QmlJS/C++: Fix possible crash on exit.

It could crash if a thread to find exported cpp types was still running
after the ModelManager was destroyed.

Change-Id: Ia48fac9c2ad1296992af83af57e84cce8c4f95ae
Reviewed-by: Leandro T. C. Melo <leandro.melo@nokia.com>

src/plugins/qmljstools/qmljsmodelmanager.cpp

@@ -133,6 +133,12 @@ ModelManager::ModelManager(QObject *parent):
     updateImportPaths();
 }
 
+ModelManager::~ModelManager()
+{
+    m_cppQmlTypesUpdater.cancel();
+    m_cppQmlTypesUpdater.waitForFinished();
+}
+
 void ModelManager::delayedInitialization()
 {
     CPlusPlus::CppModelManagerInterface *cppModelManager =
@@ -724,27 +730,37 @@ void ModelManager::queueCppQmlTypeUpdate(const CPlusPlus::Document::Ptr &doc, bo
 
 void ModelManager::startCppQmlTypeUpdate()
 {
+    // if a future is still running, delay
+    if (m_cppQmlTypesUpdater.isRunning()) {
+        m_updateCppQmlTypesTimer->start();
+        return;
+    }
+
     CPlusPlus::CppModelManagerInterface *cppModelManager =
             CPlusPlus::CppModelManagerInterface::instance();
     if (!cppModelManager)
         return;
 
-    QtConcurrent::run(&ModelManager::updateCppQmlTypes,
+    m_cppQmlTypesUpdater = QtConcurrent::run(
-                      this, cppModelManager, m_queuedCppDocuments);
+                &ModelManager::updateCppQmlTypes,
+                this, cppModelManager->snapshot(), m_queuedCppDocuments);
     m_queuedCppDocuments.clear();
 }
 
-void ModelManager::updateCppQmlTypes(ModelManager *qmlModelManager,
+void ModelManager::updateCppQmlTypes(QFutureInterface<void> &interface,
-                                     CPlusPlus::CppModelManagerInterface *cppModelManager,
+                                     ModelManager *qmlModelManager,
+                                     CPlusPlus::Snapshot snapshot,
                                      QHash<QString, QPair<CPlusPlus::Document::Ptr, bool> > documents)
 {
     CppDataHash newData = qmlModelManager->cppData();
 
-    CPlusPlus::Snapshot snapshot = cppModelManager->snapshot();
     FindExportedCppTypes finder(snapshot);
 
     typedef QPair<CPlusPlus::Document::Ptr, bool> DocScanPair;
     foreach (const DocScanPair &pair, documents) {
+        if (interface.isCanceled())
+            return;
+
         CPlusPlus::Document::Ptr doc = pair.first;
         const bool scan = pair.second;
         const QString fileName = doc->fileName();

src/plugins/qmljstools/qmljsmodelmanager.h

@@ -69,6 +69,7 @@ class QMLJSTOOLS_EXPORT ModelManager: public QmlJS::ModelManagerInterface
 
 public:
     ModelManager(QObject *parent = 0);
+    ~ModelManager();
 
     void delayedInitialization();
 
@@ -129,8 +130,9 @@ private slots:
 
 private:
     static bool matchesMimeType(const Core::MimeType &fileMimeType, const Core::MimeType &knownMimeType);
-    static void updateCppQmlTypes(ModelManager *qmlModelManager,
+    static void updateCppQmlTypes(QFutureInterface<void> &interface,
-                                  CPlusPlus::CppModelManagerInterface *cppModelManager,
+                                  ModelManager *qmlModelManager,
+                                  CPlusPlus::Snapshot snapshot,
                                   QHash<QString, QPair<CPlusPlus::Document::Ptr, bool> > documents);
 
     mutable QMutex m_mutex;
@@ -144,6 +146,7 @@ private:
 
     QTimer *m_updateCppQmlTypesTimer;
     QHash<QString, QPair<CPlusPlus::Document::Ptr, bool> > m_queuedCppDocuments;
+    QFuture<void> m_cppQmlTypesUpdater;
 
     CppDataHash m_cppDataHash;
     mutable QMutex m_cppDataMutex;