QML engine internals: Do not require mutable QObject pointer

All we need is to get the meta-object from the object. This also works
with a const pointer, which is helpful for const-correctness in the FSM
framework.

Change-Id: Ie554fe81e67bced5f74c844c72e7f9b0df7ded58
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
(cherry picked from commit d0db469788039cf73406ba3f489b7a00b0601f01)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

5 files changed, 10 insertions, 12 deletions

diff --git a/src/qml/qml/qqmlboundsignal.cpp b/src/qml/qml/qqmlboundsignal.cpp
index 8fceb94f45..3626d8f9c0 100644
--- a/src/qml/qml/qqmlboundsignal.cpp
+++ b/src/qml/qml/qqmlboundsignal.cpp
@@ -64,8 +64,7 @@
 
 QT_BEGIN_NAMESPACE
 
-QQmlBoundSignalExpression::QQmlBoundSignalExpression(
-        QObject *target, int index, const QQmlRefPointer<QQmlContextData> &ctxt, QObject *scope,
+QQmlBoundSignalExpression::QQmlBoundSignalExpression(const QObject *target, int index, const QQmlRefPointer<QQmlContextData> &ctxt, QObject *scope,
         const QString &expression, const QString &fileName, quint16 line, quint16 column,
         const QString &handlerName, const QString &parameterString)
     : QQmlJavaScriptExpression(),
@@ -104,8 +103,7 @@ QQmlBoundSignalExpression::QQmlBoundSignalExpression(
     setupFunction(context, f->function());
 }
 
-QQmlBoundSignalExpression::QQmlBoundSignalExpression(
-        QObject *target, int index, const QQmlRefPointer<QQmlContextData> &ctxt,
+QQmlBoundSignalExpression::QQmlBoundSignalExpression(const QObject *target, int index, const QQmlRefPointer<QQmlContextData> &ctxt,
         QObject *scopeObject, QV4::Function *function, QV4::ExecutionContext *scope)
     : QQmlJavaScriptExpression(),
       m_index(index),
diff --git a/src/qml/qml/qqmlboundsignal_p.h b/src/qml/qml/qqmlboundsignal_p.h
index d034d874df..881c65db26 100644
--- a/src/qml/qml/qqmlboundsignal_p.h
+++ b/src/qml/qml/qqmlboundsignal_p.h
@@ -66,12 +66,12 @@ class Q_QML_PRIVATE_EXPORT QQmlBoundSignalExpression : public QQmlJavaScriptExpr
 {
 public:
     QQmlBoundSignalExpression(
-            QObject *target, int index, const QQmlRefPointer<QQmlContextData> &ctxt, QObject *scope,
+            const QObject *target, int index, const QQmlRefPointer<QQmlContextData> &ctxt, QObject *scope,
             const QString &expression, const QString &fileName, quint16 line, quint16 column,
             const QString &handlerName = QString(), const QString &parameterString = QString());
 
     QQmlBoundSignalExpression(
-            QObject *target, int index, const QQmlRefPointer<QQmlContextData> &ctxt,
+            const QObject *target, int index, const QQmlRefPointer<QQmlContextData> &ctxt,
             QObject *scopeObject, QV4::Function *function, QV4::ExecutionContext *scope = nullptr);
 
     // inherited from QQmlJavaScriptExpression.
@@ -83,7 +83,7 @@ public:
     void evaluate(const QList<QVariant> &args);
 
     QString expression() const;
-    QObject *target() const { return m_target; }
+    const QObject *target() const { return m_target; }
 
 private:
     ~QQmlBoundSignalExpression() override;
@@ -93,7 +93,7 @@ private:
     bool expressionFunctionValid() const { return function() != nullptr; }
 
     int m_index;
-    QObject *m_target;
+    const QObject *m_target;
 };
 
 class Q_QML_PRIVATE_EXPORT QQmlBoundSignal : public QQmlNotifierEndpoint
diff --git a/src/qml/qml/qqmlmetaobject_p.h b/src/qml/qml/qqmlmetaobject_p.h
index 9465458780..a5b9b758a8 100644
--- a/src/qml/qml/qqmlmetaobject_p.h
+++ b/src/qml/qml/qqmlmetaobject_p.h
@@ -75,7 +75,7 @@ public:
     typedef QVarLengthArray<int, 9> ArgTypeStorage;
 
     inline QQmlMetaObject() = default;
-    inline QQmlMetaObject(QObject *);
+    inline QQmlMetaObject(const QObject *);
     inline QQmlMetaObject(const QMetaObject *);
     inline QQmlMetaObject(QQmlPropertyCache *);
     inline QQmlMetaObject(const QQmlMetaObject &);
@@ -108,7 +108,7 @@ protected:
 
 };
 
-QQmlMetaObject::QQmlMetaObject(QObject *o)
+QQmlMetaObject::QQmlMetaObject(const QObject *o)
 {
     if (o)
         _m = o->metaObject();
diff --git a/src/qml/qml/qqmlpropertycache.cpp b/src/qml/qml/qqmlpropertycache.cpp
index 114c5fec10..854cba6f29 100644
--- a/src/qml/qml/qqmlpropertycache.cpp
+++ b/src/qml/qml/qqmlpropertycache.cpp
@@ -820,7 +820,7 @@ int QQmlPropertyCache::originalClone(int index)
     return index;
 }
 
-int QQmlPropertyCache::originalClone(QObject *object, int index)
+int QQmlPropertyCache::originalClone(const QObject *object, int index)
 {
     QQmlData *data = QQmlData::get(object, false);
     if (data && data->propertyCache) {
diff --git a/src/qml/qml/qqmlpropertycache_p.h b/src/qml/qml/qqmlpropertycache_p.h
index 1adfc53cf5..4c9395601c 100644
--- a/src/qml/qml/qqmlpropertycache_p.h
+++ b/src/qml/qml/qqmlpropertycache_p.h
@@ -196,7 +196,7 @@ public:
 
     //see QMetaObjectPrivate::originalClone
     int originalClone(int index);
-    static int originalClone(QObject *, int index);
+    static int originalClone(const QObject *, int index);
 
     QList<QByteArray> signalParameterNames(int index) const;
     static QString signalParameterStringForJS(QV4::ExecutionEngine *engine, const QList<QByteArray> &parameterNameList, QString *errorString = nullptr);