qobject_impl.h
1、qobject_impl.h
/**************************************************************************** ** ** Copyright (C) 2016 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 Q_QDOC #ifndef QOBJECT_H #error Do not include qobject_impl.h directly #endif #if 0 #pragma qt_sync_skip_header_check #pragma qt_sync_stop_processing #endif QT_BEGIN_NAMESPACE namespace QtPrivate { /* Logic to statically generate the array of qMetaTypeId ConnectionTypes<FunctionPointer<Signal>::Arguments>::types() returns an array of int that is suitable for the types arguments of the connection functions. The array only exist of all the types are declared as a metatype (detected using the TypesAreDeclaredMetaType helper struct) If one of the type is not declared, the function return 0 and the signal cannot be used in queued connection. */ template <typename ArgList> struct TypesAreDeclaredMetaType { enum { Value = false }; }; template <> struct TypesAreDeclaredMetaType<List<>> { enum { Value = true }; }; template <typename Arg, typename... Tail> struct TypesAreDeclaredMetaType<List<Arg, Tail...> > { enum { Value = QMetaTypeId2<Arg>::Defined && TypesAreDeclaredMetaType<List<Tail...>>::Value }; }; template <typename ArgList, bool Declared = TypesAreDeclaredMetaType<ArgList>::Value > struct ConnectionTypes { static const int *types() { return nullptr; } }; template <> struct ConnectionTypes<List<>, true> { static const int *types() { return nullptr; } }; template <typename... Args> struct ConnectionTypes<List<Args...>, true> { static const int *types() { static const int t[sizeof...(Args) + 1] = { (QtPrivate::QMetaTypeIdHelper<Args>::qt_metatype_id())..., 0 }; return t; } }; // implementation of QSlotObjectBase for which the slot is a static function // Args and R are the List of arguments and the returntype of the signal to which the slot is connected. template<typename Func, typename Args, typename R> class QStaticSlotObject : public QSlotObjectBase { typedef QtPrivate::FunctionPointer<Func> FuncType; Func function; static void impl(int which, QSlotObjectBase *this_, QObject *r, void **a, bool *ret) { switch (which) { case Destroy: delete static_cast<QStaticSlotObject*>(this_); break; case Call: FuncType::template call<Args, R>(static_cast<QStaticSlotObject*>(this_)->function, r, a); break; case Compare: // not implemented case NumOperations: Q_UNUSED(ret); } } public: explicit QStaticSlotObject(Func f) : QSlotObjectBase(&impl), function(f) {} }; } QT_END_NAMESPACE #endif
2、qobject.h
/**************************************************************************** ** ** Copyright (C) 2016 The Qt Company Ltd. ** Copyright (C) 2013 Olivier Goffart <ogoffart@woboq.com> ** 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 QOBJECT_H #define QOBJECT_H #ifndef QT_NO_QOBJECT #include <QtCore/qobjectdefs.h> #include <QtCore/qstring.h> #include <QtCore/qbytearray.h> #include <QtCore/qlist.h> #ifdef QT_INCLUDE_COMPAT #include <QtCore/qcoreevent.h> #endif #include <QtCore/qscopedpointer.h> #include <QtCore/qmetatype.h> #include <QtCore/qobject_impl.h> #if QT_HAS_INCLUDE(<chrono>) # include <chrono> #endif QT_BEGIN_NAMESPACE class QEvent; class QTimerEvent; class QChildEvent; struct QMetaObject; class QVariant; class QObjectPrivate; class QObject; class QThread; class QWidget; #ifndef QT_NO_REGEXP class QRegExp; #endif #if QT_CONFIG(regularexpression) class QRegularExpression; #endif #ifndef QT_NO_USERDATA class QObjectUserData; #endif struct QDynamicMetaObjectData; typedef QList<QObject*> QObjectList; Q_CORE_EXPORT void qt_qFindChildren_helper(const QObject *parent, const QString &name, const QMetaObject &mo, QList<void *> *list, Qt::FindChildOptions options); Q_CORE_EXPORT void qt_qFindChildren_helper(const QObject *parent, const QRegExp &re, const QMetaObject &mo, QList<void *> *list, Qt::FindChildOptions options); Q_CORE_EXPORT void qt_qFindChildren_helper(const QObject *parent, const QRegularExpression &re, const QMetaObject &mo, QList<void *> *list, Qt::FindChildOptions options); Q_CORE_EXPORT QObject *qt_qFindChild_helper(const QObject *parent, const QString &name, const QMetaObject &mo, Qt::FindChildOptions options); class Q_CORE_EXPORT QObjectData { public: virtual ~QObjectData() = 0; QObject *q_ptr; QObject *parent; QObjectList children; uint isWidget : 1; uint blockSig : 1; uint wasDeleted : 1; uint isDeletingChildren : 1; uint sendChildEvents : 1; uint receiveChildEvents : 1; uint isWindow : 1; //for QWindow uint deleteLaterCalled : 1; uint unused : 24; int postedEvents; QDynamicMetaObjectData *metaObject; QMetaObject *dynamicMetaObject() const; }; class Q_CORE_EXPORT QObject { Q_OBJECT Q_PROPERTY(QString objectName READ objectName WRITE setObjectName NOTIFY objectNameChanged) Q_DECLARE_PRIVATE(QObject) public: Q_INVOKABLE explicit QObject(QObject *parent=nullptr); virtual ~QObject(); virtual bool event(QEvent *event); virtual bool eventFilter(QObject *watched, QEvent *event); #if defined(QT_NO_TRANSLATION) static QString tr(const char *sourceText, const char * = nullptr, int = -1) { return QString::fromUtf8(sourceText); } #if QT_DEPRECATED_SINCE(5, 0) QT_DEPRECATED static QString trUtf8(const char *sourceText, const char * = nullptr, int = -1) { return QString::fromUtf8(sourceText); } #endif #endif //QT_NO_TRANSLATION QString objectName() const; void setObjectName(const QString &name); inline bool isWidgetType() const { return d_ptr->isWidget; } inline bool isWindowType() const { return d_ptr->isWindow; } inline bool signalsBlocked() const Q_DECL_NOTHROW { return d_ptr->blockSig; } bool blockSignals(bool b) Q_DECL_NOTHROW; QThread *thread() const; void moveToThread(QThread *thread); int startTimer(int interval, Qt::TimerType timerType = Qt::CoarseTimer); #if QT_HAS_INCLUDE(<chrono>) Q_ALWAYS_INLINE int startTimer(std::chrono::milliseconds time, Qt::TimerType timerType = Qt::CoarseTimer) { return startTimer(int(time.count()), timerType); } #endif void killTimer(int id); template<typename T> inline T findChild(const QString &aName = QString(), Qt::FindChildOptions options = Qt::FindChildrenRecursively) const { typedef typename std::remove_cv<typename std::remove_pointer<T>::type>::type ObjType; return static_cast<T>(qt_qFindChild_helper(this, aName, ObjType::staticMetaObject, options)); } template<typename T> inline QList<T> findChildren(const QString &aName = QString(), Qt::FindChildOptions options = Qt::FindChildrenRecursively) const { typedef typename std::remove_cv<typename std::remove_pointer<T>::type>::type ObjType; QList<T> list; qt_qFindChildren_helper(this, aName, ObjType::staticMetaObject, reinterpret_cast<QList<void *> *>(&list), options); return list; } #ifndef QT_NO_REGEXP template<typename T> inline QList<T> findChildren(const QRegExp &re, Qt::FindChildOptions options = Qt::FindChildrenRecursively) const { typedef typename std::remove_cv<typename std::remove_pointer<T>::type>::type ObjType; QList<T> list; qt_qFindChildren_helper(this, re, ObjType::staticMetaObject, reinterpret_cast<QList<void *> *>(&list), options); return list; } #endif #if QT_CONFIG(regularexpression) template<typename T> inline QList<T> findChildren(const QRegularExpression &re, Qt::FindChildOptions options = Qt::FindChildrenRecursively) const { typedef typename std::remove_cv<typename std::remove_pointer<T>::type>::type ObjType; QList<T> list; qt_qFindChildren_helper(this, re, ObjType::staticMetaObject, reinterpret_cast<QList<void *> *>(&list), options); return list; } #endif // QT_CONFIG(regularexpression) inline const QObjectList &children() const { return d_ptr->children; } void setParent(QObject *parent); void installEventFilter(QObject *filterObj); void removeEventFilter(QObject *obj); static QMetaObject::Connection connect(const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType = Qt::AutoConnection); static QMetaObject::Connection connect(const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type = Qt::AutoConnection); inline QMetaObject::Connection connect(const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type = Qt::AutoConnection) const; #ifdef Q_CLANG_QDOC template<typename PointerToMemberFunction> static QMetaObject::Connection connect(const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method, Qt::ConnectionType type = Qt::AutoConnection); template<typename PointerToMemberFunction, typename Functor> static QMetaObject::Connection connect(const QObject *sender, PointerToMemberFunction signal, Functor functor); template<typename PointerToMemberFunction, typename Functor> static QMetaObject::Connection connect(const QObject *sender, PointerToMemberFunction signal, const QObject *context, Functor functor, Qt::ConnectionType type = Qt::AutoConnection); #else //Connect a signal to a pointer to qobject member function template <typename Func1, typename Func2> static inline QMetaObject::Connection connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, const typename QtPrivate::FunctionPointer<Func2>::Object *receiver, Func2 slot, Qt::ConnectionType type = Qt::AutoConnection) { typedef QtPrivate::FunctionPointer<Func1> SignalType; typedef QtPrivate::FunctionPointer<Func2> SlotType; Q_STATIC_ASSERT_X(QtPrivate::HasQ_OBJECT_Macro<typename SignalType::Object>::Value, "No Q_OBJECT in the class with the signal"); //compilation error if the arguments does not match. Q_STATIC_ASSERT_X(int(SignalType::ArgumentCount) >= int(SlotType::ArgumentCount), "The slot requires more arguments than the signal