Introduce a new mechanism to iterate over object properties

The old advanceIterator schema was extremely ugly and in addition
not flexible enough to support the requirements for Proxy.ownKeys
and some of the methods in Object

Implemented a new scheme through a OwnPropertyKeys method in the
Object VTable that creates and returns an iterator object. Ported
QJSValueIterator and for-in to use the new mechanism.

There's still many places where we use the old ObjectIterator (that
relies on advanceIterator). Those will be ported in subsequent
commits.

Change-Id: I091a9bea9ff6b2b63630cc336814700757a718be
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/qml/jsruntime/qv4vtable_p.h b/src/qml/jsruntime/qv4vtable_p.h
index b4e868d45d..aff8eb83ac 100644
--- a/src/qml/jsruntime/qv4vtable_p.h
+++ b/src/qml/jsruntime/qv4vtable_p.h
@@ -56,6 +56,11 @@ QT_BEGIN_NAMESPACE
 
 namespace QV4 {
 
+struct OwnPropertyKeyIterator {
+    virtual ~OwnPropertyKeyIterator() = 0;
+    virtual PropertyKey next(const Object *o, Property *p = nullptr, PropertyAttributes *attrs = nullptr) = 0;
+};
+
 struct VTable
 {
     typedef void (*Destroy)(Heap::Base *);
@@ -74,6 +79,7 @@ struct VTable
     typedef bool (*SetPrototypeOf)(Managed *, const Object *);
     typedef qint64 (*GetLength)(const Managed *m);
     typedef void (*AdvanceIterator)(Managed *m, ObjectIterator *it, Value *name, uint *index, Property *p, PropertyAttributes *attributes);
+    typedef OwnPropertyKeyIterator *(*OwnPropertyKeys)(const Object *m);
     typedef ReturnedValue (*InstanceOf)(const Object *typeObject, const Value &var);
 
     typedef ReturnedValue (*Call)(const FunctionObject *, const Value *thisObject, const Value *argv, int argc);
@@ -109,6 +115,7 @@ struct VTable
     SetPrototypeOf setPrototypeOf;
     GetLength getLength;
     AdvanceIterator advanceIterator;
+    OwnPropertyKeys ownPropertyKeys;
     InstanceOf instanceOf;
 
     Call call;
@@ -133,6 +140,7 @@ protected:
     static constexpr VTable::SetPrototypeOf virtualSetPrototypeOf = nullptr;
     static constexpr VTable::GetLength virtualGetLength = nullptr;
     static constexpr VTable::AdvanceIterator virtualAdvanceIterator = nullptr;
+    static constexpr VTable::OwnPropertyKeys virtualOwnPropertyKeys = nullptr;
     static constexpr VTable::InstanceOf virtualInstanceOf = nullptr;
 
     static constexpr VTable::Call virtualCall = nullptr;
@@ -172,6 +180,7 @@ protected:
     classname::virtualSetPrototypeOf,       \
     classname::virtualGetLength,            \
     classname::virtualAdvanceIterator,      \
+    classname::virtualOwnPropertyKeys,      \
     classname::virtualInstanceOf,           \
     \
     classname::virtualCall,                 \