Check for Q_GLOBAL_STATIC returning 0 (Sensor Gestures).

It's probably not very likely but during app shutdown, the
Q_GLOBAL_STATIC used in sensor gestures will start returning 0. Check
for this to avoid the chance of a crash.

Change-Id: I4b538ac9b9535bd9439a897d4eab51211c523e33
Reviewed-by: Lorn Potter <lorn.potter@nokia.com>

2 files changed, 19 insertions, 5 deletions

diff --git a/src/sensors/gestures/qsensorgesturemanager.cpp b/src/sensors/gestures/qsensorgesturemanager.cpp
index 20cdb34d..d85051ad 100644
--- a/src/sensors/gestures/qsensorgesturemanager.cpp
+++ b/src/sensors/gestures/qsensorgesturemanager.cpp
@@ -68,7 +68,9 @@ QT_BEGIN_NAMESPACE
 QSensorGestureManager::QSensorGestureManager(QObject *parent)
     : QObject(parent)
 {
-    connect(QSensorGestureManagerPrivate::instance(),SIGNAL(newSensorGestureAvailable()),
+    QSensorGestureManagerPrivate *d = QSensorGestureManagerPrivate::instance();
+    if (!d) return; // hardly likely but just in case...
+    connect(d,SIGNAL(newSensorGestureAvailable()),
             this,SIGNAL(newSensorGestureAvailable()));
 }
 
@@ -89,7 +91,12 @@ QSensorGestureManager::~QSensorGestureManager()
 
  bool QSensorGestureManager::registerSensorGestureRecognizer(QSensorGestureRecognizer *recognizer)
  {
-     bool ok = QSensorGestureManagerPrivate::instance()->registerSensorGestureRecognizer(recognizer);
+     QSensorGestureManagerPrivate *d = QSensorGestureManagerPrivate::instance();
+     if (!d) { // hardly likely but just in case...
+         delete recognizer;
+         return false;
+     }
+     bool ok = d->registerSensorGestureRecognizer(recognizer);
      if (!ok)
          delete recognizer;
 
@@ -103,7 +110,9 @@ QSensorGestureManager::~QSensorGestureManager()
    */
   QStringList QSensorGestureManager::gestureIds() const
  {
-      return QSensorGestureManagerPrivate::instance()->gestureIds();
+      QSensorGestureManagerPrivate *d = QSensorGestureManagerPrivate::instance();
+      if (!d) return QStringList(); // hardly likely but just in case...
+      return d->gestureIds();
  }
 
   /*!
@@ -123,7 +132,9 @@ QSensorGestureManager::~QSensorGestureManager()
   */
 QSensorGestureRecognizer *QSensorGestureManager::sensorGestureRecognizer(const QString &id)
 {
-    return QSensorGestureManagerPrivate::instance()->sensorGestureRecognizer(id);
+    QSensorGestureManagerPrivate *d = QSensorGestureManagerPrivate::instance();
+    if (!d) return 0; // hardly likely but just in case...
+    return d->sensorGestureRecognizer(id);
 }
 
 QT_END_NAMESPACE
diff --git a/src/sensors/gestures/qsensorgesturemanagerprivate.cpp b/src/sensors/gestures/qsensorgesturemanagerprivate.cpp
index 5e2089a9..fc22dc7c 100644
--- a/src/sensors/gestures/qsensorgesturemanagerprivate.cpp
+++ b/src/sensors/gestures/qsensorgesturemanagerprivate.cpp
@@ -236,7 +236,10 @@ void QSensorGestureManagerPrivate::recognizerStopped(const QSensorGestureRecogni
 
 QSensorGestureManagerPrivate * QSensorGestureManagerPrivate::instance()
 {
-    return sensorGestureManagerPrivate();
+    QSensorGestureManagerPrivate *priv = sensorGestureManagerPrivate();
+    // It's safe to return 0 because this is checked when used
+    //if (!priv) qFatal("Cannot return from QSensorGestureManagerPrivate::instance() because sensorGestureManagerPrivate() returned 0.");
+    return priv;
 }