Emit a notifications when childMode, initial and errorState are changed.

In order to properly use QState object in QML we need to know when these
properties are changed.

Change-Id: I37f8295e5201686a52d448cc42db331a8f8e792f
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Alan Alpert <aalpert@blackberry.com>
Reviewed-by: BogDan Vatra <bogdan@kde.org>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>

2 files changed, 57 insertions, 6 deletions

diff --git a/src/corelib/statemachine/qstate.cpp b/src/corelib/statemachine/qstate.cpp
index f3b4c5f235..e9baddc569 100644
--- a/src/corelib/statemachine/qstate.cpp
+++ b/src/corelib/statemachine/qstate.cpp
@@ -309,7 +309,10 @@ void QState::setErrorState(QAbstractState *state)
         return;
     }
 
-    d->errorState = state;
+    if (d->errorState != state) {
+        d->errorState = state;
+        emit errorStateChanged(QState::QPrivateSignal());
+    }
 }
 
 /*!
@@ -491,7 +494,10 @@ void QState::setInitialState(QAbstractState *state)
                  state, this);
         return;
     }
-    d->initialState = state;
+    if (d->initialState != state) {
+        d->initialState = state;
+        emit initialStateChanged(QState::QPrivateSignal());
+    }
 }
 
 /*!
@@ -509,7 +515,10 @@ QState::ChildMode QState::childMode() const
 void QState::setChildMode(ChildMode mode)
 {
     Q_D(QState);
-    d->childMode = mode;
+    if (d->childMode != mode) {
+        d->childMode = mode;
+        emit childModeChanged(QState::QPrivateSignal());
+    }
 }
 
 /*!
@@ -549,6 +558,33 @@ bool QState::event(QEvent *e)
   \sa QState::assignProperty(), QAbstractTransition::addAnimation()
 */
 
+/*!
+  \fn QState::childModeChanged()
+  \since 5.4
+
+  This signal is emitted when the childMode property is changed.
+
+  \sa QState::childMode
+*/
+
+/*!
+  \fn QState::initialStateChanged()
+  \since 5.4
+
+  This signal is emitted when the initialState property is changed.
+
+  \sa QState::initialState
+*/
+
+/*!
+  \fn QState::errorStateChanged()
+  \since 5.4
+
+  This signal is emitted when the errorState property is changed.
+
+  \sa QState::errorState
+*/
+
 QT_END_NAMESPACE
 
 #endif //QT_NO_STATEMACHINE
diff --git a/src/corelib/statemachine/qstate.h b/src/corelib/statemachine/qstate.h
index a5f2509ffb..09c98c30c6 100644
--- a/src/corelib/statemachine/qstate.h
+++ b/src/corelib/statemachine/qstate.h
@@ -58,9 +58,9 @@ class QStatePrivate;
 class Q_CORE_EXPORT QState : public QAbstractState
 {
     Q_OBJECT
-    Q_PROPERTY(QAbstractState* initialState READ initialState WRITE setInitialState)
-    Q_PROPERTY(QAbstractState* errorState READ errorState WRITE setErrorState)
-    Q_PROPERTY(ChildMode childMode READ childMode WRITE setChildMode)
+    Q_PROPERTY(QAbstractState* initialState READ initialState WRITE setInitialState NOTIFY initialStateChanged)
+    Q_PROPERTY(QAbstractState* errorState READ errorState WRITE setErrorState NOTIFY errorStateChanged)
+    Q_PROPERTY(ChildMode childMode READ childMode WRITE setChildMode NOTIFY childModeChanged)
     Q_ENUMS(ChildMode RestorePolicy)
 public:
     enum ChildMode {
@@ -108,6 +108,21 @@ Q_SIGNALS:
       QPrivateSignal
 #endif
     );
+    void childModeChanged(
+#if !defined(Q_QDOC)
+      QPrivateSignal
+#endif
+    );
+    void initialStateChanged(
+#if !defined(Q_QDOC)
+      QPrivateSignal
+#endif
+    );
+    void errorStateChanged(
+#if !defined(Q_QDOC)
+      QPrivateSignal
+#endif
+    );
 
 protected:
     void onEntry(QEvent *event);