provides."); Q_STATIC_ASSERT_X((QtPrivate::CheckCompatibleArguments<typename SignalType::Arguments, typename SlotType::Arguments>::value), "Signal and slot arguments are not compatible."); Q_STATIC_ASSERT_X((QtPrivate::AreArgumentsCompatible<typename SlotType::ReturnType, typename SignalType::ReturnType>::value), "Return type of the slot is not compatible with the return type of the signal."); const int *types = nullptr; if (type == Qt::QueuedConnection || type == Qt::BlockingQueuedConnection) types = QtPrivate::ConnectionTypes<typename SignalType::Arguments>::types(); return connectImpl(sender, reinterpret_cast<void **>(&signal), receiver, reinterpret_cast<void **>(&slot), new QtPrivate::QSlotObject<Func2, typename QtPrivate::List_Left<typename SignalType::Arguments, SlotType::ArgumentCount>::Value, typename SignalType::ReturnType>(slot), type, types, &SignalType::Object::staticMetaObject); } //connect to a function pointer (not a member) template <typename Func1, typename Func2> static inline typename std::enable_if<int(QtPrivate::FunctionPointer<Func2>::ArgumentCount) >= 0, QMetaObject::Connection>::type connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, Func2 slot) { return connect(sender, signal, sender, slot, Qt::DirectConnection); } //connect to a function pointer (not a member) template <typename Func1, typename Func2> static inline typename std::enable_if<int(QtPrivate::FunctionPointer<Func2>::ArgumentCount) >= 0 && !QtPrivate::FunctionPointer<Func2>::IsPointerToMemberFunction, QMetaObject::Connection>::type connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, const QObject *context, Func2 slot, Qt::ConnectionType type = Qt::AutoConnection) { typedef QtPrivate::FunctionPointer<Func1> SignalType; typedef QtPrivate::FunctionPointer<Func2> SlotType; Q_STATIC_ASSERT_X(QtPrivate::HasQ_OBJECT_Macro<typename SignalType::Object>::Value, "No Q_OBJECT in the class with the signal"); //compilation error if the arguments does not match. Q_STATIC_ASSERT_X(int(SignalType::ArgumentCount) >= int(SlotType::ArgumentCount), "The slot requires more arguments than the signal provides."); Q_STATIC_ASSERT_X((QtPrivate::CheckCompatibleArguments<typename SignalType::Arguments, typename SlotType::Arguments>::value), "Signal and slot arguments are not compatible."); Q_STATIC_ASSERT_X((QtPrivate::AreArgumentsCompatible<typename SlotType::ReturnType, typename SignalType::ReturnType>::value), "Return type of the slot is not compatible with the return type of the signal."); const int *types = nullptr; if (type == Qt::QueuedConnection || type == Qt::BlockingQueuedConnection) types = QtPrivate::ConnectionTypes<typename SignalType::Arguments>::types(); return connectImpl(sender, reinterpret_cast<void **>(&signal), context, nullptr, new QtPrivate::QStaticSlotObject<Func2, typename QtPrivate::List_Left<typename SignalType::Arguments, SlotType::ArgumentCount>::Value, typename SignalType::ReturnType>(slot), type, types, &SignalType::Object::staticMetaObject); } //connect to a functor template <typename Func1, typename Func2> static inline typename std::enable_if<QtPrivate::FunctionPointer<Func2>::ArgumentCount == -1, QMetaObject::Connection>::type connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, Func2 slot) { return connect(sender, signal, sender, std::move(slot), Qt::DirectConnection); } //connect to a functor, with a "context" object defining in which event loop is going to be executed template <typename Func1, typename Func2> static inline typename std::enable_if<QtPrivate::FunctionPointer<Func2>::ArgumentCount == -1, QMetaObject::Connection>::type connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, const QObject *context, Func2 slot, Qt::ConnectionType type = Qt::AutoConnection) { typedef QtPrivate::FunctionPointer<Func1> SignalType; const int FunctorArgumentCount = QtPrivate::ComputeFunctorArgumentCount<Func2 , typename SignalType::Arguments>::Value; Q_STATIC_ASSERT_X((FunctorArgumentCount >= 0), "Signal and slot arguments are not compatible."); const int SlotArgumentCount = (FunctorArgumentCount >= 0) ? FunctorArgumentCount : 0; typedef typename QtPrivate::FunctorReturnType<Func2, typename QtPrivate::List_Left<typename SignalType::Arguments, SlotArgumentCount>::Value>::Value SlotReturnType; Q_STATIC_ASSERT_X((QtPrivate::AreArgumentsCompatible<SlotReturnType, typename SignalType::ReturnType>::value), "Return type of the slot is not compatible with the return type of the signal."); Q_STATIC_ASSERT_X(QtPrivate::HasQ_OBJECT_Macro<typename SignalType::Object>::Value, "No Q_OBJECT in the class with the signal"); const int *types = nullptr; if (type == Qt::QueuedConnection || type == Qt::BlockingQueuedConnection) types = QtPrivate::ConnectionTypes<typename SignalType::Arguments>::types(); return connectImpl(sender, reinterpret_cast<void **>(&signal), context, nullptr, new QtPrivate::QFunctorSlotObject<Func2, SlotArgumentCount, typename QtPrivate::List_Left<typename SignalType::Arguments, SlotArgumentCount>::Value, typename SignalType::ReturnType>(std::move(slot)), type, types, &SignalType::Object::staticMetaObject); } #endif //Q_CLANG_QDOC static bool disconnect(const QObject *sender, const char *signal, const QObject *receiver, const char *member); static bool disconnect(const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member); inline bool disconnect(const char *signal = nullptr, const QObject *receiver = nullptr, const char *member = nullptr) const { return disconnect(this, signal, receiver, member); } inline bool disconnect(const QObject *receiver, const char *member = nullptr) const { return disconnect(this, nullptr, receiver, member); } static bool disconnect(const QMetaObject::Connection &); #ifdef Q_CLANG_QDOC template<typename PointerToMemberFunction> static bool disconnect(const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method); #else template <typename Func1, typename Func2> static inline bool disconnect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, const typename QtPrivate::FunctionPointer<Func2>::Object *receiver, Func2 slot) { typedef QtPrivate::FunctionPointer<Func1> SignalType; typedef QtPrivate::FunctionPointer<Func2> SlotType; Q_STATIC_ASSERT_X(QtPrivate::HasQ_OBJECT_Macro<typename SignalType::Object>::Value, "No Q_OBJECT in the class with the signal"); //compilation error if the arguments does not match. Q_STATIC_ASSERT_X((QtPrivate::CheckCompatibleArguments<typename SignalType::Arguments, typename SlotType::Arguments>::value), "Signal and slot arguments are not compatible."); return disconnectImpl(sender, reinterpret_cast<void **>(&signal), receiver, reinterpret_cast<void **>(&slot), &SignalType::Object::staticMetaObject); } template <typename Func1> static inline bool disconnect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, const QObject *receiver, void **zero) { // This is the overload for when one wish to disconnect a signal from any slot. (slot=nullptr) // Since the function template parameter cannot be deduced from '0', we use a // dummy void ** parameter that must be equal to 0 Q_ASSERT(!zero); typedef QtPrivate::FunctionPointer<Func1> SignalType; return disconnectImpl(sender, reinterpret_cast<void **>(&signal), receiver, zero, &SignalType::Object::staticMetaObject); } #endif //Q_CLANG_QDOC #if QT_VERSION < QT_VERSION_CHECK(6, 0, 0) void dumpObjectTree(); // ### Qt 6: remove void dumpObjectInfo(); // ### Qt 6: remove #endif void dumpObjectTree() const; void dumpObjectInfo() const; #ifndef QT_NO_PROPERTIES bool setProperty(const char *name, const QVariant &value); QVariant property(const char *name) const; QList<QByteArray> dynamicPropertyNames() const; #endif // QT_NO_PROPERTIES #ifndef QT_NO_USERDATA static uint registerUserData(); void setUserData(uint id, QObjectUserData* data); QObjectUserData* userData(uint id) const; #endif // QT_NO_USERDATA Q_SIGNALS: void destroyed(QObject * = nullptr); void objectNameChanged(const QString &objectName, QPrivateSignal); public: inline QObject *parent() const { return d_ptr->parent; } inline bool inherits(const char *classname) const { return const_cast<QObject *>(this)->qt_metacast(classname) != nullptr; } public Q_SLOTS: void deleteLater(); protected: QObject *sender() const; int senderSignalIndex() const; int receivers(const char* signal) const; bool isSignalConnected(const QMetaMethod &signal) const; virtual void timerEvent(QTimerEvent *event); virtual void childEvent(QChildEvent *event); virtual void customEvent(QEvent *event); virtual void connectNotify(const QMetaMethod &signal); virtual void disconnectNotify(const QMetaMethod &signal); protected: QObject(QObjectPrivate &dd, QObject *parent = nullptr); protected: QScopedPointer<QObjectData> d_ptr; static const QMetaObject staticQtMetaObject; friend inline const QMetaObject *qt_getQtMetaObject() Q_DECL_NOEXCEPT; friend struct QMetaObject; friend struct QMetaObjectPrivate; friend class QMetaCallEvent; friend class QApplication; friend class QApplicationPrivate; friend class QCoreApplication; friend class QCoreApplicationPrivate; friend class QWidget; friend class QThreadData; private: Q_DISABLE_COPY(QObject) Q_PRIVATE_SLOT(d_func(), void _q_reregisterTimers(void *)) private: static QMetaObject::Connection connectImpl(const QObject *sender, void **signal, const QObject *receiver, void **slotPtr, QtPrivate::QSlotObjectBase *slot, Qt::ConnectionType type, const int *types, const QMetaObject *senderMetaObject); static bool disconnectImpl(const