Make the event notification on Windows be mandatory in all dispatchers

This way, QWinEventNotifier will work on all Windows systems, not just
with the default event dispatcher. Other dispatchers (other than
QWin32EventDispatcher) are permitted, so the class should not abort just
because of that.

If a dispatcher really doesn't want to implement this, they need to
implement the virtuals to do nothing, possibly print a warning.

Change-Id: I2c132bcde95b9d5941c8906a0fcd2ad964087772
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>

src/corelib/kernel/qabstracteventdispatcher.h

@@ -53,6 +53,10 @@ QT_BEGIN_NAMESPACE
 class QAbstractEventDispatcherPrivate;
 class QSocketNotifier;
 
+#ifdef Q_OS_WIN
+class QWinEventNotifier;
+#endif
+
 class Q_CORE_EXPORT QAbstractEventDispatcher : public QObject
 {
     Q_OBJECT
@@ -95,6 +99,11 @@ public:
 
     virtual int remainingTime(int timerId) = 0;
 
+#ifdef Q_OS_WIN
+    virtual bool registerEventNotifier(QWinEventNotifier *notifier) = 0;
+    virtual void unregisterEventNotifier(QWinEventNotifier *notifier) = 0;
+#endif
+
     virtual void wakeUp() = 0;
     virtual void interrupt() = 0;
     virtual void flush() = 0;

src/corelib/kernel/qwineventnotifier.cpp

@@ -134,10 +134,12 @@ QWinEventNotifier::QWinEventNotifier(HANDLE hEvent, QObject *parent)
  : QObject(*new QWinEventNotifierPrivate(hEvent, false), parent)
 {
     Q_D(QWinEventNotifier);
-    QEventDispatcherWin32 *eventDispatcher = qobject_cast<QEventDispatcherWin32 *>(d->threadData->eventDispatcher);
-    Q_ASSERT_X(eventDispatcher, "QWinEventNotifier::QWinEventNotifier()",
-               "Cannot create a win event notifier without a QEventDispatcherWin32");
-    eventDispatcher->registerEventNotifier(this);
+    QAbstractEventDispatcher *eventDispatcher = d->threadData->eventDispatcher;
+    if (!eventDispatcher) {
+        qWarning("QWinEventNotifier: Can only be used with threads started with QThread");
+    } else {
+        eventDispatcher->registerEventNotifier(this);
+    }
     d->enabled = true;
 }
 
@@ -205,7 +207,7 @@ void QWinEventNotifier::setEnabled(bool enable)
         return;
     d->enabled = enable;
 
-    QEventDispatcherWin32 *eventDispatcher = qobject_cast<QEventDispatcherWin32 *>(d->threadData->eventDispatcher);
+    QAbstractEventDispatcher *eventDispatcher = d->threadData->eventDispatcher;
     if (!eventDispatcher) // perhaps application is shutting down
         return;
 

tests/auto/corelib/kernel/qcoreapplication/tst_qcoreapplication.cpp

@@ -622,6 +622,11 @@ public:
     void interrupt() {}
     void flush() {}
 
+#ifdef Q_OS_WIN
+    bool registerEventNotifier(QWinEventNotifier *) { return false; }
+    void unregisterEventNotifier(QWinEventNotifier *) { }
+#endif
+
     bool visited;
 };
 

tests/auto/corelib/thread/qthread/tst_qthread.cpp

@@ -1239,6 +1239,11 @@ public:
     void interrupt() {}
     void flush() {}
 
+#ifdef Q_OS_WIN
+    bool registerEventNotifier(QWinEventNotifier *) { return false; }
+    void unregisterEventNotifier(QWinEventNotifier *) { }
+#endif
+
     bool visited;
 };
 

tests/auto/testlib/selftests/benchlibeventcounter/tst_benchlibeventcounter.cpp

@@ -64,6 +64,11 @@ public:
     bool unregisterTimers(QObject*) { return false; }
     int remainingTime(int) { return 0; }
     void wakeUp() {}
+
+#ifdef Q_OS_WIN
+    bool registerEventNotifier(QWinEventNotifier *) { return false; }
+    void unregisterEventNotifier(QWinEventNotifier *) { }
+#endif
 };
 
 class tst_BenchlibEventCounter: public QObject

tests/auto/testlib/selftests/benchliboptions/tst_benchliboptions.cpp

@@ -64,6 +64,11 @@ public:
     bool unregisterTimers(QObject*) { return false; }
     int remainingTime(int) { return 0; }
     void wakeUp() {}
+
+#ifdef Q_OS_WIN
+    bool registerEventNotifier(QWinEventNotifier *) { return false; }
+    void unregisterEventNotifier(QWinEventNotifier *) { }
+#endif
 };
 
 class tst_BenchlibOptions: public QObject