Replace bindingType() method by a virtual getter

This removes the need to save some bits in the abstract binding
object, and should make it easier to move QQmlAbstractBinding
over to be reference counted.

Change-Id: Ib46cb3217f3dc462f1dcaa6153d90ea2f7401f48
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

7 files changed, 30 insertions, 32 deletions

diff --git a/src/qml/qml/qqmlabstractbinding.cpp b/src/qml/qml/qqmlabstractbinding.cpp
index 04fbb16764..4a081ae0e8 100644
--- a/src/qml/qml/qqmlabstractbinding.cpp
+++ b/src/qml/qml/qqmlabstractbinding.cpp
@@ -39,8 +39,8 @@
 
 QT_BEGIN_NAMESPACE
 
-QQmlAbstractBinding::QQmlAbstractBinding(BindingType bt)
-    : m_nextBindingPtr(bt)
+QQmlAbstractBinding::QQmlAbstractBinding()
+    : m_nextBinding(0)
 {
 }
 
@@ -79,7 +79,7 @@ void QQmlAbstractBinding::addToObject()
             QQmlAbstractBinding *b = data->bindings;
             while (b && b->targetPropertyIndex() != coreIndex)
                 b = b->nextBinding();
-            Q_ASSERT(b && b->bindingType() == QQmlAbstractBinding::ValueTypeProxy);
+            Q_ASSERT(b && b->isValueTypeProxy());
             proxy = static_cast<QQmlValueTypeProxyBinding *>(b);
         }
 
@@ -126,7 +126,7 @@ void QQmlAbstractBinding::removeFromObject()
             vtbinding = vtbinding->nextBinding();
             Q_ASSERT(vtbinding);
         }
-        Q_ASSERT(vtbinding->bindingType() == QQmlAbstractBinding::ValueTypeProxy);
+        Q_ASSERT(vtbinding->isValueTypeProxy());
 
         QQmlValueTypeProxyBinding *vtproxybinding =
             static_cast<QQmlValueTypeProxyBinding *>(vtbinding);
@@ -197,4 +197,9 @@ QString QQmlAbstractBinding::expression() const
     return QLatin1String("<Unknown>");
 }
 
+bool QQmlAbstractBinding::isValueTypeProxy() const
+{
+    return false;
+}
+
 QT_END_NAMESPACE
diff --git a/src/qml/qml/qqmlabstractbinding_p.h b/src/qml/qml/qqmlabstractbinding_p.h
index ccf525ef38..f72d6918a1 100644
--- a/src/qml/qml/qqmlabstractbinding_p.h
+++ b/src/qml/qml/qqmlabstractbinding_p.h
@@ -59,9 +59,6 @@ class Q_QML_PRIVATE_EXPORT QQmlAbstractBinding
 public:
     typedef QWeakPointer<QQmlAbstractBinding> Pointer;
 
-    enum BindingType { Binding = 0, ValueTypeProxy = 1 };
-    inline BindingType bindingType() const;
-
     void destroy() {
         removeFromObject();
         clear();
@@ -70,6 +67,8 @@ public:
 
     virtual QString expression() const;
 
+    virtual bool isValueTypeProxy() const;
+
     // Should return the encoded property index for the binding.  Should return this value
     // even if the binding is not enabled or added to an object.
     // Encoding is:  coreIndex | (valueTypeIndex << 16)
@@ -90,7 +89,7 @@ public:
     inline QQmlAbstractBinding *nextBinding() const;
 
 protected:
-    QQmlAbstractBinding(BindingType);
+    QQmlAbstractBinding();
     virtual ~QQmlAbstractBinding();
     void clear();
 
@@ -113,14 +112,7 @@ private:
     inline void setNextBinding(QQmlAbstractBinding *);
 