QObject *sender, void **signal, const QObject *receiver, void **slot, const QMetaObject *senderMetaObject); }; inline QMetaObject::Connection QObject::connect(const QObject *asender, const char *asignal, const char *amember, Qt::ConnectionType atype) const { return connect(asender, asignal, this, amember, atype); } inline const QMetaObject *qt_getQtMetaObject() Q_DECL_NOEXCEPT { return &QObject::staticQtMetaObject; } #ifndef QT_NO_USERDATA class Q_CORE_EXPORT QObjectUserData { public: virtual ~QObjectUserData(); }; #endif #if QT_DEPRECATED_SINCE(5, 0) template<typename T> inline QT_DEPRECATED T qFindChild(const QObject *o, const QString &name = QString()) { return o->findChild<T>(name); } template<typename T> inline QT_DEPRECATED QList<T> qFindChildren(const QObject *o, const QString &name = QString()) { return o->findChildren<T>(name); } #if !defined(QT_NO_REGEXP) || defined(Q_CLANG_QDOC) template<typename T> inline QT_DEPRECATED QList<T> qFindChildren(const QObject *o, const QRegExp &re) { return o->findChildren<T>(re); } #endif #endif //QT_DEPRECATED template <class T> inline T qobject_cast(QObject *object) { typedef typename std::remove_cv<typename std::remove_pointer<T>::type>::type ObjType; Q_STATIC_ASSERT_X(QtPrivate::HasQ_OBJECT_Macro<ObjType>::Value, "qobject_cast requires the type to have a Q_OBJECT macro"); return static_cast<T>(ObjType::staticMetaObject.cast(object)); } template <class T> inline T qobject_cast(const QObject *object) { typedef typename std::remove_cv<typename std::remove_pointer<T>::type>::type ObjType; Q_STATIC_ASSERT_X(QtPrivate::HasQ_OBJECT_Macro<ObjType>::Value, "qobject_cast requires the type to have a Q_OBJECT macro"); return static_cast<T>(ObjType::staticMetaObject.cast(object)); } template <class T> inline const char * qobject_interface_iid() { return nullptr; } #if !defined(Q_MOC_RUN) && !defined(Q_CLANG_QDOC) # define Q_DECLARE_INTERFACE(IFace, IId) \ template <> inline const char *qobject_interface_iid<IFace *>() \ { return IId; } \ template <> inline IFace *qobject_cast<IFace *>(QObject *object) \ { return reinterpret_cast<IFace *>((object ? object->qt_metacast(IId) : nullptr)); } \ template <> inline IFace *qobject_cast<IFace *>(const QObject *object) \ { return reinterpret_cast<IFace *>((object ? const_cast<QObject *>(object)->qt_metacast(IId) : nullptr)); } #endif // Q_MOC_RUN #ifndef QT_NO_DEBUG_STREAM Q_CORE_EXPORT QDebug operator<<(QDebug, const QObject *); #endif class QSignalBlocker { public: inline explicit QSignalBlocker(QObject *o) Q_DECL_NOTHROW; inline explicit QSignalBlocker(QObject &o) Q_DECL_NOTHROW; inline ~QSignalBlocker(); #ifdef Q_COMPILER_RVALUE_REFS inline QSignalBlocker(QSignalBlocker &&other) Q_DECL_NOTHROW; inline QSignalBlocker &operator=(QSignalBlocker &&other) Q_DECL_NOTHROW; #endif inline void reblock() Q_DECL_NOTHROW; inline void unblock() Q_DECL_NOTHROW; private: Q_DISABLE_COPY(QSignalBlocker) QObject * m_o; bool m_blocked; bool m_inhibited; }; QSignalBlocker::QSignalBlocker(QObject *o) Q_DECL_NOTHROW : m_o(o), m_blocked(o && o->blockSignals(true)), m_inhibited(false) {} QSignalBlocker::QSignalBlocker(QObject &o) Q_DECL_NOTHROW : m_o(&o), m_blocked(o.blockSignals(true)), m_inhibited(false) {} #ifdef Q_COMPILER_RVALUE_REFS QSignalBlocker::QSignalBlocker(QSignalBlocker &&other) Q_DECL_NOTHROW : m_o(other.m_o), m_blocked(other.m_blocked), m_inhibited(other.m_inhibited) { other.m_o = nullptr; } QSignalBlocker &QSignalBlocker::operator=(QSignalBlocker &&other) Q_DECL_NOTHROW { if (this != &other) { // if both *this and other block the same object's signals: // unblock *this iff our dtor would unblock, but other's wouldn't if (m_o != other.m_o || (!m_inhibited && other.m_inhibited)) unblock(); m_o = other.m_o; m_blocked = other.m_blocked; m_inhibited = other.m_inhibited; // disable other: other.m_o = nullptr; } return *this; } #endif QSignalBlocker::~QSignalBlocker() { if (m_o && !m_inhibited) m_o->blockSignals(m_blocked); } void QSignalBlocker::reblock() Q_DECL_NOTHROW { if (m_o) m_o->blockSignals(true); m_inhibited = false; } void QSignalBlocker::unblock() Q_DECL_NOTHROW { if (m_o) m_o->blockSignals(m_blocked); m_inhibited = true; } namespace QtPrivate { inline QObject & deref_for_methodcall(QObject &o) { return o; } inline QObject & deref_for_methodcall(QObject *o) { return *o; } } #define Q_SET_OBJECT_NAME(obj) QT_PREPEND_NAMESPACE(QtPrivate)::deref_for_methodcall(obj).setObjectName(QLatin1String(#obj)) QT_END_NAMESPACE #endif #endif // QOBJECT_H
3、qobject.cpp
/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Copyright (C) 2016 Intel Corporation.
** Copyright (C) 2013 Olivier Goffart <ogoffart@woboq.com>
** 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.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qobject.h"
#include "qobject_p.h"
#include "qmetaobject_p.h"
#include "qabstracteventdispatcher.h"
#include "qabstracteventdispatcher_p.h"
#include "qcoreapplication.h"
#include "qcoreapplication_p.h"
#include "qvariant.h"
#include "qmetaobject.h"
#include <qregexp.h>
#if QT_CONFIG(regularexpression)
# include <qregularexpression.h>
#endif
#include <qthread.h>
#include <private/qthread_p.h>
#include <qdebug.h>
#include <qpair.h>
#include <qvarlengtharray.h>
#include <qset.h>
#if QT_CONFIG(thread)
#include <qsemaphore.h>
#endif
#include <qsharedpointer.h>
#include <private/qorderedmutexlocker_p.h>
#include <private/qhooks_p.h>
#include <qtcore_tracepoints_p.h>
#include <new>
#include <ctype.h>
#include <limits.h>
QT_BEGIN_NAMESPACE
static int DIRECT_CONNECTION_ONLY = 0;
QDynamicMetaObjectData::~QDynamicMetaObjectData()
{
}
QAbstractDynamicMetaObject::~QAbstractDynamicMetaObject()
{
}
struct QSlotObjectBaseDeleter { // for use with QScopedPointer<QSlotObjectBase,...>
static void cleanup(QtPrivate::QSlotObjectBase *slot) {
if (slot) slot->destroyIfLastRef();
}
};
static int *queuedConnectionTypes(const QList<QByteArray> &typeNames)
{
int *types = new int [typeNames.count() + 1];
Q_CHECK_PTR(types);
for (int i = 0; i < typeNames.count(); ++i) {
const QByteArray typeName = typeNames.at(i);
if (typeName.endsWith('*'))
types[i] = QMetaType::VoidStar;
else
types[i] = QMetaType::type(typeName);
if (!types[i]) {
qWarning("QObject::connect: Cannot queue arguments of type '%s'\n"
"(Make sure '%s' is registered using qRegisterMetaType().)",
typeName.constData(), typeName.constData());
delete [] types;
return 0;
}
}
types[typeNames.count()] = 0;
return types;
}
static int *queuedConnectionTypes(const QArgumentType *argumentTypes, int argc)
{
QScopedArrayPointer<int> types(new int [argc + 1]);
for (int i = 0; i < argc; ++i) {
const QArgumentType &type = argumentTypes[i];
if (type.type())
types[i] = type.type();
else if (type.name().endsWith('*'))
types[i] = QMetaType::VoidStar;
else
types[i] = QMetaType::type(type.name());
if (!types[i]) {
qWarning("QObject::connect: Cannot queue arguments of type '%s'\n"
"(Make sure '%s' is registered using qRegisterMetaType().)",
type.name().constData(), type.name().constData());
return 0;
}
}
types[argc] = 0;
return types.take();
}
static QBasicMutex _q_ObjectMutexPool[131];
/**
* \internal
* mutex to be locked when accessing the connectionlists or the senders list
*/
static inline QMutex *signalSlotLock(const QObject *o)
{
return static_cast<QMutex *>(&_q_ObjectMutexPool[
uint(quintptr(o)) % sizeof(_q_ObjectMutexPool)/sizeof(QBasicMutex)]);
}
#if QT_VERSION < 0x60000
extern "C" Q_CORE_EXPORT void qt_addObject(QObject *)
{}
extern "C" Q_CORE_EXPORT void qt_removeObject(QObject *)
{}
#endif
struct QConnectionSenderSwitcher {
QObject *receiver;
QObjectPrivate::Sender *previousSender;
QObjectPrivate::Sender currentSender;
bool switched;
inline QConnectionSenderSwitcher() : switched(false) {}
inline QConnectionSenderSwitcher(QObject *receiver, QObject *sender, int signal_absolute_id)
{
switchSender(receiver, sender, signal_absolute_id);
}
inline void switchSender(QObject *receiver, QObject *sender, int signal_absolute_id)
{
this->receiver = receiver;
currentSender.sender = sender;
currentSender.signal = signal_absolute_id;
currentSender.ref = 1;
previousSender = QObjectPrivate::setCurrentSender(receiver, ¤tSender);
switched = true;
}
inline ~QConnectionSenderSwitcher()
{
if (switched)
QObjectPrivate::resetCurrentSender(receiver, ¤tSender, previousSender);
}
private:
Q_DISABLE_COPY(QConnectionSenderSwitcher)
};
void (*QAbstractDeclarativeData::destroyed)(QAbstractDeclarativeData *, QObject *) = 0;
void (*QAbstractDeclarativeData::destroyed_qml1)(QAbstractDeclarativeData *, QObject *) = 0;
void (*QAbstractDeclarativeData::parentChanged)(QAbstractDeclarativeData *, QObject *, QObject *) = 0;
void (*QAbstractDeclarativeData::signalEmitted)(QAbstractDeclarativeData *, QObject *, int, void **) = 0;
int (*QAbstractDeclarativeData::receivers)(QAbstractDeclarativeData *, const QObject *, int) = 0;
bool (*QAbstractDeclarativeData::isSignalConnected)(QAbstractDeclarativeData *, const QObject *, int) = 0;
void (*QAbstractDeclarativeData::setWidgetParent)(QObject *, QObject *) = 0;
QObjectData::~QObjectData() {}
QMetaObject *QObjectData::dynamicMetaObject() const
{
return metaObject->toDynamicMetaObject(q_ptr);
}
QObjectPrivate::QObjectPrivate(int version)
: threadData(0), connectionLists(0), senders(0), currentSender(0), currentChildBeingDeleted(0)
{
#ifdef QT_BUILD_INTERNAL
// Don't check the version parameter in internal builds.
// This allows incompatible versions to be loaded, possibly for testing.
