Enable lookups in QML

The main feature that needs to be implemented in order to enable lookups
in QML files is to respect that the QObject wrapper has its own storage
layer (meta-object properties). Lookups need to be able to index those
when the base is a QObject. This is done by caching the property data
and guarding the validity by comparing property cache pointers.

The same lookup logic is also implemented for value type wrappers.

OVerall there's more that can be done with lookups in meta-objects, for
constant properties for example.

For "global" lookups we have a safeguard in place that generates a
LoadName instruction for property access that should end up in the qml
context wrapper. So no changes are needed here at first, but the lookup
in the QML context can be optimized in the future.

The way of storing the property cache in the lookup itself trades
ugliness on destruction against the creation of less internal classes.
Another option would be to store the property cache in the internal
class and let QObjectWrapper always transition via the property cache.

Task-number: QTBUG-69898
Change-Id: I9c378c071acc6d7d4a34a2a76616f9594119d515
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 6 insertions, 1 deletions

diff --git a/src/qml/jsruntime/qv4qobjectwrapper_p.h b/src/qml/jsruntime/qv4qobjectwrapper_p.h
index 6465ee0fa6..a09e7b6e95 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper_p.h
+++ b/src/qml/jsruntime/qv4qobjectwrapper_p.h
@@ -183,6 +183,11 @@ struct Q_QML_EXPORT QObjectWrapper : public Object
     void destroyObject(bool lastCall);
 
     static ReturnedValue getProperty(ExecutionEngine *engine, QObject *object, QQmlPropertyData *property, bool captureRequired = true);
+
+    static ReturnedValue virtualResolveLookupGetter(const Object *object, ExecutionEngine *engine, Lookup *lookup);
+    static ReturnedValue lookupGetter(Lookup *l, ExecutionEngine *engine, const Value &object);
+    static bool virtualResolveLookupSetter(Object *object, ExecutionEngine *engine, Lookup *lookup, const Value &value);
+
 protected:
     static void setProperty(ExecutionEngine *engine, QObject *object, QQmlPropertyData *property, const Value &value);
 
@@ -228,7 +233,7 @@ struct Q_QML_EXPORT QObjectMethod : public QV4::FunctionObject
     enum { DestroyMethod = -1, ToStringMethod = -2 };
 
     static ReturnedValue create(QV4::ExecutionContext *scope, QObject *object, int index);
-    static ReturnedValue create(QV4::ExecutionContext *scope, const QQmlValueTypeWrapper *valueType, int index);
+    static ReturnedValue create(QV4::ExecutionContext *scope, Heap::QQmlValueTypeWrapper *valueType, int index);
 
     int methodIndex() const { return d()->index; }
     QObject *object() const { return d()->object(); }