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QNotifiedProperty: pass old value to callback if requested

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Check at compile time whether the static callback takes an argument
(which has to be of the same time as the type of the property). If so,
retrieve the old value and pass it to the callback.

Change-Id: Ib1c4c9e05b826b6be492b03f66fa72ad015963ee
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
This commit is contained in:
Fabian Kosmale 2020-06-18 16:55:48 +02:00
parent c2fb27f054
commit 6a24ac7c4e
6 changed files with 110 additions and 30 deletions
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2
src/corelib/kernel/qproperty.cpp
View File

@ -95,7 +95,7 @@ QPropertyBase::~QPropertyBase()
QUntypedPropertyBinding QPropertyBase::setBinding(const QUntypedPropertyBinding &binding,
void *propertyDataPtr,
void *staticObserver,
void (*staticObserverCallback)(void*))
void (*staticObserverCallback)(void*, void*))
{
QPropertyBindingPrivatePtr oldBinding;
QPropertyBindingPrivatePtr newBinding = binding.d;

99
src/corelib/kernel/qproperty.h
View File

@ -374,11 +374,21 @@ namespace Qt {
}
}
template <typename T, typename Class, void(Class::*Callback)()>
class QNotifiedProperty<T, Callback>
namespace detail {
template <typename F>
struct ExtractClassFromFunctionPointer;
template<typename T, typename C>
struct ExtractClassFromFunctionPointer<T C::*> { using Class = C; };
}
template <typename T, auto Callback>
class QNotifiedProperty
{
public:
using value_type = T;
using Class = typename detail::ExtractClassFromFunctionPointer<decltype(Callback)>::Class;
static_assert(std::is_invocable_v<decltype(Callback), Class, T> || std::is_invocable_v<decltype(Callback), Class>);
QNotifiedProperty() = default;
@ -420,45 +430,83 @@ public:
void setValue(Class *owner, T &&newValue)
{
if (d.setValueAndReturnTrueIfChanged(std::move(newValue)))
notify(owner);
if constexpr(std::is_invocable_v<decltype(Callback), Class>) {
if (d.setValueAndReturnTrueIfChanged(std::move(newValue)))
notify(owner);
} else {
T oldValue = value(); // TODO: kind of pointless if there was no change
if (d.setValueAndReturnTrueIfChanged(std::move(newValue)))
notify(owner, &oldValue);
}
d.priv.removeBinding();
}
void setValue(Class *owner, const T &newValue)
{
if (d.setValueAndReturnTrueIfChanged(newValue))
notify(owner);
if constexpr(std::is_invocable_v<decltype(Callback), Class>) {
if (d.setValueAndReturnTrueIfChanged(newValue))
notify(owner);
} else {
T oldValue = value();
if (d.setValueAndReturnTrueIfChanged(newValue))
notify(owner, &oldValue);
}
d.priv.removeBinding();
}
QPropertyBinding<T> setBinding(Class *owner, const QPropertyBinding<T> &newBinding)
{
QPropertyBinding<T> oldBinding(d.priv.setBinding(newBinding, &d, owner, [](void *o) {
(reinterpret_cast<Class *>(o)->*Callback)();
}));
notify(owner);
return oldBinding;
if constexpr(std::is_invocable_v<decltype(Callback), Class>) {
QPropertyBinding<T> oldBinding(d.priv.setBinding(newBinding, &d, owner, [](void *o) {
(reinterpret_cast<Class *>(o)->*Callback)();
}));
notify(owner);
return oldBinding;
} else {
T oldValue = value();
QPropertyBinding<T> oldBinding(d.priv.setBinding(newBinding, &d, owner, [](void *o, void *oldValue) {
(reinterpret_cast<Class *>(o)->*Callback)(*reinterpret_cast<T *>(oldValue));
}));
notify(owner, &oldValue);
return oldBinding;
}
}
QPropertyBinding<T> setBinding(Class *owner, QPropertyBinding<T> &&newBinding)
{
QPropertyBinding<T> b(std::move(newBinding));
QPropertyBinding<T> oldBinding(d.priv.setBinding(b, &d, owner, [](void *o) {
(reinterpret_cast<Class *>(o)->*Callback)();
}));
notify(owner);
return oldBinding;
if constexpr(std::is_invocable_v<decltype(Callback), Class>) {
QPropertyBinding<T> oldBinding(d.priv.setBinding(b, &d, owner, [](void *o, void *) {
(reinterpret_cast<Class *>(o)->*Callback)();
}));
notify(owner);
return oldBinding;
} else {
T oldValue = value();
QPropertyBinding<T> oldBinding(d.priv.setBinding(b, &d, owner, [](void *o, void *oldValue) {
(reinterpret_cast<Class *>(o)->*Callback)(*reinterpret_cast<T *>(oldValue));
}));
notify(owner, &oldValue);
return oldBinding;
}
}
bool setBinding(Class *owner, const QUntypedPropertyBinding &newBinding)
{
if (newBinding.valueMetaType().id() != qMetaTypeId<T>())
return false;
d.priv.setBinding(newBinding, &d, owner, [](void *o) {
(reinterpret_cast<Class *>(o)->*Callback)();
});
notify(owner);
if constexpr(std::is_invocable_v<decltype(Callback), Class>) {
d.priv.setBinding(newBinding, &d, owner, [](void *o, void *) {
(reinterpret_cast<Class *>(o)->*Callback)();
});
notify(owner);
} else {
T oldValue = value();
d.priv.setBinding(newBinding, &d, owner, [](void *o, void *oldValue) {
(reinterpret_cast<Class *>(o)->*Callback)(*reinterpret_cast<T *>(oldValue));
});
notify(owner, &oldValue);
}
return true;
}
@ -493,10 +541,13 @@ public:
QPropertyChangeHandler<Functor> subscribe(Functor f);
private:
void notify(Class *owner)
void notify(Class *owner, T *oldValue=nullptr)
{
d.priv.notifyObservers(&d);
(owner->*Callback)();
if constexpr(std::is_invocable_v<decltype(Callback), Class>)
(owner->*Callback)();
else
(owner->*Callback)(*oldValue);
}
Q_DISABLE_COPY_MOVE(QNotifiedProperty)
@ -624,7 +675,7 @@ QPropertyChangeHandler<Functor> QProperty<T>::subscribe(Functor f)
return onValueChanged(f);
}
template <typename T, typename Class, void(Class::*Callback)()>
template <typename T, auto Callback>
template<typename Functor>
QPropertyChangeHandler<Functor> QNotifiedProperty<T, Callback>::onValueChanged(Functor f)
{
@ -634,7 +685,7 @@ QPropertyChangeHandler<Functor> QNotifiedProperty<T, Callback>::onValueChanged(F
return QPropertyChangeHandler<Functor>(*this, f);
}
template <typename T, typename Class, void(Class::*Callback)()>
template <typename T, auto Callback>
template<typename Functor>
QPropertyChangeHandler<Functor> QNotifiedProperty<T, Callback>::subscribe(Functor f)
{

