Improve value type binding behavior

Changing value type bindings in state changes, and implicitly removing
them on property assignment was not reliable.  Internally the system
considered a binding on "font" and one on "font.x" as a binding on two
separate properties, even though the "font" binding completely
overrides the "font.x" property.

Following this change a binding to "font.x" creates a proxy binding object
on the "font" property in addition to the "font.x" binding itself.  This
allows behavior to be consistent across all operations.

QT-2920

1 files changed, 28 insertions, 0 deletions

diff --git a/src/declarative/qml/qdeclarativebinding_p.h b/src/declarative/qml/qdeclarativebinding_p.h
index 1a714f0..21e3248 100644
--- a/src/declarative/qml/qdeclarativebinding_p.h
+++ b/src/declarative/qml/qdeclarativebinding_p.h
@@ -74,6 +74,9 @@ public:
 
     virtual QString expression() const;
 
+    enum Type { PropertyBinding, ValueTypeProxy };
+    virtual Type bindingType() const { return PropertyBinding; }
+
     void setEnabled(bool e) { setEnabled(e, QDeclarativePropertyPrivate::DontRemoveBinding); }
     virtual void setEnabled(bool, QDeclarativePropertyPrivate::WriteFlags) = 0;
     virtual int propertyIndex() = 0;
@@ -92,6 +95,7 @@ private:
     friend class QDeclarativeProperty;
     friend class QDeclarativePropertyPrivate;
     friend class QDeclarativeVME;
+    friend class QDeclarativeValueTypeProxyBinding;
 
     QObject *m_object;
     QDeclarativeAbstractBinding **m_mePtr;
@@ -99,6 +103,30 @@ private:
     QDeclarativeAbstractBinding  *m_nextBinding;
 };
 
+class QDeclarativeValueTypeProxyBinding : public QDeclarativeAbstractBinding
+{
+public:
+    QDeclarativeValueTypeProxyBinding(QObject *o, int coreIndex);
+    virtual ~QDeclarativeValueTypeProxyBinding();
+
+    virtual Type bindingType() const { return ValueTypeProxy; }
+
+    virtual void setEnabled(bool, QDeclarativePropertyPrivate::WriteFlags);
+    virtual int propertyIndex();
+    virtual void update(QDeclarativePropertyPrivate::WriteFlags);
+
+    QDeclarativeAbstractBinding *binding(int propertyIndex);
+
+private:
+    void recursiveEnable(QDeclarativeAbstractBinding *, QDeclarativePropertyPrivate::WriteFlags);
+    void recursiveDisable(QDeclarativeAbstractBinding *);
+
+    friend class QDeclarativeAbstractBinding;
+    QObject *m_object;
+    int m_index;
+    QDeclarativeAbstractBinding *m_bindings;
+};
+
 class QDeclarativeContext;
 class QDeclarativeBindingPrivate;
 class Q_DECLARATIVE_EXPORT QDeclarativeBinding : public QDeclarativeExpression, public QDeclarativeAbstractBinding