/*************************************************************************** ** ** Copyright (C) 2020 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the QtCore module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 3 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL3 included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 3 requirements ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU ** General Public License version 2.0 or (at your option) the GNU General ** Public license version 3 or any later version approved by the KDE Free ** Qt Foundation. The licenses are as published by the Free Software ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 ** included in the packaging of this file. Please review the following ** information to ensure the GNU General Public License requirements will ** be met: https://www.gnu.org/licenses/gpl-2.0.html and ** https://www.gnu.org/licenses/gpl-3.0.html. ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #ifndef QPROPERTY_P_H #define QPROPERTY_P_H // // W A R N I N G // ------------- // // This file is not part of the Qt API. It exists for the convenience // of a number of Qt sources files. This header file may change from // version to version without notice, or even be removed. // // We mean it. // #include #include #include #include #include QT_BEGIN_NAMESPACE namespace QtPrivate { Q_CORE_EXPORT bool isAnyBindingEvaluating(); } // Keep all classes related to QProperty in one compilation unit. Performance of this code is crucial and // we need to allow the compiler to inline where it makes sense. // This is a helper "namespace" struct Q_AUTOTEST_EXPORT QPropertyBindingDataPointer { const QtPrivate::QPropertyBindingData *ptr = nullptr; QPropertyBindingPrivate *binding() const { return ptr->binding(); } void setObservers(QPropertyObserver *observer) { auto &d = ptr->d_ref(); observer->prev = reinterpret_cast(&d); d = reinterpret_cast(observer); } static void fixupAfterMove(QtPrivate::QPropertyBindingData *ptr); void Q_ALWAYS_INLINE addObserver(QPropertyObserver *observer); void setFirstObserver(QPropertyObserver *observer); QPropertyObserverPointer firstObserver() const; int observerCount() const; template static QPropertyBindingDataPointer get(QProperty &property) { return QPropertyBindingDataPointer{&property.bindingData()}; } }; // This is a helper "namespace" struct QPropertyObserverPointer { QPropertyObserver *ptr = nullptr; void unlink(); void unlink_fast(); void setBindingToNotify(QPropertyBindingPrivate *binding); void setBindingToNotify_unsafe(QPropertyBindingPrivate *binding); void setChangeHandler(QPropertyObserver::ChangeHandler changeHandler); void notify(QUntypedPropertyData *propertyDataPtr); #ifndef QT_NO_DEBUG void noSelfDependencies(QPropertyBindingPrivate *binding); #else void noSelfDependencies(QPropertyBindingPrivate *) {} #endif void evaluateBindings(QBindingStatus *status); void observeProperty(QPropertyBindingDataPointer property); explicit operator bool() const { return ptr != nullptr; } QPropertyObserverPointer nextObserver() const { return {ptr->next.data()}; } }; class QPropertyBindingErrorPrivate : public QSharedData { public: QPropertyBindingError::Type type = QPropertyBindingError::NoError; QString description; }; namespace QtPrivate { struct BindingEvaluationState { BindingEvaluationState(QPropertyBindingPrivate *binding, QBindingStatus *status); ~BindingEvaluationState() { *currentState = previousState; } QPropertyBindingPrivate *binding; BindingEvaluationState *previousState = nullptr; BindingEvaluationState **currentState = nullptr; }; /*! * \internal * CompatPropertySafePoint needs to be constructed before the setter of * a QObjectCompatProperty runs. It prevents spurious binding dependencies * caused by reads of properties inside the compat property setter. * Moreover, it ensures that we don't destroy bindings when using operator= */ struct CompatPropertySafePoint { Q_CORE_EXPORT CompatPropertySafePoint(QBindingStatus *status, QUntypedPropertyData *property); ~CompatPropertySafePoint() { *currentState = previousState; *currentlyEvaluatingBindingList = bindingState; } QUntypedPropertyData *property; CompatPropertySafePoint *previousState = nullptr; CompatPropertySafePoint **currentState = nullptr; QtPrivate::BindingEvaluationState **currentlyEvaluatingBindingList = nullptr; QtPrivate::BindingEvaluationState *bindingState = nullptr; }; } class Q_CORE_EXPORT QPropertyBindingPrivate : public QtPrivate::RefCounted { private: friend struct QPropertyBindingDataPointer; friend class QPropertyBindingPrivatePtr; using ObserverArray = std::array; private: // used to detect binding loops for lazy evaluated properties bool updating = false; bool hasStaticObserver = false; bool pendingNotify = false; bool hasBindingWrapper:1; // used to detect binding loops for eagerly evaluated properties bool isQQmlPropertyBinding:1; /* a sticky binding does not get removed in removeBinding this is used to support QQmlPropertyData::DontRemoveBinding in qtdeclarative */ bool m_sticky:1; const QtPrivate::BindingFunctionVTable *vtable; union { QtPrivate::QPropertyObserverCallback staticObserverCallback = nullptr; QtPrivate::QPropertyBindingWrapper staticBindingWrapper; }; ObserverArray inlineDependencyObservers; // for things we are observing QPropertyObserverPointer firstObserver; // list of observers observing us QScopedPointer> heapObservers; // for things we are observing protected: QUntypedPropertyData *propertyDataPtr = nullptr; /* For bindings set up from C++, location stores where the binding was created in the C++ source For QQmlPropertyBinding that information does not make sense, and the location in the QML file is stored somewhere else. To make efficient use of the space, we instead provide a scratch space for QQmlPropertyBinding (which stores further binding information there). Anything stored in the union must be trivially destructible. */ static_assert(std::is_trivially_destructible_v); static_assert(std::is_trivially_destructible_v); using DeclarativeErrorCallback = void(*)(QPropertyBindingPrivate *); union { QPropertyBindingSourceLocation location; struct { std::byte declarativeExtraData[sizeof(QPropertyBindingSourceLocation) - sizeof(DeclarativeErrorCallback)]; DeclarativeErrorCallback errorCallBack; }; }; private: QPropertyBindingError error; QMetaType metaType; public: static constexpr size_t getSizeEnsuringAlignment() { constexpr auto align = alignof (std::max_align_t) - 1; constexpr size_t sizeEnsuringAlignment = (sizeof(QPropertyBindingPrivate) + align) & ~align; static_assert (sizeEnsuringAlignment % alignof (std::max_align_t) == 0, "Required for placement new'ing the function behind it."); return sizeEnsuringAlignment; } // public because the auto-tests access it, too. size_t dependencyObserverCount = 0; bool isUpdating() {return updating;} void setSticky(bool keep = true) {m_sticky = keep;} bool isSticky() {return m_sticky;} QPropertyBindingPrivate(QMetaType metaType, const QtPrivate::BindingFunctionVTable *vtable, const QPropertyBindingSourceLocation &location, bool isQQmlPropertyBinding=false) : hasBindingWrapper(false) , isQQmlPropertyBinding(isQQmlPropertyBinding) , m_sticky(false) , vtable(vtable) , location(location) , metaType(metaType) {} ~QPropertyBindingPrivate(); void setProperty(QUntypedPropertyData *propertyPtr) { propertyDataPtr = propertyPtr; } void setStaticObserver(QtPrivate::QPropertyObserverCallback callback, QtPrivate::QPropertyBindingWrapper bindingWrapper) { Q_ASSERT(!(callback && bindingWrapper)); if (callback) { hasStaticObserver = true; hasBindingWrapper = false; staticObserverCallback = callback; } else if (bindingWrapper) { hasStaticObserver = false; hasBindingWrapper = true; staticBindingWrapper = bindingWrapper; } else { hasStaticObserver = false; hasBindingWrapper = false; staticObserverCallback = nullptr; } } void prependObserver(QPropertyObserverPointer observer) { observer.ptr->prev = const_cast(&firstObserver.ptr); firstObserver = observer; } QPropertyObserverPointer takeObservers() { auto observers = firstObserver; firstObserver.ptr = nullptr; return observers; } void clearDependencyObservers() { for (size_t i = 0; i < qMin(dependencyObserverCount, inlineDependencyObservers.size()); ++i) { QPropertyObserverPointer p{&inlineDependencyObservers[i]}; p.unlink_fast(); } if (heapObservers) heapObservers->clear(); dependencyObserverCount = 0; } Q_ALWAYS_INLINE QPropertyObserverPointer allocateDependencyObserver() { if (dependencyObserverCount < inlineDependencyObservers.size()) { ++dependencyObserverCount; return {&inlineDependencyObservers[dependencyObserverCount - 1]}; } return allocateDependencyObserver_slow(); } Q_NEVER_INLINE QPropertyObserverPointer allocateDependencyObserver_slow() { ++dependencyObserverCount; if (!heapObservers) heapObservers.reset(new std::vector()); return {&heapObservers->emplace_back()}; } QPropertyBindingSourceLocation sourceLocation() const { if (!hasCustomVTable()) return this->location; QPropertyBindingSourceLocation location; constexpr auto msg = "Custom location"; location.fileName = msg; return location; } QPropertyBindingError bindingError() const { return error; } QMetaType valueMetaType() const { return metaType; } void unlinkAndDeref(); void evaluateRecursive(QBindingStatus *status = nullptr); void Q_ALWAYS_INLINE evaluateRecursive_inline(QBindingStatus *status); void notifyRecursive(); static QPropertyBindingPrivate *get(const QUntypedPropertyBinding &binding) { return static_cast(binding.d.data()); } void setError(QPropertyBindingError &&e) { error = std::move(e); } void detachFromProperty() { hasStaticObserver = false; hasBindingWrapper = false; propertyDataPtr = nullptr; clearDependencyObservers(); } static QPropertyBindingPrivate *currentlyEvaluatingBinding(); bool hasCustomVTable() const { return vtable->size == 0; } static void destroyAndFreeMemory(QPropertyBindingPrivate *priv) { if (priv->hasCustomVTable()) { // special hack for QQmlPropertyBinding which has a // different memory layout than normal QPropertyBindings priv->vtable->destroy(priv); } else{ priv->~QPropertyBindingPrivate(); delete[] reinterpret_cast(priv); } } }; inline void QPropertyBindingDataPointer::setFirstObserver(QPropertyObserver *observer) { if (auto *b = binding()) { b->firstObserver.ptr = observer; return; } auto &d = ptr->d_ref(); d = reinterpret_cast(observer); } inline void QPropertyBindingDataPointer::fixupAfterMove(QtPrivate::QPropertyBindingData *ptr) { auto &d = ptr->d_ref(); if (ptr->isNotificationDelayed()) { QPropertyProxyBindingData *proxyData = reinterpret_cast(d & ~QtPrivate::QPropertyBindingData::BindingBit); proxyData->originalBindingData = ptr; } // If QPropertyBindingData has been moved, and it has an observer // we have to adjust the firstObserver's prev pointer to point to // the moved to QPropertyBindingData's d_ptr if (d & QtPrivate::QPropertyBindingData::BindingBit) return; // nothing to do if the observer is stored in the binding if (auto observer = reinterpret_cast(d)) observer->prev = reinterpret_cast(&d); } inline QPropertyObserverPointer QPropertyBindingDataPointer::firstObserver() const { if (auto *b = binding()) return b->firstObserver; return { reinterpret_cast(ptr->d()) }; } namespace QtPrivate { Q_CORE_EXPORT bool isPropertyInBindingWrapper(const QUntypedPropertyData *property); void Q_CORE_EXPORT initBindingStatusThreadId(); } template class QObjectCompatProperty : public QPropertyData { template friend class QtPrivate::QBindableInterfaceForProperty; using ThisType = QObjectCompatProperty; using SignalTakesValue = std::is_invocable; Class *owner() { char *that = reinterpret_cast(this); return reinterpret_cast(that - QtPrivate::detail::getOffset(Offset)); } const Class *owner() const { char *that = const_cast(reinterpret_cast(this)); return reinterpret_cast(that - QtPrivate::detail::getOffset(Offset)); } static bool bindingWrapper(QMetaType type, QUntypedPropertyData *dataPtr, QtPrivate::QPropertyBindingFunction binding) { auto *thisData = static_cast(dataPtr); QPropertyData copy; binding.vtable->call(type, ©, binding.functor); if constexpr (QTypeTraits::has_operator_equal_v) if (copy.valueBypassingBindings() == thisData->valueBypassingBindings()) return false; // ensure value and setValue know we're currently evaluating our binding QBindingStorage *storage = qGetBindingStorage(thisData->owner()); QtPrivate::CompatPropertySafePoint guardThis(storage->bindingStatus, thisData); (thisData->owner()->*Setter)(copy.valueBypassingBindings()); return true; } bool inBindingWrapper(const QBindingStorage *storage) const { return storage->bindingStatus->currentCompatProperty && QtPrivate::isPropertyInBindingWrapper(this); } public: using value_type = typename QPropertyData::value_type; using parameter_type = typename QPropertyData::parameter_type; using arrow_operator_result = typename QPropertyData::arrow_operator_result; QObjectCompatProperty() = default; explicit QObjectCompatProperty(const T &initialValue) : QPropertyData(initialValue) {} explicit QObjectCompatProperty(T &&initialValue) : QPropertyData(std::move(initialValue)) {} parameter_type value() const { const QBindingStorage *storage = qGetBindingStorage(owner()); // make sure we don't register this binding as a dependency to itself if (!inBindingWrapper(storage)) storage->registerDependency(this); return this->val; } arrow_operator_result operator->() const { if constexpr (QTypeTraits::is_dereferenceable_v) { return value(); } else if constexpr (std::is_pointer_v) { value(); return this->val; } else { return; } } parameter_type operator*() const { return value(); } operator parameter_type() const { return value(); } void setValue(parameter_type t) { QBindingStorage *storage = qGetBindingStorage(owner()); auto *bd = storage->bindingData(this); // make sure we don't remove the binding if called from the bindingWrapper const bool inWrapper = inBindingWrapper(storage); if (bd && !inWrapper) bd->removeBinding(); this->val = t; } QObjectCompatProperty &operator=(parameter_type newValue) { setValue(newValue); return *this; } QPropertyBinding setBinding(const QPropertyBinding &newBinding) { QtPrivate::QPropertyBindingData *bd = qGetBindingStorage(owner())->bindingData(this, true); QUntypedPropertyBinding oldBinding(bd->setBinding(newBinding, this, nullptr, bindingWrapper)); // notification is already handled in QPropertyBindingData::setBinding return static_cast &>(oldBinding); } bool setBinding(const QUntypedPropertyBinding &newBinding) { if (!newBinding.isNull() && newBinding.valueMetaType() != QMetaType::fromType()) return false; setBinding(static_cast &>(newBinding)); return true; } #ifndef Q_CLANG_QDOC template QPropertyBinding setBinding(Functor &&f, const QPropertyBindingSourceLocation &location = QT_PROPERTY_DEFAULT_BINDING_LOCATION, std::enable_if_t> * = nullptr) { return setBinding(Qt::makePropertyBinding(std::forward(f), location)); } #else template QPropertyBinding setBinding(Functor f); #endif bool hasBinding() const { auto *bd = qGetBindingStorage(owner())->bindingData(this); return bd && bd->binding() != nullptr; } void removeBindingUnlessInWrapper() { QBindingStorage *storage = qGetBindingStorage(owner()); auto *bd = storage->bindingData(this); // make sure we don't remove the binding if called from the bindingWrapper const bool inWrapper = inBindingWrapper(storage); if (bd && !inWrapper) bd->removeBinding(); } void notify() { QBindingStorage *storage = qGetBindingStorage(owner()); auto bd = storage->bindingData(this, false); const bool inWrapper = inBindingWrapper(storage); if (bd && !inWrapper) notify(bd); if constexpr (Signal != nullptr) { if constexpr (SignalTakesValue::value) (owner()->*Signal)(value()); else (owner()->*Signal)(); } } QPropertyBinding binding() const { auto *bd = qGetBindingStorage(owner())->bindingData(this); return static_cast &&>(QUntypedPropertyBinding(bd ? bd->binding() : nullptr)); } QPropertyBinding takeBinding() { return setBinding(QPropertyBinding()); } template QPropertyChangeHandler onValueChanged(Functor f) { static_assert(std::is_invocable_v, "Functor callback must be callable without any parameters"); return QPropertyChangeHandler(*this, f); } template QPropertyChangeHandler subscribe(Functor f) { static_assert(std::is_invocable_v, "Functor callback must be callable without any parameters"); f(); return onValueChanged(f); } template QPropertyNotifier addNotifier(Functor f) { static_assert(std::is_invocable_v, "Functor callback must be callable without any parameters"); return QPropertyNotifier(*this, f); } QtPrivate::QPropertyBindingData &bindingData() const { auto *storage = const_cast(qGetBindingStorage(owner())); return *storage->bindingData(const_cast(this), true); } private: void notify(const QtPrivate::QPropertyBindingData *binding) { if (binding) binding->notifyObservers(this, qGetBindingStorage(owner())); } }; namespace QtPrivate { template class QBindableInterfaceForProperty, std::void_t> { using Property = QObjectCompatProperty; using T = typename Property::value_type; public: static