QtStateMachine QML-facing properties' bindable support part 2

This commit covers these QML-facing classes:
SignalTransition

Task-number: QTBUG-91375
Change-Id: I58bca7b4599b420aa99492233f9d88ea4af7e877
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

3 files changed, 36 insertions, 17 deletions

diff --git a/src/statemachineqml/CMakeLists.txt b/src/statemachineqml/CMakeLists.txt
index cd3331f..a30d76a 100644
--- a/src/statemachineqml/CMakeLists.txt
+++ b/src/statemachineqml/CMakeLists.txt
@@ -14,6 +14,8 @@ qt_internal_add_module(StateMachineQml
         Qt::Core
         Qt::Qml
         Qt::StateMachine
+    LIBRARIES
+        Qt::QmlPrivate
 )
 
 set_target_properties(StateMachineQml PROPERTIES
diff --git a/src/statemachineqml/signaltransition.cpp b/src/statemachineqml/signaltransition.cpp
index 16c2e0c..f082b0a 100644
--- a/src/statemachineqml/signaltransition.cpp
+++ b/src/statemachineqml/signaltransition.cpp
@@ -54,7 +54,7 @@
 SignalTransition::SignalTransition(QState *parent)
     : QSignalTransition(this, SIGNAL(invokeYourself()), parent), m_complete(false), m_signalExpression(nullptr)
 {
-    connect(this, SIGNAL(signalChanged()), SIGNAL(qmlSignalChanged()));
+    connect(this, &SignalTransition::signalChanged, [this](){ m_signal.notify(); });
 }
 
 bool SignalTransition::eventTest(QEvent *event)
@@ -63,7 +63,7 @@ bool SignalTransition::eventTest(QEvent *event)
     if (!QSignalTransition::eventTest(event))
         return false;
 
-    if (m_guard.isEmpty())
+    if (m_guard.value().isEmpty())
         return true;
 
     QQmlContext *outerContext = QQmlEngine::contextForObject(this);
@@ -79,7 +79,7 @@ bool SignalTransition::eventTest(QEvent *event)
     for (int i = 0; i < count; i++)
         context.setContextProperty(QString::fromUtf8(parameterNames[i]), QVariant::fromValue(e->arguments().at(i)));
 
-    QQmlExpression expr(m_guard, &context, this);
+    QQmlExpression expr(m_guard.value(), &context, this);
     QVariant result = expr.evaluate();
 
     return result.toBool();
@@ -101,8 +101,10 @@ const QJSValue& SignalTransition::signal()
 
 void SignalTransition::setSignal(const QJSValue &signal)
 {
-    if (m_signal.strictlyEquals(signal))
+    if (m_signal.value().strictlyEquals(signal)) {
+        m_signal.removeBindingUnlessInWrapper();
         return;
+    }
 
     QV4::ExecutionEngine *jsEngine = QQmlEngine::contextForObject(this)->engine()->handle();
     QV4::Scope scope(jsEngine);
@@ -111,16 +113,15 @@ void SignalTransition::setSignal(const QJSValue &signal)
     QMetaMethod signalMethod;
 
     m_signal = signal;
-    QJSValuePrivate::manageStringOnV4Heap(jsEngine, &m_signal);
-
-    QV4::ScopedValue value(scope, QJSValuePrivate::asReturnedValue(&m_signal));
+    QV4::ScopedValue value(scope, QJSValuePrivate::asReturnedValue(&signal));
 
     // Did we get the "slot" that can be used to invoke the signal?
     if (QV4::QObjectMethod *signalSlot = value->as<QV4::QObjectMethod>()) {
         sender = signalSlot->object();
         Q_ASSERT(sender);
         signalMethod = sender->metaObject()->method(signalSlot->methodIndex());
-    } else if (QV4::QmlSignalHandler *signalObject = value->as<QV4::QmlSignalHandler>()) { // or did we get the signal object (the one with the connect()/disconnect() functions) ?
+    } else if (QV4::QmlSignalHandler *signalObject = value->as<QV4::QmlSignalHandler>()) {
+        // or did we get the signal object (the one with the connect()/disconnect() functions) ?
         sender = signalObject->object();
         Q_ASSERT(sender);
         signalMethod = sender->metaObject()->method(signalObject->signalIndex());
@@ -130,11 +131,17 @@ void SignalTransition::setSignal(const QJSValue &signal)
     }
 