Q_UNUSED(version);
#else
if (Q_UNLIKELY(version != QObjectPrivateVersion))
qFatal("Cannot mix incompatible Qt library (version 0x%x) with this library (version 0x%x)",
version, QObjectPrivateVersion);
#endif
// QObjectData initialization
q_ptr = 0;
parent = 0; // no parent yet. It is set by setParent()
isWidget = false; // assume not a widget object
blockSig = false; // not blocking signals
wasDeleted = false; // double-delete catcher
isDeletingChildren = false; // set by deleteChildren()
sendChildEvents = true; // if we should send ChildAdded and ChildRemoved events to parent
receiveChildEvents = true;
postedEvents = 0;
extraData = 0;
// connectedSignals[0] = connectedSignals[1] = 0; // already 0.
metaObject = 0;
isWindow = false;
deleteLaterCalled = false;
}
QObjectPrivate::~QObjectPrivate()
{
if (extraData && !extraData->runningTimers.isEmpty()) {
if (Q_LIKELY(threadData->thread == QThread::currentThread())) {
// unregister pending timers
if (threadData->hasEventDispatcher())
threadData->eventDispatcher.load()->unregisterTimers(q_ptr);
// release the timer ids back to the pool
for (int i = 0; i < extraData->runningTimers.size(); ++i)
QAbstractEventDispatcherPrivate::releaseTimerId(extraData->runningTimers.at(i));
} else {
qWarning("QObject::~QObject: Timers cannot be stopped from another thread");
}
}
if (postedEvents)
QCoreApplication::removePostedEvents(q_ptr, 0);
threadData->deref();
if (metaObject) metaObject->objectDestroyed(q_ptr);
#ifndef QT_NO_USERDATA
if (extraData)
qDeleteAll(extraData->userData);
#endif
delete extraData;
}
/*!
\internal
For a given metaobject, compute the signal offset, and the method offset (including signals)
*/
static void computeOffsets(const QMetaObject *metaobject, int *signalOffset, int *methodOffset)
{
*signalOffset = *methodOffset = 0;
const QMetaObject *m = metaobject->d.superdata;
while (m) {
const QMetaObjectPrivate *d = QMetaObjectPrivate::get(m);
*methodOffset += d->methodCount;
Q_ASSERT(d->revision >= 4);
*signalOffset += d->signalCount;
m = m->d.superdata;
}
}
/*
This vector contains the all connections from an object.
Each object may have one vector containing the lists of
connections for a given signal. The index in the vector correspond
to the signal index. The signal index is the one returned by
QObjectPrivate::signalIndex (not QMetaObject::indexOfSignal).
Negative index means connections to all signals.
This vector is protected by the object mutex (signalSlotMutexes())
Each Connection is also part of a 'senders' linked list. The mutex
of the receiver must be locked when touching the pointers of this
linked list.
*/
class QObjectConnectionListVector : public QVector<QObjectPrivate::ConnectionList>
{
public:
bool orphaned; //the QObject owner of this vector has been destroyed while the vector was inUse
bool dirty; //some Connection have been disconnected (their receiver is 0) but not removed from the list yet
int inUse; //number of functions that are currently accessing this object or its connections
QObjectPrivate::ConnectionList allsignals;
QObjectConnectionListVector()
: QVector<QObjectPrivate::ConnectionList>(), orphaned(false), dirty(false), inUse(0)
{ }
QObjectPrivate::ConnectionList &operator[](int at)
{
if (at < 0)
return allsignals;
return QVector<QObjectPrivate::ConnectionList>::operator[](at);
}
};
// Used by QAccessibleWidget
bool QObjectPrivate::isSender(const QObject *receiver, const char *signal) const
{
Q_Q(const QObject);
int signal_index = signalIndex(signal);
if (signal_index < 0)
return false;
QMutexLocker locker(signalSlotLock(q));
if (connectionLists) {
if (signal_index < connectionLists->count()) {
const QObjectPrivate::Connection *c =
connectionLists->at(signal_index).first;
while (c) {
if (c->receiver == receiver)
return true;
c = c->nextConnectionList;
}
}
}
return false;
}
// Used by QAccessibleWidget
QObjectList QObjectPrivate::receiverList(const char *signal) const
{
Q_Q(const QObject);
QObjectList returnValue;
int signal_index = signalIndex(signal);
if (signal_index < 0)
return returnValue;
QMutexLocker locker(signalSlotLock(q));
if (connectionLists) {
if (signal_index < connectionLists->count()) {
const QObjectPrivate::Connection *c = connectionLists->at(signal_index).first;
while (c) {
if (c->receiver)
returnValue << c->receiver;
c = c->nextConnectionList;
}
}
}
return returnValue;
}
// Used by QAccessibleWidget
QObjectList QObjectPrivate::senderList() const
{
QObjectList returnValue;
QMutexLocker locker(signalSlotLock(q_func()));
for (Connection *c = senders; c; c = c->next)
returnValue << c->sender;
return returnValue;
}
/*!
\internal
Add the connection \a c to the list of connections of the sender's object
for the specified \a signal
The signalSlotLock() of the sender and receiver must be locked while calling
this function
Will also add the connection in the sender's list of the receiver.
*/
void QObjectPrivate::addConnection(int signal, Connection *c)
{
Q_ASSERT(c->sender == q_ptr);
if (!connectionLists)
connectionLists = new QObjectConnectionListVector();
if (signal >= connectionLists->count())
connectionLists->resize(signal + 1);
ConnectionList &connectionList = (*connectionLists)[signal];
if (connectionList.last) {
connectionList.last->nextConnectionList = c;
} else {
connectionList.first = c;
}
connectionList.last = c;
cleanConnectionLists();
c->prev = &(QObjectPrivate::get(c->receiver)->senders);
c->next = *c->prev;
*c->prev = c;
if (c->next)
c->next->prev = &c->next;
if (signal < 0) {
connectedSignals[0].store(~0);
connectedSignals[1].store(~0);
} else if (signal < (int)sizeof(connectedSignals) * 8) {
connectedSignals[signal >> 5].store(connectedSignals[signal >> 5].load() | (1 << (signal & 0x1f)));
}
}
void QObjectPrivate::cleanConnectionLists()
{
if (connectionLists->dirty && !connectionLists->inUse) {
// remove broken connections
bool allConnected = false;
for (int signal = -1; signal < connectionLists->count(); ++signal) {
QObjectPrivate::ConnectionList &connectionList =
(*connectionLists)[signal];
// Set to the last entry in the connection list that was *not*
// deleted. This is needed to update the list's last pointer
// at the end of the cleanup.
QObjectPrivate::Connection *last = 0;
QObjectPrivate::Connection **prev = &connectionList.first;
QObjectPrivate::Connection *c = *prev;
bool connected = false; // whether the signal is still connected somewhere
while (c) {
if (c->receiver) {
last = c;
prev = &c->nextConnectionList;
c = *prev;
connected = true;
} else {
QObjectPrivate::Connection *next = c->nextConnectionList;
*prev = next;
c->deref();
c = next;
}
}
// Correct the connection list's last pointer.
// As conectionList.last could equal last, this could be a noop
connectionList.last = last;
if (!allConnected && !connected && signal >= 0
&& size_t(signal) < sizeof(connectedSignals) * 8) {
// This signal is no longer connected
connectedSignals[signal >> 5].store(connectedSignals[signal >> 5].load() & ~(1 << (signal & 0x1f)));
} else if (signal == -1) {
allConnected = connected;
}
}
connectionLists->dirty = false;
}
}
/*!
\internal
*/
QMetaCallEvent::QMetaCallEvent(ushort method_offset, ushort method_relative, QObjectPrivate::StaticMetaCallFunction callFunction,
const QObject *sender, int signalId,
int nargs, int *types, void **args, QSemaphore *semaphore)
: QEvent(MetaCall), slotObj_(0), sender_(sender), signalId_(signalId),
nargs_(nargs), types_(types), args_(args), semaphore_(semaphore),
callFunction_(callFunction), method_offset_(method_offset), method_relative_(method_relative)
{ }
/*!
\internal
*/
QMetaCallEvent::QMetaCallEvent(QtPrivate::QSlotObjectBase *slotO, const QObject *sender, int signalId,
int nargs, int *types, void **args, QSemaphore *semaphore)
: QEvent(MetaCall), slotObj_(slotO), sender_(sender), signalId_(signalId),
nargs_(nargs), types_(types), args_(args), semaphore_(semaphore),
callFunction_(0), method_offset_(0), method_relative_(ushort(-1))
{
if (slotObj_)
slotObj_->ref();
}
/*!
\internal
*/
QMetaCallEvent::~QMetaCallEvent()
{
if (types_) {
for (int i = 0; i < nargs_; ++i) {
if (types_[i] && args_[i])
QMetaType::destroy(types_[i], args_[i]);
}
free(types_);
free(args_);
}
#if QT_CONFIG(thread)
if (semaphore_)
semaphore_->release();
#endif
if (slotObj_)
slotObj_->destroyIfLastRef();
}
/*!
\internal
*/
void QMetaCallEvent::placeMetaCall(QObject *object)
{
if (slotObj_) {
slotObj_->call(object, args_);
} else if (callFunction_ && method_offset_ <= object->metaObject()->methodOffset()) {
callFunction_(object, QMetaObject::InvokeMetaMethod, method_relative_, args_);
} else {
QMetaObject::metacall(object, QMetaObject::InvokeMetaMethod, method_offset_ + method_relative_, args_);
}
}
/*!
\class QSignalBlocker
\brief Exception-safe wrapper around QObject::blockSignals().
\since 5.3
\ingroup objectmodel
\inmodule QtCore
\reentrant
QSignalBlocker can be used wherever you would otherwise use a
pair of calls to blockSignals(). It blocks signals in its
constructor and in the destructor it resets the state to what
it was before the constructor ran.
\snippet code/src_corelib_kernel_qobject.cpp 53
is thus equivalent to
\snippet code/src_corelib_kernel_qobject.cpp 54
except the code using QSignalBlocker is safe in the face of
exceptions.
\sa QMutexLocker, QEventLoopLocker
*/
/*!
\fn QSignalBlocker::QSignalBlocker(QObject *object)
Constructor. Calls \a{object}->blockSignals(true).
*/
/*!
\fn QSignalBlocker::QSignalBlocker(QObject &object)
\overload
Calls \a{object}.blockSignals(true).
*/
/*!
\fn QSignalBlocker::QSignalBlocker(QSignalBlocker &&other)
Move-constructs a signal blocker from \a other. \a other will have
a no-op destructor, while repsonsibility for restoring the
QObject::signalsBlocked() state is transferred to the new object.
*/
/*!
\fn QSignalBlocker &QSignalBlocker::operator=(QSignalBlocker &&other)
Move-assigns this signal blocker from \a other. \a other will have
a no-op destructor, while repsonsibility for restoring the
QObject::signalsBlocked() state is transferred to this object.
The object's signals this signal blocker was blocking prior to
being moved to, if any, are unblocked \e except in the case where
both instances block the same object's signals and \c *this is
unblocked while \a other is not, at the time of the move.
*/
/*!
\fn QSignalBlocker::~QSignalBlocker()
Destructor. Restores the QObject::signalsBlocked() state to what it
was before the constructor ran, unless unblock() has been called
without a following reblock(), in which case it does nothing.
*/
/*!
\fn void QSignalBlocker::reblock()
Re-blocks signals after a previous unblock().
The numbers of reblock() and unblock() calls are not counted, so
every reblock() undoes any number of unblock() calls.