     // Pointer to the next binding in the linked list of bindings.
-    // Being a pointer, the address is always aligned to at least 4 bytes, which means the last two
-    // bits of the pointer are free to be used for something else. They are used to store the binding
-    // type. The binding type serves as an index into the static vTables array, which is used instead
-    // of a compiler-generated vTable. Instead of virtual functions, pointers to static functions in
-    // the vTables array are used for dispatching.
-    // This saves a compiler-generated pointer to a compiler-generated vTable, and thus reduces
-    // the binding object size by sizeof(void*).
-    qintptr m_nextBindingPtr;
+    QQmlAbstractBinding *m_nextBinding;
 
 protected:
     QFlagPointer<QObject> m_target;
@@ -145,17 +137,12 @@ bool QQmlAbstractBinding::isAddedToObject() const
 
 QQmlAbstractBinding *QQmlAbstractBinding::nextBinding() const
 {
-    return (QQmlAbstractBinding *)(m_nextBindingPtr & ~0x3);
+    return m_nextBinding;
 }
 
 void QQmlAbstractBinding::setNextBinding(QQmlAbstractBinding *b)
 {
-    m_nextBindingPtr = qintptr(b) | (m_nextBindingPtr & 0x3);
-}
-
-QQmlAbstractBinding::BindingType QQmlAbstractBinding::bindingType() const
-{
-    return (BindingType)(m_nextBindingPtr & 0x3);
+    m_nextBinding = b;
 }
 
 QT_END_NAMESPACE
diff --git a/src/qml/qml/qqmlbinding.cpp b/src/qml/qml/qqmlbinding.cpp
index 3cd6707cf2..317c4172d7 100644
--- a/src/qml/qml/qqmlbinding.cpp
+++ b/src/qml/qml/qqmlbinding.cpp
@@ -54,7 +54,7 @@ QQmlBinding::Identifier QQmlBinding::Invalid = -1;
 
 QQmlBinding::QQmlBinding(const QString &str, QObject *obj, QQmlContext *ctxt)
     : QQmlJavaScriptExpression(),
-      QQmlAbstractBinding(Binding)
+      QQmlAbstractBinding()
 {
     setNotifyOnValueChanged(true);
     QQmlJavaScriptExpression::setContext(QQmlContextData::get(ctxt));
@@ -66,7 +66,7 @@ QQmlBinding::QQmlBinding(const QString &str, QObject *obj, QQmlContext *ctxt)
 
 QQmlBinding::QQmlBinding(const QQmlScriptString &script, QObject *obj, QQmlContext *ctxt)
     : QQmlJavaScriptExpression(),
-      QQmlAbstractBinding(Binding)
+      QQmlAbstractBinding()
 {
     if (ctxt && !ctxt->isValid())
         return;
@@ -101,7 +101,7 @@ QQmlBinding::QQmlBinding(const QQmlScriptString &script, QObject *obj, QQmlConte
 
 QQmlBinding::QQmlBinding(const QString &str, QObject *obj, QQmlContextData *ctxt)
     : QQmlJavaScriptExpression(),
-      QQmlAbstractBinding(Binding)
+      QQmlAbstractBinding()
 {
     setNotifyOnValueChanged(true);
     QQmlJavaScriptExpression::setContext(ctxt);
@@ -115,7 +115,7 @@ QQmlBinding::QQmlBinding(const QString &str, QObject *obj,
                          QQmlContextData *ctxt,
                          const QString &url, quint16 lineNumber, quint16 columnNumber)
     : QQmlJavaScriptExpression(),
-      QQmlAbstractBinding(Binding)
+      QQmlAbstractBinding()
 {
     Q_UNUSED(columnNumber);
     setNotifyOnValueChanged(true);
@@ -128,7 +128,7 @@ QQmlBinding::QQmlBinding(const QString &str, QObject *obj,
 
 QQmlBinding::QQmlBinding(const QV4::Value &functionPtr, QObject *obj, QQmlContextData *ctxt)
     : QQmlJavaScriptExpression(),
-      QQmlAbstractBinding(Binding)
+      QQmlAbstractBinding()
 {
     setNotifyOnValueChanged(true);
     QQmlJavaScriptExpression::setContext(ctxt);
diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index 38268528c9..02618549d3 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -654,7 +654,7 @@ void QQmlObjectCreator::setupBindings(const QBitArray &bindingsToSkip)
     if (_valueTypeProperty) {
         QQmlAbstractBinding *binding = QQmlPropertyPrivate::binding(_bindingTarget, _valueTypeProperty->coreIndex);
 
