implement ability to dynamically change class of script objects

With an object created by QScriptEngine::newObject(), it should
be possible to call QScriptValue::setClass() to dynamically
change the behavior of that object. Similarly, it should be
possible to promote plain script objects to QObject (QVariant)
wrappers by calling the overload of QScriptEngine::newQObject()
(newVariant()) that takes a script object as the first argument.
This commit implements this capability.

The premise is the (internal) QScriptObject class, which inherits
JSC::JSObject. It reimplements all the methods for getting/setting
properties etc. Then there's a level of indirection to facilitate
dynamic change of the class: Each QScriptObject can have a
delegate associated with it that will handle operations on the
object. By default there is no delegate, so the object behaves as
a normal JS object, as you expect. However, once a delegate is set
(e.g., when QScriptValue::setScriptClass() is called),
QScriptObject will give the delegate the chance to handle the
object operation.

In addition to a delegate implementation for QScriptClass-based
objects, there are also delegates for QObject and QVariant
wrappers. These replace the QObjectWrapperObject and
QVariantWrapperObject classes.

1 files changed, 84 insertions, 0 deletions

diff --git a/src/script/bridge/qscriptclassobject_p.h b/src/script/bridge/qscriptclassobject_p.h
new file mode 100644
index 0000000..b2d6d7f
--- /dev/null
+++ b/src/script/bridge/qscriptclassobject_p.h
@@ -0,0 +1,84 @@
+/****************************************************************************
+**
+** Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the $MODULE$ of the Qt Toolkit.
+**
+** $TROLLTECH_DUAL_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QSCRIPTCLASSOBJECT_P_H
+#define QSCRIPTCLASSOBJECT_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtCore/qobjectdefs.h>
+
+#ifndef QT_NO_SCRIPT
+
+#include "qscriptobject_p.h"
+
+QT_BEGIN_NAMESPACE
+
+class QScriptClass;
+
+namespace QScript
+{
+
+class ClassObjectDelegate : public QScriptObjectDelegate
+{
+public:
+    ClassObjectDelegate(QScriptClass *scriptClass);
+    ~ClassObjectDelegate();
+
+    QScriptClass *scriptClass() const;
+    void setScriptClass(QScriptClass *scriptClass);
+
+    virtual Type type() const;
+
+    virtual bool getOwnPropertySlot(QScriptObject*, JSC::ExecState*,
+                                    const JSC::Identifier& propertyName,
+                                    JSC::PropertySlot&);
+    virtual void put(QScriptObject*, JSC::ExecState* exec,
+                     const JSC::Identifier& propertyName,
+                     JSC::JSValue, JSC::PutPropertySlot&);
+    virtual bool deleteProperty(QScriptObject*, JSC::ExecState*,
+                                const JSC::Identifier& propertyName);
+    virtual bool getPropertyAttributes(const QScriptObject*, JSC::ExecState*,
+                                       const JSC::Identifier&,
+                                       unsigned&) const;
+    virtual void getPropertyNames(QScriptObject*, JSC::ExecState*,
+                                  JSC::PropertyNameArray&);
+
+    virtual JSC::CallType getCallData(QScriptObject*, JSC::CallData&);
+    static JSC::JSValue JSC_HOST_CALL call(JSC::ExecState*, JSC::JSObject*,
+                                           JSC::JSValue, const JSC::ArgList&);
+    virtual JSC::ConstructType getConstructData(QScriptObject*, JSC::ConstructData&);
+    static JSC::JSObject* construct(JSC::ExecState*, JSC::JSObject*,
+                                    const JSC::ArgList&);
+
+    virtual bool hasInstance(QScriptObject*, JSC::ExecState*,
+                             JSC::JSValue value, JSC::JSValue proto);
+
+private:
+    QScriptClass *m_scriptClass;
+};
+
+} // namespace QScript
+
+QT_END_NAMESPACE
+
+#endif // QT_NO_SCRIPT
+
+#endif