*/
/*!
\fn void QSignalBlocker::unblock()
Temporarily restores the QObject::signalsBlocked() state to what
it was before this QSignaBlocker's constructor ran. To undo, use
reblock().
The numbers of reblock() and unblock() calls are not counted, so
every unblock() undoes any number of reblock() calls.
*/
/*!
\class QObject
\inmodule QtCore
\brief The QObject class is the base class of all Qt objects.
\ingroup objectmodel
\reentrant
QObject is the heart of the Qt \l{Object Model}. The central
feature in this model is a very powerful mechanism for seamless
object communication called \l{signals and slots}. You can
connect a signal to a slot with connect() and destroy the
connection with disconnect(). To avoid never ending notification
loops you can temporarily block signals with blockSignals(). The
protected functions connectNotify() and disconnectNotify() make
it possible to track connections.
QObjects organize themselves in \l {Object Trees & Ownership}
{object trees}. When you create a QObject with another object as
parent, the object will automatically add itself to the parent's
children() list. The parent takes ownership of the object; i.e.,
it will automatically delete its children in its destructor. You
can look for an object by name and optionally type using
findChild() or findChildren().
Every object has an objectName() and its class name can be found
via the corresponding metaObject() (see QMetaObject::className()).
You can determine whether the object's class inherits another
class in the QObject inheritance hierarchy by using the
inherits() function.
When an object is deleted, it emits a destroyed() signal. You can
catch this signal to avoid dangling references to QObjects.
QObjects can receive events through event() and filter the events
of other objects. See installEventFilter() and eventFilter() for
details. A convenience handler, childEvent(), can be reimplemented
to catch child events.
Last but not least, QObject provides the basic timer support in
Qt; see QTimer for high-level support for timers.
Notice that the Q_OBJECT macro is mandatory for any object that
implements signals, slots or properties. You also need to run the
\l{moc}{Meta Object Compiler} on the source file. We strongly
recommend the use of this macro in all subclasses of QObject
regardless of whether or not they actually use signals, slots and
properties, since failure to do so may lead certain functions to
exhibit strange behavior.
All Qt widgets inherit QObject. The convenience function
isWidgetType() returns whether an object is actually a widget. It
is much faster than
\l{qobject_cast()}{qobject_cast}<QWidget *>(\e{obj}) or
\e{obj}->\l{inherits()}{inherits}("QWidget").
Some QObject functions, e.g. children(), return a QObjectList.
QObjectList is a typedef for QList<QObject *>.
\section1 Thread Affinity
A QObject instance is said to have a \e{thread affinity}, or that
it \e{lives} in a certain thread. When a QObject receives a
\l{Qt::QueuedConnection}{queued signal} or a \l{The Event
System#Sending Events}{posted event}, the slot or event handler
will run in the thread that the object lives in.
\note If a QObject has no thread affinity (that is, if thread()
returns zero), or if it lives in a thread that has no running event
loop, then it cannot receive queued signals or posted events.
By default, a QObject lives in the thread in which it is created.
An object's thread affinity can be queried using thread() and
changed using moveToThread().
All QObjects must live in the same thread as their parent. Consequently:
\list
\li setParent() will fail if the two QObjects involved live in
different threads.
\li When a QObject is moved to another thread, all its children
will be automatically moved too.
\li moveToThread() will fail if the QObject has a parent.
\li If QObjects are created within QThread::run(), they cannot
become children of the QThread object because the QThread does
not live in the thread that calls QThread::run().
\endlist
\note A QObject's member variables \e{do not} automatically become
its children. The parent-child relationship must be set by either
passing a pointer to the child's \l{QObject()}{constructor}, or by
calling setParent(). Without this step, the object's member variables
will remain in the old thread when moveToThread() is called.
\target No copy constructor
\section1 No Copy Constructor or Assignment Operator
QObject has neither a copy constructor nor an assignment operator.
This is by design. Actually, they are declared, but in a
\c{private} section with the macro Q_DISABLE_COPY(). In fact, all
Qt classes derived from QObject (direct or indirect) use this
macro to declare their copy constructor and assignment operator to
be private. The reasoning is found in the discussion on
\l{Identity vs Value} {Identity vs Value} on the Qt \l{Object
Model} page.
The main consequence is that you should use pointers to QObject
(or to your QObject subclass) where you might otherwise be tempted
to use your QObject subclass as a value. For example, without a
copy constructor, you can't use a subclass of QObject as the value
to be stored in one of the container classes. You must store
pointers.
\section1 Auto-Connection
Qt's meta-object system provides a mechanism to automatically connect
signals and slots between QObject subclasses and their children. As long
as objects are defined with suitable object names, and slots follow a
simple naming convention, this connection can be performed at run-time
by the QMetaObject::connectSlotsByName() function.
\l uic generates code that invokes this function to enable
auto-connection to be performed between widgets on forms created
with \e{Qt Designer}. More information about using auto-connection with \e{Qt Designer} is
given in the \l{Using a Designer UI File in Your Application} section of
the \e{Qt Designer} manual.
\section1 Dynamic Properties
From Qt 4.2, dynamic properties can be added to and removed from QObject
instances at run-time. Dynamic properties do not need to be declared at
compile-time, yet they provide the same advantages as static properties
and are manipulated using the same API - using property() to read them
and setProperty() to write them.
From Qt 4.3, dynamic properties are supported by
\l{Qt Designer's Widget Editing Mode#The Property Editor}{Qt Designer},
and both standard Qt widgets and user-created forms can be given dynamic
properties.
\section1 Internationalization (I18n)
All QObject subclasses support Qt's translation features, making it possible
to translate an application's user interface into different languages.
To make user-visible text translatable, it must be wrapped in calls to
the tr() function. This is explained in detail in the
\l{Writing Source Code for Translation} document.
\sa QMetaObject, QPointer, QObjectCleanupHandler, Q_DISABLE_COPY()
\sa {Object Trees & Ownership}
*/
/*****************************************************************************
QObject member functions
*****************************************************************************/
// check the constructor's parent thread argument
static bool check_parent_thread(QObject *parent,
QThreadData *parentThreadData,
QThreadData *currentThreadData)
{
if (parent && parentThreadData != currentThreadData) {
QThread *parentThread = parentThreadData->thread;
QThread *currentThread = currentThreadData->thread;
qWarning("QObject: Cannot create children for a parent that is in a different thread.\n"
"(Parent is %s(%p), parent's thread is %s(%p), current thread is %s(%p)",
parent->metaObject()->className(),
parent,
parentThread ? parentThread->metaObject()->className() : "QThread",
parentThread,
currentThread ? currentThread->metaObject()->className() : "QThread",
currentThread);
return false;
}
return true;
}
/*!
Constructs an object with parent object \a parent.
The parent of an object may be viewed as the object's owner. For
instance, a \l{QDialog}{dialog box} is the parent of the \uicontrol{OK}
and \uicontrol{Cancel} buttons it contains.
The destructor of a parent object destroys all child objects.
Setting \a parent to 0 constructs an object with no parent. If the
object is a widget, it will become a top-level window.
\sa parent(), findChild(), findChildren()
*/
QObject::QObject(QObject *parent)
: d_ptr(new QObjectPrivate)
{
Q_D(QObject);
d_ptr->q_ptr = this;
d->threadData = (parent && !parent->thread()) ? parent->d_func()->threadData : QThreadData::current();
d->threadData->ref();
if (parent) {
QT_TRY {
if (!check_parent_thread(parent, parent ? parent->d_func()->threadData : 0, d->threadData))
parent = 0;
setParent(parent);
} QT_CATCH(...) {
d->threadData->deref();
QT_RETHROW;
}
}
#if QT_VERSION < 0x60000
qt_addObject(this);
#endif
if (Q_UNLIKELY(qtHookData[QHooks::AddQObject]))
reinterpret_cast<QHooks::AddQObjectCallback>(qtHookData[QHooks::AddQObject])(this);
Q_TRACE(QObject_ctor, this);
}
/*!
\internal
*/
QObject::QObject(QObjectPrivate &dd, QObject *parent)
: d_ptr(&dd)
{
Q_D(QObject);
d_ptr->q_ptr = this;
d->threadData = (parent && !parent->thread()) ? parent->d_func()->threadData : QThreadData::current();
d->threadData->ref();
if (parent) {
QT_TRY {
if (!check_parent_thread(parent, parent ? parent->d_func()->threadData : 0, d->threadData))
parent = 0;
if (d->isWidget) {
if (parent) {
d->parent = parent;
d->parent->d_func()->children.append(this);
}
// no events sent here, this is done at the end of the QWidget constructor
} else {
setParent(parent);
}
} QT_CATCH(...) {
d->threadData->deref();
QT_RETHROW;
}
}
#if QT_VERSION < 0x60000
qt_addObject(this);
#endif
if (Q_UNLIKELY(qtHookData[QHooks::AddQObject]))
reinterpret_cast<QHooks::AddQObjectCallback>(qtHookData[QHooks::AddQObject])(this);
Q_TRACE(QObject_ctor, this);
}
/*!
Destroys the object, deleting all its child objects.
All signals to and from the object are automatically disconnected, and
any pending posted events for the object are removed from the event
queue. However, it is often safer to use deleteLater() rather than
deleting a QObject subclass directly.
\warning All child objects are deleted. If any of these objects
are on the stack or global, sooner or later your program will
crash. We do not recommend holding pointers to child objects from
outside the parent. If you still do, the destroyed() signal gives
you an opportunity to detect when an object is destroyed.
\warning Deleting a QObject while pending events are waiting to
be delivered can cause a crash. You must not delete the QObject
directly if it exists in a different thread than the one currently
executing. Use deleteLater() instead, which will cause the event
loop to delete the object after all pending events have been
delivered to it.
