Make it possible to connect to QAbstract{State,Transtion} private signals.

Use the same trick as used for private signals in the models.

Change-Id: I4235788490cae0e3d554565621d145652dc5b0ca
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>

src/corelib/statemachine/qabstractstate.cpp

@@ -119,13 +119,13 @@ void QAbstractStatePrivate::callOnExit(QEvent *e)
 void QAbstractStatePrivate::emitEntered()
 {
     Q_Q(QAbstractState);
-    emit q->entered();
+    emit q->entered(QAbstractState::QPrivateSignal());
 }
 
 void QAbstractStatePrivate::emitExited()
 {
     Q_Q(QAbstractState);
-    emit q->exited();
+    emit q->exited(QAbstractState::QPrivateSignal());
 }
 
 /*!

src/corelib/statemachine/qabstractstate.h

@@ -65,11 +65,16 @@ public:
     QStateMachine *machine() const;
 
 Q_SIGNALS:
-#if !defined(Q_MOC_RUN) && !defined(qdoc)
-private: // can only be emitted by QAbstractState
+    void entered(
+#if !defined(qdoc)
+      QPrivateSignal
 #endif
-    void entered();
-    void exited();
+    );
+    void exited(
+#if !defined(qdoc)
+      QPrivateSignal
+#endif
+    );
 
 protected:
     QAbstractState(QState *parent = 0);

src/corelib/statemachine/qabstracttransition.cpp

@@ -145,7 +145,7 @@ QState *QAbstractTransitionPrivate::sourceState() const
 void QAbstractTransitionPrivate::emitTriggered()
 {
     Q_Q(QAbstractTransition);
-    emit q->triggered();
+    emit q->triggered(QAbstractTransition::QPrivateSignal());
 }
 
 /*!

src/corelib/statemachine/qabstracttransition.h

@@ -88,10 +88,11 @@ public:
 #endif
 
 Q_SIGNALS:
-#if !defined(Q_MOC_RUN) && !defined(qdoc)
-private: // can only be emitted by QAbstractTransition
+    void triggered(
+#if !defined(qdoc)
+      QPrivateSignal
 #endif
-    void triggered();
+    );
 
 protected:
     virtual bool eventTest(QEvent *event) = 0;

tests/auto/corelib/statemachine/qstate/tst_qstate.cpp

@@ -57,6 +57,7 @@ private slots:
     void assignPropertyTwice();
     void historyInitialState();
     void transitions();
+    void privateSignals();
 
 private:
     bool functionCalled;
@@ -237,5 +238,125 @@ void tst_QState::transitions()
     QCOMPARE(s21->transitions().first(), t3);
 }
 
+class MyState : public QState
+{
+    Q_OBJECT
+public:
+    MyState(QState *parent = 0)
+      : QState(parent)
+    {
+
+    }
+
+    void emitPrivateSignals()
+    {
+        // These deliberately do not compile
+//         emit entered();
+//         emit exited();
+//
+//         emit entered(QPrivateSignal());
+//         emit exited(QPrivateSignal());
+//
+//         emit entered(QAbstractState::QPrivateSignal());
+//         emit exited(QAbstractState::QPrivateSignal());
+    }
+
+};
+
+class MyTransition : public QSignalTransition
+{
+    Q_OBJECT
+public:
+    MyTransition(QObject * sender, const char * signal, QState *sourceState = 0)
+      : QSignalTransition(sender, signal, sourceState)
+    {
+
+    }
+
+    void emitPrivateSignals()
+    {
+        // These deliberately do not compile
+//         emit triggered();
+//
+//         emit triggered(QPrivateSignal());
+//
+//         emit triggered(QAbstractTransition::QPrivateSignal());
+    }
+};
+
+class SignalConnectionTester : public QObject
+{
+    Q_OBJECT
+public:
+    SignalConnectionTester(QObject *parent = 0)
+      : QObject(parent), testPassed(false)
+    {
+
+    }
+
+public Q_SLOTS:
+    void testSlot()
+    {
+      testPassed = true;
+    }
+
+public:
+    bool testPassed;
+};
+
+class TestTrigger : public QObject
+{
+  Q_OBJECT
+public:
+    TestTrigger(QObject *parent = 0)
+      : QObject(parent)
+    {
+
+    }
+
+    void emitTrigger()
+    {
+        emit trigger();
+    }
+
+signals:
+    void trigger();
+};
+
+void tst_QState::privateSignals()
+{
+    QStateMachine machine;
+
+    QState *s1 = new QState(&machine);
+    MyState *s2 = new MyState(&machine);
+
+    TestTrigger testTrigger;
+
+    MyTransition *t1 = new MyTransition(&testTrigger, SIGNAL(trigger()), s1);
+    s1->addTransition(t1);
+    t1->setTargetState(s2);
+
+    machine.setInitialState(s1);
+    machine.start();
+    QCoreApplication::processEvents();
+
+    SignalConnectionTester s1Tester;
+    SignalConnectionTester s2Tester;
+    SignalConnectionTester t1Tester;
+
+    QObject::connect(s1, &QState::exited, &s1Tester, &SignalConnectionTester::testSlot);
+    QObject::connect(s2, &QState::entered, &s2Tester, &SignalConnectionTester::testSlot);
+    QObject::connect(t1, &QSignalTransition::triggered, &t1Tester, &SignalConnectionTester::testSlot);
+
+    testTrigger.emitTrigger();
+
+    QCoreApplication::processEvents();
+
+    QVERIFY(s1Tester.testPassed);
+    QVERIFY(s2Tester.testPassed);
+    QVERIFY(t1Tester.testPassed);
+
+}
+
 QTEST_MAIN(tst_QState)
 #include "tst_qstate.moc"