Android: Fix data race in QAndroidEventDispatcherStopper

Change-Id: If5f8406d7af2d91e267a0ba380e73287feabac9f
Reviewed-by: BogDan Vatra <bogdan@kdab.com>

2 files changed, 4 insertions, 6 deletions

diff --git a/src/plugins/platforms/android/qandroideventdispatcher.cpp b/src/plugins/platforms/android/qandroideventdispatcher.cpp
index 104e905b8f..e12551283f 100644
--- a/src/plugins/platforms/android/qandroideventdispatcher.cpp
+++ b/src/plugins/platforms/android/qandroideventdispatcher.cpp
@@ -108,10 +108,9 @@ QAndroidEventDispatcherStopper *QAndroidEventDispatcherStopper::instance()
 void QAndroidEventDispatcherStopper::startAll()
 {
     QMutexLocker lock(&m_mutex);
-    if (started)
+    if (!m_started.testAndSetOrdered(0, 1))
         return;
 
-    started = true;
     for (QAndroidEventDispatcher *d : qAsConst(m_dispatchers))
         d->start();
 }
@@ -119,10 +118,9 @@ void QAndroidEventDispatcherStopper::startAll()
 void QAndroidEventDispatcherStopper::stopAll()
 {
     QMutexLocker lock(&m_mutex);
-    if (!started)
+    if (!m_started.testAndSetOrdered(1, 0))
         return;
 
-    started = false;
     for (QAndroidEventDispatcher *d : qAsConst(m_dispatchers))
         d->stop();
 }
diff --git a/src/plugins/platforms/android/qandroideventdispatcher.h b/src/plugins/platforms/android/qandroideventdispatcher.h
index 057a1660c9..e6f903bced 100644
--- a/src/plugins/platforms/android/qandroideventdispatcher.h
+++ b/src/plugins/platforms/android/qandroideventdispatcher.h
@@ -68,7 +68,7 @@ class QAndroidEventDispatcherStopper
 {
 public:
     static QAndroidEventDispatcherStopper *instance();
-    static bool stopped() {return !instance()->started; }
+    static bool stopped() {return !instance()->m_started.load(); }
     void startAll();
     void stopAll();
     void addEventDispatcher(QAndroidEventDispatcher *dispatcher);
@@ -77,7 +77,7 @@ public:
 
 private:
     QMutex m_mutex;
-    bool started = true;
+    QAtomicInt m_started = 1;
     QVector<QAndroidEventDispatcher *> m_dispatchers;
 };