\sa deleteLater()
*/
QObject::~QObject()
{
Q_D(QObject);
d->wasDeleted = true;
d->blockSig = 0; // unblock signals so we always emit destroyed()
QtSharedPointer::ExternalRefCountData *sharedRefcount = d->sharedRefcount.load();
if (sharedRefcount) {
if (sharedRefcount->strongref.load() > 0) {
qWarning("QObject: shared QObject was deleted directly. The program is malformed and may crash.");
// but continue deleting, it's too late to stop anyway
}
// indicate to all QWeakPointers that this QObject has now been deleted
sharedRefcount->strongref.store(0);
if (!sharedRefcount->weakref.deref())
delete sharedRefcount;
}
if (!d->isWidget && d->isSignalConnected(0)) {
emit destroyed(this);
}
if (d->declarativeData) {
if (static_cast<QAbstractDeclarativeDataImpl*>(d->declarativeData)->ownedByQml1) {
if (QAbstractDeclarativeData::destroyed_qml1)
QAbstractDeclarativeData::destroyed_qml1(d->declarativeData, this);
} else {
if (QAbstractDeclarativeData::destroyed)
QAbstractDeclarativeData::destroyed(d->declarativeData, this);
}
}
// set ref to zero to indicate that this object has been deleted
if (d->currentSender != 0)
d->currentSender->ref = 0;
d->currentSender = 0;
if (d->connectionLists || d->senders) {
QMutex *signalSlotMutex = signalSlotLock(this);
QMutexLocker locker(signalSlotMutex);
// disconnect all receivers
if (d->connectionLists) {
++d->connectionLists->inUse;
int connectionListsCount = d->connectionLists->count();
for (int signal = -1; signal < connectionListsCount; ++signal) {
QObjectPrivate::ConnectionList &connectionList =
(*d->connectionLists)[signal];
while (QObjectPrivate::Connection *c = connectionList.first) {
if (!c->receiver) {
connectionList.first = c->nextConnectionList;
c->deref();
continue;
}
QMutex *m = signalSlotLock(c->receiver);
bool needToUnlock = QOrderedMutexLocker::relock(signalSlotMutex, m);
if (c->receiver) {
*c->prev = c->next;
if (c->next) c->next->prev = c->prev;
}
c->receiver = 0;
if (needToUnlock)
m->unlock();
connectionList.first = c->nextConnectionList;
// The destroy operation must happen outside the lock
if (c->isSlotObject) {
c->isSlotObject = false;
locker.unlock();
c->slotObj->destroyIfLastRef();
locker.relock();
}
c->deref();
}
}
if (!--d->connectionLists->inUse) {
delete d->connectionLists;
} else {
d->connectionLists->orphaned = true;
}
d->connectionLists = 0;
}
/* Disconnect all senders:
* This loop basically just does
* for (node = d->senders; node; node = node->next) { ... }
*
* We need to temporarily unlock the receiver mutex to destroy the functors or to lock the
* sender's mutex. And when the mutex is released, node->next might be destroyed by another
* thread. That's why we set node->prev to &node, that way, if node is destroyed, node will
* be updated.
*/
QObjectPrivate::Connection *node = d->senders;
while (node) {
QObject *sender = node->sender;
// Send disconnectNotify before removing the connection from sender's connection list.
// This ensures any eventual destructor of sender will block on getting receiver's lock
// and not finish until we release it.
sender->disconnectNotify(QMetaObjectPrivate::signal(sender->metaObject(), node->signal_index));
QMutex *m = signalSlotLock(sender);
node->prev = &node;
bool needToUnlock = QOrderedMutexLocker::relock(signalSlotMutex, m);
//the node has maybe been removed while the mutex was unlocked in relock?
if (!node || node->sender != sender) {
// We hold the wrong mutex
Q_ASSERT(needToUnlock);
m->unlock();
continue;
}
node->receiver = 0;
QObjectConnectionListVector *senderLists = sender->d_func()->connectionLists;
if (senderLists)
senderLists->dirty = true;
QtPrivate::QSlotObjectBase *slotObj = nullptr;
if (node->isSlotObject) {
slotObj = node->slotObj;
node->isSlotObject = false;
}
node = node->next;
if (needToUnlock)
m->unlock();
if (slotObj) {
if (node)
node->prev = &node;
locker.unlock();
slotObj->destroyIfLastRef();
locker.relock();
}
}
}
if (!d->children.isEmpty())
d->deleteChildren();
#if QT_VERSION < 0x60000
qt_removeObject(this);
#endif
if (Q_UNLIKELY(qtHookData[QHooks::RemoveQObject]))
reinterpret_cast<QHooks::RemoveQObjectCallback>(qtHookData[QHooks::RemoveQObject])(this);
Q_TRACE(QObject_dtor, this);
if (d->parent) // remove it from parent object
d->setParent_helper(0);
}
QObjectPrivate::Connection::~Connection()
{
if (ownArgumentTypes) {
const int *v = argumentTypes.load();
if (v != &DIRECT_CONNECTION_ONLY)
delete [] v;
}
if (isSlotObject)
slotObj->destroyIfLastRef();
}
/*!
\fn const QMetaObject *QObject::metaObject() const
Returns a pointer to the meta-object of this object.
A meta-object contains information about a class that inherits
QObject, e.g. class name, superclass name, properties, signals and
slots. Every QObject subclass that contains the Q_OBJECT macro will have a
meta-object.
The meta-object information is required by the signal/slot
connection mechanism and the property system. The inherits()
function also makes use of the meta-object.
If you have no pointer to an actual object instance but still
want to access the meta-object of a class, you can use \l
staticMetaObject.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 1
\sa staticMetaObject
*/
/*!
\variable QObject::staticMetaObject
This variable stores the meta-object for the class.
A meta-object contains information about a class that inherits
QObject, e.g. class name, superclass name, properties, signals and
slots. Every class that contains the Q_OBJECT macro will also have
a meta-object.
The meta-object information is required by the signal/slot
connection mechanism and the property system. The inherits()
function also makes use of the meta-object.
If you have a pointer to an object, you can use metaObject() to
retrieve the meta-object associated with that object.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 2
\sa metaObject()
*/
/*!
\fn template <class T> T qobject_cast(QObject *object)
\fn template <class T> T qobject_cast(const QObject *object)
\relates QObject
Returns the given \a object cast to type T if the object is of type
T (or of a subclass); otherwise returns 0. If \a object is 0 then
it will also return 0.
The class T must inherit (directly or indirectly) QObject and be
declared with the \l Q_OBJECT macro.
A class is considered to inherit itself.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 3
The qobject_cast() function behaves similarly to the standard C++
\c dynamic_cast(), with the advantages that it doesn't require
RTTI support and it works across dynamic library boundaries.
qobject_cast() can also be used in conjunction with interfaces;
see the \l{tools/plugandpaint/app}{Plug & Paint} example for details.
\warning If T isn't declared with the Q_OBJECT macro, this
function's return value is undefined.
\sa QObject::inherits()
*/
/*!
\fn bool QObject::inherits(const char *className) const
Returns \c true if this object is an instance of a class that
inherits \a className or a QObject subclass that inherits \a
className; otherwise returns \c false.
A class is considered to inherit itself.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 4
If you need to determine whether an object is an instance of a particular
class for the purpose of casting it, consider using qobject_cast<Type *>(object)
instead.
\sa metaObject(), qobject_cast()
*/
/*!
\property QObject::objectName
\brief the name of this object
You can find an object by name (and type) using findChild().
You can find a set of objects with findChildren().
\snippet code/src_corelib_kernel_qobject.cpp 5
By default, this property contains an empty string.
\sa metaObject(), QMetaObject::className()
*/
QString QObject::objectName() const
{
Q_D(const QObject);
return d->extraData ? d->extraData->objectName : QString();
}
/*
Sets the object's name to \a name.
*/
void QObject::setObjectName(const QString &name)
{
Q_D(QObject);
if (!d->extraData)
d->extraData = new QObjectPrivate::ExtraData;
if (d->extraData->objectName != name) {
d->extraData->objectName = name;
emit objectNameChanged(d->extraData->objectName, QPrivateSignal());
}
}
/*! \fn void QObject::objectNameChanged(const QString &objectName)
This signal is emitted after the object's name has been changed. The new object name is passed as \a objectName.
\sa QObject::objectName
*/
/*!
\fn bool QObject::isWidgetType() const
Returns \c true if the object is a widget; otherwise returns \c false.
Calling this function is equivalent to calling
\c{inherits("QWidget")}, except that it is much faster.
*/
/*!
\fn bool QObject::isWindowType() const
Returns \c true if the object is a window; otherwise returns \c false.
Calling this function is equivalent to calling
\c{inherits("QWindow")}, except that it is much faster.
*/
/*!
This virtual function receives events to an object and should
return true if the event \a e was recognized and processed.
The event() function can be reimplemented to customize the
behavior of an object.
Make sure you call the parent event class implementation
for all the events you did not handle.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 52
\sa installEventFilter(), timerEvent(), QCoreApplication::sendEvent(),
QCoreApplication::postEvent()
*/
bool QObject::event(QEvent *e)
{
switch (e->type()) {
case QEvent::Timer:
timerEvent((QTimerEvent*)e);
break;
case QEvent::ChildAdded:
case QEvent::ChildPolished:
case QEvent::ChildRemoved:
childEvent((QChildEvent*)e);
break;
case QEvent::DeferredDelete:
qDeleteInEventHandler(this);
break;
case QEvent::MetaCall:
{
QMetaCallEvent *mce = static_cast<QMetaCallEvent*>(e);
QConnectionSenderSwitcher sw(this, const_cast<QObject*>(mce->sender()), mce->signalId());
mce->placeMetaCall(this);
break;
}
case QEvent::ThreadChange: {
Q_D(QObject);
QThreadData *threadData = d->threadData;
QAbstractEventDispatcher *eventDispatcher = threadData->eventDispatcher.load();
if (eventDispatcher) {
QList<QAbstractEventDispatcher::TimerInfo> timers = eventDispatcher->registeredTimers(this);
if (!timers.isEmpty()) {
// do not to release our timer ids back to the pool (since the timer ids are moving to a new thread).
eventDispatcher->unregisterTimers(this);
QMetaObject::invokeMethod(this, "_q_reregisterTimers", Qt::QueuedConnection,
Q_ARG(void*, (new QList<QAbstractEventDispatcher::TimerInfo>(timers))));
}
}
break;
}
default:
if (e->type() >= QEvent::User) {
customEvent(e);
break;
}
return false;
}
return true;
}
/*!
\fn void QObject::timerEvent(QTimerEvent *event)
This event handler can be reimplemented in a subclass to receive
timer events for the object.
QTimer provides a higher-level interface to the timer
functionality, and also more general information about timers. The
timer event is passed in the \a event parameter.
\sa startTimer(), killTimer(), event()
*/
void QObject::timerEvent(QTimerEvent *)
{
}
/*!
This event handler can be reimplemented in a subclass to receive
child events. The event is passed in the \a event parameter.
QEvent::ChildAdded and QEvent::ChildRemoved events are sent to
objects when children are added or removed. In both cases you can
only rely on the child being a QObject, or if isWidgetType()
returns \c true, a QWidget. (This is because, in the
\l{QEvent::ChildAdded}{ChildAdded} case, the child is not yet
fully constructed, and in the \l{QEvent::ChildRemoved}{ChildRemoved}
case it might have been destructed already).
