoreApplication::aboutToQuit, this, &OffscreenQmlSurface::onAboutToQuit);
-        disconnect(&_updateTimer, &QTimer::timeout, this, &OffscreenQmlSurface::updateQuick);
-    });
     _updateTimer.start();
-
     _qmlComponent = new QQmlComponent(_qmlEngine);
     _qmlEngine->rootContext()->setContextProperty("offscreenWindow", QVariant::fromValue(getWindow()));
 }

libraries/gl/src/gl/OffscreenQmlSurface.h

@@ -74,6 +74,7 @@ signals:
 public slots:
     void requestUpdate();
     void requestRender();
+    void onAboutToQuit();
 
 private:
     QObject* finishQmlLoad(std::function<void(QQmlContext*, QObject*)> f);

libraries/script-engine/src/ScriptEngine.cpp

@@ -144,7 +144,12 @@ ScriptEngine::ScriptEngine(const QString& scriptContents, const QString& fileNam
 ScriptEngine::~ScriptEngine() {
     qCDebug(scriptengine) << "Script Engine shutting down (destructor) for script:" << getFilename();
 
-    DependencyManager::get<ScriptEngines>()->removeScriptEngine(this);
+    auto scriptEngines = DependencyManager::get<ScriptEngines>();
+    if (scriptEngines) {
+        scriptEngines->removeScriptEngine(this);
+    } else {
+        qCWarning(scriptengine) << "Script destroyed after ScriptEngines!";
+    }
 }
 
 void ScriptEngine::disconnectNonEssentialSignals() {