Abstract expression and binding APIs

By splitting the interface through which the system interacts with bindings
away from a specific implementation, we can introduce highly specialized
implementations for specific optimizations.

This commit also includes a sample optimization for object properties being
assigned directly from a local id.

1 files changed, 19 insertions, 6 deletions

diff --git a/src/declarative/qml/qmlexpression_p.h b/src/declarative/qml/qmlexpression_p.h
index bf95c0e0..997bf8d 100644
--- a/src/declarative/qml/qmlexpression_p.h
+++ b/src/declarative/qml/qmlexpression_p.h
@@ -61,19 +61,33 @@
 
 QT_BEGIN_NAMESPACE
 
+class QmlAbstractExpression
+{
+public:
+    QmlAbstractExpression();
+    virtual ~QmlAbstractExpression();
+
+    bool isValid() const;
+
+    QmlContext *context() const;
+    void setContext(QmlContext *);
+
+private:
+    friend class QmlContext;
+    QmlContext *m_context;
+    QmlAbstractExpression **m_prevExpression;
+    QmlAbstractExpression  *m_nextExpression;
+};
+
 class QmlExpression;
 class QString;
-class QmlExpressionPrivate : public QObjectPrivate
+class QmlExpressionPrivate : public QObjectPrivate, public QmlAbstractExpression
 {
     Q_DECLARE_PUBLIC(QmlExpression)
 public:
     QmlExpressionPrivate();
     ~QmlExpressionPrivate();
 
-    // Forms the QmlContext "expressions" linked list
-    QmlExpressionPrivate *nextExpression;
-    QmlExpressionPrivate **prevExpression;
-
     enum CompiledDataType {
         BasicScriptEngineData = 1,
         PreTransformedQtScriptData = 2
@@ -82,7 +96,6 @@ public:
     void init(QmlContext *, const QString &, QObject *);
     void init(QmlContext *, void *, QmlRefCount *, QObject *);
 
-    QmlContext *ctxt;
     QString expression;
     bool expressionFunctionValid:1;
     bool expressionRewritten:1;