     QSignalTransition::setSenderObject(sender);
+    // the call below will emit change signal, and the interceptor lambda in ctor will notify()
     QSignalTransition::setSignal(signalMethod.methodSignature());
 
     connectTriggered();
 }
 
+QBindable<QJSValue> SignalTransition::bindableSignal()
+{
+    return &m_signal;
+}
+
 QQmlScriptString SignalTransition::guard() const
 {
     return m_guard;
@@ -142,11 +149,12 @@ QQmlScriptString SignalTransition::guard() const
 
 void SignalTransition::setGuard(const QQmlScriptString &guard)
 {
-    if (m_guard == guard)
-        return;
-
     m_guard = guard;
-    emit guardChanged();
+}
+
+QBindable<QQmlScriptString> SignalTransition::bindableGuard()
+{
+    return &m_guard;
 }
 
 void SignalTransition::invoke()
@@ -169,7 +177,8 @@ void SignalTransition::connectTriggered()
 
     QV4::ExecutionEngine *jsEngine = QQmlEngine::contextForObject(this)->engine()->handle();
     QV4::Scope scope(jsEngine);
-    QV4::Scoped<QV4::QObjectMethod> qobjectSignal(scope, QJSValuePrivate::asReturnedValue(&m_signal));
+    QV4::Scoped<QV4::QObjectMethod> qobjectSignal(
+                scope, QJSValuePrivate::asReturnedValue(&m_signal.value()));
     Q_ASSERT(qobjectSignal);
     QMetaMethod metaMethod = target->metaObject()->method(qobjectSignal->methodIndex());
     int signalIndex = QMetaObjectPrivate::signalIndex(metaMethod);
diff --git a/src/statemachineqml/signaltransition_p.h b/src/statemachineqml/signaltransition_p.h
index b8b3346..03e3b1b 100644
--- a/src/statemachineqml/signaltransition_p.h
+++ b/src/statemachineqml/signaltransition_p.h
@@ -62,6 +62,7 @@
 #include <private/qqmlcustomparser_p.h>
 #include <private/qqmlrefcount_p.h>
 #include <private/qqmlboundsignal_p.h>
+#include <QtCore/private/qproperty_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -69,8 +70,10 @@ class Q_STATEMACHINEQML_PRIVATE_EXPORT SignalTransition : public QSignalTransiti
 {
     Q_OBJECT
     Q_INTERFACES(QQmlParserStatus)
-    Q_PROPERTY(QJSValue signal READ signal WRITE setSignal NOTIFY qmlSignalChanged)
-    Q_PROPERTY(QQmlScriptString guard READ guard WRITE setGuard NOTIFY guardChanged)
+    Q_PROPERTY(QJSValue signal READ signal WRITE setSignal
+               NOTIFY qmlSignalChanged BINDABLE bindableSignal)
+    Q_PROPERTY(QQmlScriptString guard READ guard WRITE setGuard
+               NOTIFY guardChanged BINDABLE bindableGuard)
     QML_ELEMENT
     QML_ADDED_IN_VERSION(1, 0)
     QML_CUSTOMPARSER
@@ -80,12 +83,14 @@ public:
 
     QQmlScriptString guard() const;
     void setGuard(const QQmlScriptString &guard);
+    QBindable<QQmlScriptString> bindableGuard();
 
     bool eventTest(QEvent *event) override;
     void onTransition(QEvent *event) override;
 
     const QJSValue &signal();
     void setSignal(const QJSValue &signal);
+    QBindable<QJSValue> bindableSignal();
 
     Q_INVOKABLE void invoke();
 
@@ -103,8 +108,11 @@ private:
     void connectTriggered();
 
     friend class SignalTransitionParser;
-    QJSValue m_signal;
-    QQmlScriptString m_guard;
+
+    Q_OBJECT_COMPAT_PROPERTY(SignalTransition, QJSValue, m_signal, &SignalTransition::setSignal,
+                             &SignalTransition::qmlSignalChanged);
+    Q_OBJECT_BINDABLE_PROPERTY(SignalTransition, QQmlScriptString,
+                               m_guard, &SignalTransition::guardChanged);
     bool m_complete;
     QQmlRefPointer<QV4::ExecutableCompilationUnit> m_compilationUnit;
     QList<const QV4::CompiledData::Binding *> m_bindings;