constexpr QBindableInterface iface = { [](const QUntypedPropertyData *d, void *value) -> void { *static_cast(value) = static_cast(d)->value(); }, [](QUntypedPropertyData *d, const void *value) -> void { (static_cast(d)->owner()->*Setter)(*static_cast(value)); }, [](const QUntypedPropertyData *d) -> QUntypedPropertyBinding { return static_cast(d)->binding(); }, [](QUntypedPropertyData *d, const QUntypedPropertyBinding &binding) -> QUntypedPropertyBinding { return static_cast(d)->setBinding(static_cast &>(binding)); }, [](const QUntypedPropertyData *d, const QPropertyBindingSourceLocation &location) -> QUntypedPropertyBinding { return Qt::makePropertyBinding([d]() -> T { return static_cast(d)->value(); }, location); }, [](const QUntypedPropertyData *d, QPropertyObserver *observer) -> void { observer->setSource(static_cast(d)->bindingData()); }, []() { return QMetaType::fromType(); } }; }; } #define QT_OBJECT_COMPAT_PROPERTY_4(Class, Type, name, setter) \ static constexpr size_t _qt_property_##name##_offset() { \ QT_WARNING_PUSH QT_WARNING_DISABLE_INVALID_OFFSETOF \ return offsetof(Class, name); \ QT_WARNING_POP \ } \ QObjectCompatProperty name; #define QT_OBJECT_COMPAT_PROPERTY_5(Class, Type, name, setter, signal) \ static constexpr size_t _qt_property_##name##_offset() { \ QT_WARNING_PUSH QT_WARNING_DISABLE_INVALID_OFFSETOF \ return offsetof(Class, name); \ QT_WARNING_POP \ } \ QObjectCompatProperty name; #define Q_OBJECT_COMPAT_PROPERTY(...) \ QT_WARNING_PUSH QT_WARNING_DISABLE_INVALID_OFFSETOF \ QT_OVERLOADED_MACRO(QT_OBJECT_COMPAT_PROPERTY, __VA_ARGS__) \ QT_WARNING_POP #define QT_OBJECT_COMPAT_PROPERTY_WITH_ARGS_5(Class, Type, name, setter, value) \ static constexpr size_t _qt_property_##name##_offset() { \ QT_WARNING_PUSH QT_WARNING_DISABLE_INVALID_OFFSETOF \ return offsetof(Class, name); \ QT_WARNING_POP \ } \ QObjectCompatProperty name = \ QObjectCompatProperty( \ value); #define QT_OBJECT_COMPAT_PROPERTY_WITH_ARGS_6(Class, Type, name, setter, signal, value) \ static constexpr size_t _qt_property_##name##_offset() { \ QT_WARNING_PUSH QT_WARNING_DISABLE_INVALID_OFFSETOF \ return offsetof(Class, name); \ QT_WARNING_POP \ } \ QObjectCompatProperty name = \ QObjectCompatProperty(value); #define Q_OBJECT_COMPAT_PROPERTY_WITH_ARGS(...) \ QT_WARNING_PUSH QT_WARNING_DISABLE_INVALID_OFFSETOF \ QT_OVERLOADED_MACRO(QT_OBJECT_COMPAT_PROPERTY_WITH_ARGS, __VA_ARGS__) \ QT_WARNING_POP namespace QtPrivate { Q_CORE_EXPORT BindingEvaluationState *suspendCurrentBindingStatus(); Q_CORE_EXPORT void restoreBindingStatus(BindingEvaluationState *status); } struct QUntypedBindablePrivate { static QtPrivate::QBindableInterface const *getInterface(const QUntypedBindable &bindable) { return bindable.iface; } static QUntypedPropertyData *getPropertyData(const QUntypedBindable &bindable) { return bindable.data; } }; inline void QPropertyBindingPrivate::evaluateRecursive_inline(QBindingStatus *status) { if (updating) { error = QPropertyBindingError(QPropertyBindingError::BindingLoop); if (isQQmlPropertyBinding) errorCallBack(this); return; } /* * Evaluating the binding might lead to the binding being broken. This can * cause ref to reach zero at the end of the function. However, the * updateGuard's destructor will then still trigger, trying to set the * updating bool to its old value * To prevent this, we create a QPropertyBindingPrivatePtr which ensures * that the object is still alive when updateGuard's dtor runs. */ QPropertyBindingPrivatePtr keepAlive {this}; QScopedValueRollback updateGuard(updating, true); QtPrivate::BindingEvaluationState evaluationFrame(this, status); auto bindingFunctor = reinterpret_cast(this) + QPropertyBindingPrivate::getSizeEnsuringAlignment(); bool changed = false; if (hasBindingWrapper) { changed = staticBindingWrapper(metaType, propertyDataPtr, {vtable, bindingFunctor}); } else { changed = vtable->call(metaType, propertyDataPtr, bindingFunctor); } // If there was a change, we must set pendingNotify. // If there was not, we must not clear it, as that only should happen in notifyRecursive pendingNotify = pendingNotify || changed; if (!changed || !firstObserver) return; firstObserver.noSelfDependencies(this); firstObserver.evaluateBindings(status); } QT_END_NAMESPACE #endif // QPROPERTY_P_H