11
src/corelib/kernel/qpropertybinding.cpp
View File

@ -69,8 +69,15 @@ void QPropertyBindingPrivate::markDirtyAndNotifyObservers()
dirty = true;
if (firstObserver)
firstObserver.notify(this, propertyDataPtr);
if (hasStaticObserver)
staticObserverCallback(staticObserver);
if (hasStaticObserver) {
if (metaType == QMetaType::fromType<bool>()) {
auto propertyPtr = reinterpret_cast<QPropertyBase *>(propertyDataPtr);
bool oldValue = propertyPtr->extraBit();
staticObserverCallback(staticObserver, &oldValue);
} else {
staticObserverCallback(staticObserver, propertyDataPtr);
}
}
}
bool QPropertyBindingPrivate::evaluateIfDirtyAndReturnTrueIfValueChanged()

4
src/corelib/kernel/qpropertybinding_p.h
View File

@ -80,7 +80,7 @@ private:
ObserverArray inlineDependencyObservers;
struct {
void *staticObserver;
void (*staticObserverCallback)(void*);
void (*staticObserverCallback)(void*, void*);
};
};
QScopedPointer<std::vector<QPropertyObserver>> heapObservers;
@ -107,7 +107,7 @@ public:
void setDirty(bool d) { dirty = d; }
void setProperty(void *propertyPtr) { propertyDataPtr = propertyPtr; }
void setStaticObserver(void *observer, void (*callback)(void*))
void setStaticObserver(void *observer, void (*callback)(void*, void*))
{
if (observer) {
if (!hasStaticObserver) {

2
src/corelib/kernel/qpropertyprivate.h
View File

@ -84,7 +84,7 @@ public:
QUntypedPropertyBinding setBinding(const QUntypedPropertyBinding &newBinding,
void *propertyDataPtr, void *staticObserver = nullptr,
void (*staticObserverCallback)(void*) = nullptr);
void (*staticObserverCallback)(void *, void *) = nullptr);
QPropertyBindingPrivate *binding();
void evaluateIfDirty();

22
tests/auto/corelib/kernel/qproperty/tst_qproperty.cpp
View File

@ -72,6 +72,7 @@ private slots:
void multipleObservers();
void propertyAlias();
void notifiedProperty();
void notifiedPropertyWithOldValueCallback();
};
void tst_QProperty::functorBinding()
@ -779,6 +780,15 @@ struct ClassWithNotifiedProperty
QNotifiedProperty<int, &ClassWithNotifiedProperty::callback> property;
};
struct ClassWithNotifiedProperty2
{
QVector<int> recordedValues;
void callback(int oldValue) { recordedValues << oldValue; }
QNotifiedProperty<int, &ClassWithNotifiedProperty2::callback> property;
};
void tst_QProperty::notifiedProperty()
{
ClassWithNotifiedProperty instance;
@ -854,6 +864,18 @@ void tst_QProperty::notifiedProperty()
QCOMPARE(subscribedCount, 10);
}
void tst_QProperty::notifiedPropertyWithOldValueCallback()
{
ClassWithNotifiedProperty2 instance;
instance.property.setValue(&instance, 1);
instance.property.setBinding(&instance, [](){return 2;});
instance.property.setBinding(&instance, [](){return 3;});
instance.property.setValue(&instance, 4);
QVector<int> expected {0, 1, 2, 3};
QCOMPARE(instance.recordedValues, expected);
QCOMPARE(instance.property.value(), 4);
}
QTEST_MAIN(tst_QProperty);
#include "tst_qproperty.moc"