-        if (binding && binding->bindingType() != QQmlAbstractBinding::ValueTypeProxy) {
+        if (binding && !binding->isValueTypeProxy()) {
             QQmlPropertyPrivate::removeBinding(_bindingTarget, _valueTypeProperty->coreIndex, QQmlPropertyPrivate::DestroyOldBinding);
         } else if (binding) {
             QQmlValueTypeProxyBinding *proxy = static_cast<QQmlValueTypeProxyBinding *>(binding);
diff --git a/src/qml/qml/qqmlproperty.cpp b/src/qml/qml/qqmlproperty.cpp
index 39af82f0eb..997859d410 100644
--- a/src/qml/qml/qqmlproperty.cpp
+++ b/src/qml/qml/qqmlproperty.cpp
@@ -749,7 +749,7 @@ static QQmlAbstractBinding *removeOldBinding(QObject *object, int index, QQmlPro
     if (!oldBinding)
         return 0;
 
-    if (valueTypeIndex != -1 && oldBinding->bindingType() == QQmlAbstractBinding::ValueTypeProxy)
+    if (valueTypeIndex != -1 && oldBinding->isValueTypeProxy())
         oldBinding = static_cast<QQmlValueTypeProxyBinding *>(oldBinding)->binding(index);
 
     if (!oldBinding)
@@ -810,7 +810,7 @@ QQmlPropertyPrivate::binding(QObject *object, int index)
         binding = binding->nextBinding();
 
     if (binding && valueTypeIndex != -1) {
-        if (binding->bindingType() == QQmlAbstractBinding::ValueTypeProxy) {
+        if (binding->isValueTypeProxy()) {
             int index = QQmlPropertyData::encodeValueTypePropertyIndex(coreIndex, valueTypeIndex);
             binding = static_cast<QQmlValueTypeProxyBinding *>(binding)->binding(index);
         }
diff --git a/src/qml/qml/qqmlvaluetypeproxybinding.cpp b/src/qml/qml/qqmlvaluetypeproxybinding.cpp
index bf6a7d6045..0c8dd04910 100644
--- a/src/qml/qml/qqmlvaluetypeproxybinding.cpp
+++ b/src/qml/qml/qqmlvaluetypeproxybinding.cpp
@@ -36,7 +36,7 @@
 QT_BEGIN_NAMESPACE
 
 QQmlValueTypeProxyBinding::QQmlValueTypeProxyBinding(QObject *o, int index)
-    : QQmlAbstractBinding(ValueTypeProxy),
+    : QQmlAbstractBinding(),
       m_bindings(0)
 {
     m_target = o;
@@ -65,6 +65,11 @@ void QQmlValueTypeProxyBinding::setEnabled(bool e, QQmlPropertyPrivate::WriteFla
     }
 }
 
+bool QQmlValueTypeProxyBinding::isValueTypeProxy() const
+{
+    return true;
+}
+
 QQmlAbstractBinding *QQmlValueTypeProxyBinding::binding(int propertyIndex)
 {
     QQmlAbstractBinding *binding = m_bindings;
diff --git a/src/qml/qml/qqmlvaluetypeproxybinding_p.h b/src/qml/qml/qqmlvaluetypeproxybinding_p.h
index f6d9c0abc1..7ddd5c1d93 100644
--- a/src/qml/qml/qqmlvaluetypeproxybinding_p.h
+++ b/src/qml/qml/qqmlvaluetypeproxybinding_p.h
@@ -58,6 +58,7 @@ public:
     void removeBindings(quint32 mask);
 
     virtual void setEnabled(bool, QQmlPropertyPrivate::WriteFlags);
+    virtual bool isValueTypeProxy() const;
 
 protected:
     ~QQmlValueTypeProxyBinding();