QEvent::ChildPolished events are sent to widgets when children
are polished, or when polished children are added. If you receive
a child polished event, the child's construction is usually
completed. However, this is not guaranteed, and multiple polish
events may be delivered during the execution of a widget's
constructor.
For every child widget, you receive one
\l{QEvent::ChildAdded}{ChildAdded} event, zero or more
\l{QEvent::ChildPolished}{ChildPolished} events, and one
\l{QEvent::ChildRemoved}{ChildRemoved} event.
The \l{QEvent::ChildPolished}{ChildPolished} event is omitted if
a child is removed immediately after it is added. If a child is
polished several times during construction and destruction, you
may receive several child polished events for the same child,
each time with a different virtual table.
\sa event()
*/
void QObject::childEvent(QChildEvent * /* event */)
{
}
/*!
This event handler can be reimplemented in a subclass to receive
custom events. Custom events are user-defined events with a type
value at least as large as the QEvent::User item of the
QEvent::Type enum, and is typically a QEvent subclass. The event
is passed in the \a event parameter.
\sa event(), QEvent
*/
void QObject::customEvent(QEvent * /* event */)
{
}
/*!
Filters events if this object has been installed as an event
filter for the \a watched object.
In your reimplementation of this function, if you want to filter
the \a event out, i.e. stop it being handled further, return
true; otherwise return false.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 6
Notice in the example above that unhandled events are passed to
the base class's eventFilter() function, since the base class
might have reimplemented eventFilter() for its own internal
purposes.
Some events, such as \l QEvent::ShortcutOverride must be explicitly
accepted (by calling \l {QEvent::}{accept()} on them) in order to prevent
propagation.
\warning If you delete the receiver object in this function, be
sure to return true. Otherwise, Qt will forward the event to the
deleted object and the program might crash.
\sa installEventFilter()
*/
bool QObject::eventFilter(QObject * /* watched */, QEvent * /* event */)
{
return false;
}
/*!
\fn bool QObject::signalsBlocked() const
Returns \c true if signals are blocked; otherwise returns \c false.
Signals are not blocked by default.
\sa blockSignals(), QSignalBlocker
*/
/*!
If \a block is true, signals emitted by this object are blocked
(i.e., emitting a signal will not invoke anything connected to it).
If \a block is false, no such blocking will occur.
The return value is the previous value of signalsBlocked().
Note that the destroyed() signal will be emitted even if the signals
for this object have been blocked.
Signals emitted while being blocked are not buffered.
\sa signalsBlocked(), QSignalBlocker
*/
bool QObject::blockSignals(bool block) Q_DECL_NOTHROW
{
Q_D(QObject);
bool previous = d->blockSig;
d->blockSig = block;
return previous;
}
/*!
Returns the thread in which the object lives.
\sa moveToThread()
*/
QThread *QObject::thread() const
{
return d_func()->threadData->thread;
}
/*!
Changes the thread affinity for this object and its children. The
object cannot be moved if it has a parent. Event processing will
continue in the \a targetThread.
To move an object to the main thread, use QApplication::instance()
to retrieve a pointer to the current application, and then use
QApplication::thread() to retrieve the thread in which the
application lives. For example:
\snippet code/src_corelib_kernel_qobject.cpp 7
If \a targetThread is \nullptr, all event processing for this object
and its children stops, as they are no longer associated with any
thread.
Note that all active timers for the object will be reset. The
timers are first stopped in the current thread and restarted (with
the same interval) in the \a targetThread. As a result, constantly
moving an object between threads can postpone timer events
indefinitely.
A QEvent::ThreadChange event is sent to this object just before
the thread affinity is changed. You can handle this event to
perform any special processing. Note that any new events that are
posted to this object will be handled in the \a targetThread,
provided it is non-null: when it is \nullptr, no event processing
for this object or its children can happen, as they are no longer
associated with any thread.
\warning This function is \e not thread-safe; the current thread
must be same as the current thread affinity. In other words, this
function can only "push" an object from the current thread to
another thread, it cannot "pull" an object from any arbitrary
thread to the current thread. There is one exception to this rule
however: objects with no thread affinity can be "pulled" to the
current thread.
\sa thread()
*/
void QObject::moveToThread(QThread *targetThread)
{
Q_D(QObject);
if (d->threadData->thread == targetThread) {
// object is already in this thread
return;
}
if (d->parent != 0) {
qWarning("QObject::moveToThread: Cannot move objects with a parent");
return;
}
if (d->isWidget) {
qWarning("QObject::moveToThread: Widgets cannot be moved to a new thread");
return;
}
QThreadData *currentData = QThreadData::current();
QThreadData *targetData = targetThread ? QThreadData::get2(targetThread) : nullptr;
if (d->threadData->thread == 0 && currentData == targetData) {
// one exception to the rule: we allow moving objects with no thread affinity to the current thread
currentData = d->threadData;
} else if (d->threadData != currentData) {
qWarning("QObject::moveToThread: Current thread (%p) is not the object's thread (%p).\n"
"Cannot move to target thread (%p)\n",
currentData->thread.load(), d->threadData->thread.load(), targetData ? targetData->thread.load() : nullptr);
#ifdef Q_OS_MAC
qWarning("You might be loading two sets of Qt binaries into the same process. "
"Check that all plugins are compiled against the right Qt binaries. Export "
"DYLD_PRINT_LIBRARIES=1 and check that only one set of binaries are being loaded.");
#endif
return;
}
// prepare to move
d->moveToThread_helper();
if (!targetData)
targetData = new QThreadData(0);
QOrderedMutexLocker locker(¤tData->postEventList.mutex,
&targetData->postEventList.mutex);
// keep currentData alive (since we've got it locked)
currentData->ref();
// move the object
d_func()->setThreadData_helper(currentData, targetData);
locker.unlock();
// now currentData can commit suicide if it wants to
currentData->deref();
}
void QObjectPrivate::moveToThread_helper()
{
Q_Q(QObject);
QEvent e(QEvent::ThreadChange);
QCoreApplication::sendEvent(q, &e);
for (int i = 0; i < children.size(); ++i) {
QObject *child = children.at(i);
child->d_func()->moveToThread_helper();
}
}
void QObjectPrivate::setThreadData_helper(QThreadData *currentData, QThreadData *targetData)
{
Q_Q(QObject);
// move posted events
int eventsMoved = 0;
for (int i = 0; i < currentData->postEventList.size(); ++i) {
const QPostEvent &pe = currentData->postEventList.at(i);
if (!pe.event)
continue;
if (pe.receiver == q) {
// move this post event to the targetList
targetData->postEventList.addEvent(pe);
const_cast<QPostEvent &>(pe).event = 0;
++eventsMoved;
}
}
if (eventsMoved > 0 && targetData->hasEventDispatcher()) {
targetData->canWait = false;
targetData->eventDispatcher.load()->wakeUp();
}
// the current emitting thread shouldn't restore currentSender after calling moveToThread()
if (currentSender)
currentSender->ref = 0;
currentSender = 0;
// set new thread data
targetData->ref();
threadData->deref();
threadData = targetData;
for (int i = 0; i < children.size(); ++i) {
QObject *child = children.at(i);
child->d_func()->setThreadData_helper(currentData, targetData);
}
}
void QObjectPrivate::_q_reregisterTimers(void *pointer)
{
Q_Q(QObject);
QList<QAbstractEventDispatcher::TimerInfo> *timerList = reinterpret_cast<QList<QAbstractEventDispatcher::TimerInfo> *>(pointer);
QAbstractEventDispatcher *eventDispatcher = threadData->eventDispatcher.load();
for (int i = 0; i < timerList->size(); ++i) {
const QAbstractEventDispatcher::TimerInfo &ti = timerList->at(i);
eventDispatcher->registerTimer(ti.timerId, ti.interval, ti.timerType, q);
}
delete timerList;
}
//
// The timer flag hasTimer is set when startTimer is called.
// It is not reset when killing the timer because more than
// one timer might be active.
//
/*!
Starts a timer and returns a timer identifier, or returns zero if
it could not start a timer.
A timer event will occur every \a interval milliseconds until
killTimer() is called. If \a interval is 0, then the timer event
occurs once every time there are no more window system events to
process.
The virtual timerEvent() function is called with the QTimerEvent
event parameter class when a timer event occurs. Reimplement this
function to get timer events.
If multiple timers are running, the QTimerEvent::timerId() can be
used to find out which timer was activated.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 8
Note that QTimer's accuracy depends on the underlying operating system and
hardware. The \a timerType argument allows you to customize the accuracy of
the timer. See Qt::TimerType for information on the different timer types.
Most platforms support an accuracy of 20 milliseconds; some provide more.
If Qt is unable to deliver the requested number of timer events, it will
silently discard some.
The QTimer class provides a high-level programming interface with
single-shot timers and timer signals instead of events. There is
also a QBasicTimer class that is more lightweight than QTimer and
less clumsy than using timer IDs directly.
\sa timerEvent(), killTimer(), QTimer::singleShot()
*/
int QObject::startTimer(int interval, Qt::TimerType timerType)
{
Q_D(QObject);
if (Q_UNLIKELY(interval < 0)) {
qWarning("QObject::startTimer: Timers cannot have negative intervals");
return 0;
}
if (Q_UNLIKELY(!d->threadData->hasEventDispatcher())) {
qWarning("QObject::startTimer: Timers can only be used with threads started with QThread");
return 0;
}
if (Q_UNLIKELY(thread() != QThread::currentThread())) {
qWarning("QObject::startTimer: Timers cannot be started from another thread");
return 0;
}
int timerId = d->threadData->eventDispatcher.load()->registerTimer(interval, timerType, this);
if (!d->extraData)
d->extraData = new QObjectPrivate::ExtraData;
d->extraData->runningTimers.append(timerId);
return timerId;
}
/*!
\since 5.9
\overload
\fn int QObject::startTimer(std::chrono::milliseconds time, Qt::TimerType timerType)
Starts a timer and returns a timer identifier, or returns zero if
it could not start a timer.
A timer event will occur every \a time interval until killTimer()
is called. If \a time is equal to \c{std::chrono::duration::zero()},
then the timer event occurs once every time there are no more window
system events to process.
The virtual timerEvent() function is called with the QTimerEvent
event parameter class when a timer event occurs. Reimplement this
function to get timer events.
If multiple timers are running, the QTimerEvent::timerId() can be
used to find out which timer was activated.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 8
Note that QTimer's accuracy depends on the underlying operating system and
hardware. The \a timerType argument allows you to customize the accuracy of
the timer. See Qt::TimerType for information on the different timer types.
Most platforms support an accuracy of 20 milliseconds; some provide more.
If Qt is unable to deliver the requested number of timer events, it will
silently discard some.
