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Remove QPropertyMemberChangeHandler again

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Adding support for a static notifier within QProperty itself - through a
QProperty "sister" class - is more efficient in terms of memory
consumption and run-time performance.

The MemberChangeHandler permanently takes up at least three pointers,
while the notified properties only cost one pointer in the binding.

Change-Id: Ia1a8c2b66f1f3c2fe13ae0ad9f12cdb6bdcc35ef
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
This commit is contained in:
Simon Hausmann 2020-04-30 08:34:42 +02:00 committed by Fabian Kosmale
parent e18a060c03
commit b20c7df63a
2 changed files with 0 additions and 43 deletions
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23
src/corelib/kernel/qproperty.h
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@ -731,28 +731,6 @@ QPropertyChangeHandler<Functor> QNotifiedProperty<T, Callback, ValueGuard>::subs
return onValueChanged(f);
}
template <auto propertyMember, auto callbackMember>
struct QPropertyMemberChangeHandler;
template<typename Class, typename PropertyType, PropertyType Class::* PropertyMember, void(Class::*Callback)()>
struct QPropertyMemberChangeHandler<PropertyMember, Callback> : public QPropertyObserver
{
QPropertyMemberChangeHandler(Class *obj)
: QPropertyObserver(notify)
{
setSource(obj->*PropertyMember);
}
static void notify(QPropertyObserver *, void *propertyDataPtr)
{
// memberOffset is the offset of the QProperty<> member within the class. We get the absolute address
// of that member and subtracting the relative offset gives us the address of the class instance.
const size_t memberOffset = reinterpret_cast<size_t>(&(static_cast<Class *>(nullptr)->*PropertyMember));
Class *obj = reinterpret_cast<Class *>(reinterpret_cast<char *>(propertyDataPtr) - memberOffset);
(obj->*Callback)();
}
};
template<typename T>
class QPropertyAlias : public QPropertyObserver
{
@ -892,7 +870,6 @@ public:
return aliasedProperty<T>() != nullptr;
}
};
QT_END_NAMESPACE
#endif // QPROPERTY_H

20
tests/auto/corelib/kernel/qproperty/tst_qproperty.cpp
View File

@ -67,7 +67,6 @@ private slots:
void settingPropertyValueDoesRemoveBinding();
void genericPropertyBinding();
void genericPropertyBindingBool();
void staticChangeHandler();
void setBindingFunctor();
void multipleObservers();
void propertyAlias();
@ -661,25 +660,6 @@ void tst_QProperty::genericPropertyBindingBool()
QVERIFY(property.value());
}
struct ItemType
{
QProperty<int> x;
QVector<int> observedValues;
void xChanged() {
observedValues << x.value();
}
QPropertyMemberChangeHandler<&ItemType::x, &ItemType::xChanged> test{this};
};
void tst_QProperty::staticChangeHandler()
{
ItemType t;
t.x = 42;
t.x = 100;
QVector<int> values{42, 100};
QCOMPARE(t.observedValues, values);
}
void tst_QProperty::setBindingFunctor()
{
QProperty<int> property;