The QTimer class provides a high-level programming interface with
single-shot timers and timer signals instead of events. There is
also a QBasicTimer class that is more lightweight than QTimer and
less clumsy than using timer IDs directly.
\sa timerEvent(), killTimer(), QTimer::singleShot()
*/
/*!
Kills the timer with timer identifier, \a id.
The timer identifier is returned by startTimer() when a timer
event is started.
\sa timerEvent(), startTimer()
*/
void QObject::killTimer(int id)
{
Q_D(QObject);
if (Q_UNLIKELY(thread() != QThread::currentThread())) {
qWarning("QObject::killTimer: Timers cannot be stopped from another thread");
return;
}
if (id) {
int at = d->extraData ? d->extraData->runningTimers.indexOf(id) : -1;
if (at == -1) {
// timer isn't owned by this object
qWarning("QObject::killTimer(): Error: timer id %d is not valid for object %p (%s, %s), timer has not been killed",
id,
this,
metaObject()->className(),
qPrintable(objectName()));
return;
}
if (d->threadData->hasEventDispatcher())
d->threadData->eventDispatcher.load()->unregisterTimer(id);
d->extraData->runningTimers.remove(at);
QAbstractEventDispatcherPrivate::releaseTimerId(id);
}
}
/*!
\fn QObject *QObject::parent() const
Returns a pointer to the parent object.
\sa children()
*/
/*!
\fn const QObjectList &QObject::children() const
Returns a list of child objects.
The QObjectList class is defined in the \c{<QObject>} header
file as the following:
\quotefromfile kernel/qobject.h
\skipto /typedef .*QObjectList/
\printuntil QObjectList
The first child added is the \l{QList::first()}{first} object in
the list and the last child added is the \l{QList::last()}{last}
object in the list, i.e. new children are appended at the end.
Note that the list order changes when QWidget children are
\l{QWidget::raise()}{raised} or \l{QWidget::lower()}{lowered}. A
widget that is raised becomes the last object in the list, and a
widget that is lowered becomes the first object in the list.
\sa findChild(), findChildren(), parent(), setParent()
*/
/*!
\fn template<typename T> T *QObject::findChild(const QString &name, Qt::FindChildOptions options) const
Returns the child of this object that can be cast into type T and
that is called \a name, or 0 if there is no such object.
Omitting the \a name argument causes all object names to be matched.
The search is performed recursively, unless \a options specifies the
option FindDirectChildrenOnly.
If there is more than one child matching the search, the most
direct ancestor is returned. If there are several direct
ancestors, it is undefined which one will be returned. In that
case, findChildren() should be used.
This example returns a child \c{QPushButton} of \c{parentWidget}
named \c{"button1"}, even if the button isn't a direct child of
the parent:
\snippet code/src_corelib_kernel_qobject.cpp 10
This example returns a \c{QListWidget} child of \c{parentWidget}:
\snippet code/src_corelib_kernel_qobject.cpp 11
This example returns a child \c{QPushButton} of \c{parentWidget}
(its direct parent) named \c{"button1"}:
\snippet code/src_corelib_kernel_qobject.cpp 41
This example returns a \c{QListWidget} child of \c{parentWidget},
its direct parent:
\snippet code/src_corelib_kernel_qobject.cpp 42
\sa findChildren()
*/
/*!
\fn template<typename T> QList<T> QObject::findChildren(const QString &name, Qt::FindChildOptions options) const
Returns all children of this object with the given \a name that can be
cast to type T, or an empty list if there are no such objects.
Omitting the \a name argument causes all object names to be matched.
The search is performed recursively, unless \a options specifies the
option FindDirectChildrenOnly.
The following example shows how to find a list of child \c{QWidget}s of
the specified \c{parentWidget} named \c{widgetname}:
\snippet code/src_corelib_kernel_qobject.cpp 12
This example returns all \c{QPushButton}s that are children of \c{parentWidget}:
\snippet code/src_corelib_kernel_qobject.cpp 13
This example returns all \c{QPushButton}s that are immediate children of \c{parentWidget}:
\snippet code/src_corelib_kernel_qobject.cpp 43
\sa findChild()
*/
/*!
\fn template<typename T> QList<T> QObject::findChildren(const QRegExp ®Exp, Qt::FindChildOptions options) const
\overload findChildren()
Returns the children of this object that can be cast to type T
and that have names matching the regular expression \a regExp,
or an empty list if there are no such objects.
The search is performed recursively, unless \a options specifies the
option FindDirectChildrenOnly.
*/
/*!
\fn QList<T> QObject::findChildren(const QRegularExpression &re, Qt::FindChildOptions options) const
\overload findChildren()
\since 5.0
Returns the children of this object that can be cast to type T
and that have names matching the regular expression \a re,
or an empty list if there are no such objects.
The search is performed recursively, unless \a options specifies the
option FindDirectChildrenOnly.
*/
/*!
\fn template<typename T> T qFindChild(const QObject *obj, const QString &name)
\relates QObject
\overload qFindChildren()
\obsolete
This function is equivalent to
\a{obj}->\l{QObject::findChild()}{findChild}<T>(\a name).
\note This function was provided as a workaround for MSVC 6
which did not support member template functions. It is advised
to use the other form in new code.
\sa QObject::findChild()
*/
/*!
\fn template<typename T> QList<T> qFindChildren(const QObject *obj, const QString &name)
\relates QObject
\overload qFindChildren()
\obsolete
This function is equivalent to
\a{obj}->\l{QObject::findChildren()}{findChildren}<T>(\a name).
\note This function was provided as a workaround for MSVC 6
which did not support member template functions. It is advised
to use the other form in new code.
\sa QObject::findChildren()
*/
/*!
\fn template<typename T> QList<T> qFindChildren(const QObject *obj, const QRegExp ®Exp)
\relates QObject
\overload qFindChildren()
This function is equivalent to
\a{obj}->\l{QObject::findChildren()}{findChildren}<T>(\a regExp).
\note This function was provided as a workaround for MSVC 6
which did not support member template functions. It is advised
to use the other form in new code.
\sa QObject::findChildren()
*/
/*!
\internal
*/
void qt_qFindChildren_helper(const QObject *parent, const QString &name,
const QMetaObject &mo, QList<void*> *list, Qt::FindChildOptions options)
{
if (!parent || !list)
return;
const QObjectList &children = parent->children();
QObject *obj;
for (int i = 0; i < children.size(); ++i) {
obj = children.at(i);
if (mo.cast(obj)) {
if (name.isNull() || obj->objectName() == name)
list->append(obj);
}
if (options & Qt::FindChildrenRecursively)
qt_qFindChildren_helper(obj, name, mo, list, options);
}
}
#ifndef QT_NO_REGEXP
/*!
\internal
*/
void qt_qFindChildren_helper(const QObject *parent, const QRegExp &re,
const QMetaObject &mo, QList<void*> *list, Qt::FindChildOptions options)
{
if (!parent || !list)
return;
const QObjectList &children = parent->children();
QRegExp reCopy = re;
QObject *obj;
for (int i = 0; i < children.size(); ++i) {
obj = children.at(i);
if (mo.cast(obj) && reCopy.indexIn(obj->objectName()) != -1)
list->append(obj);
if (options & Qt::FindChildrenRecursively)
qt_qFindChildren_helper(obj, re, mo, list, options);
}
}
#endif // QT_NO_REGEXP
#if QT_CONFIG(regularexpression)
/*!
\internal
*/
void qt_qFindChildren_helper(const QObject *parent, const QRegularExpression &re,
const QMetaObject &mo, QList<void*> *list, Qt::FindChildOptions options)
{
if (!parent || !list)
return;
const QObjectList &children = parent->children();
QObject *obj;
for (int i = 0; i < children.size(); ++i) {
obj = children.at(i);
if (mo.cast(obj)) {
QRegularExpressionMatch m = re.match(obj->objectName());
if (m.hasMatch())
list->append(obj);
}
if (options & Qt::FindChildrenRecursively)
qt_qFindChildren_helper(obj, re, mo, list, options);
}
}
#endif // QT_CONFIG(regularexpression)
/*!
\internal
*/
QObject *qt_qFindChild_helper(const QObject *parent, const QString &name, const QMetaObject &mo, Qt::FindChildOptions options)
{
if (!parent)
return 0;
const QObjectList &children = parent->children();
QObject *obj;
int i;
for (i = 0; i < children.size(); ++i) {
obj = children.at(i);
if (mo.cast(obj) && (name.isNull() || obj->objectName() == name))
return obj;
}
if (options & Qt::FindChildrenRecursively) {
for (i = 0; i < children.size(); ++i) {
obj = qt_qFindChild_helper(children.at(i), name, mo, options);
if (obj)
return obj;
}
}
return 0;
}
/*!
Makes the object a child of \a parent.
\sa parent(), children()
*/
void QObject::setParent(QObject *parent)
{
Q_D(QObject);
Q_ASSERT(!d->isWidget);
d->setParent_helper(parent);
}
void QObjectPrivate::deleteChildren()
{
Q_ASSERT_X(!isDeletingChildren, "QObjectPrivate::deleteChildren()", "isDeletingChildren already set, did this function recurse?");
isDeletingChildren = true;
// delete children objects
// don't use qDeleteAll as the destructor of the child might
// delete siblings
for (int i = 0; i < children.count(); ++i) {
currentChildBeingDeleted = children.at(i);
children[i] = 0;
delete currentChildBeingDeleted;
}
children.clear();
currentChildBeingDeleted = 0;
isDeletingChildren = false;
}
void QObjectPrivate::setParent_helper(QObject *o)
{
Q_Q(QObject);
if (o == parent)
return;
if (parent) {
QObjectPrivate *parentD = parent->d_func();
if (parentD->isDeletingChildren && wasDeleted
&& parentD->currentChildBeingDeleted == q) {
// don't do anything since QObjectPrivate::deleteChildren() already
// cleared our entry in parentD->children.
} else {
const int index = parentD->children.indexOf(q);
if (parentD->isDeletingChildren) {
parentD->children[index] = 0;
} else {
parentD->children.removeAt(index);
if (sendChildEvents && parentD->receiveChildEvents) {
QChildEvent e(QEvent::ChildRemoved, q);
QCoreApplication::sendEvent(parent, &e);
}
}
}
}
parent = o;
if (parent) {
// object hierarchies are constrained to a single thread
if (threadData != parent->d_func()->threadData) {
qWarning("QObject::setParent: Cannot set parent, new parent is in a different thread");
parent = 0;
return;
}
parent->d_func()->children.append(q);
if(sendChildEvents && parent->d_func()->receiveChildEvents) {
if (!isWidget) {
QChildEvent e(QEvent::ChildAdded, q);
QCoreApplication::sendEvent(parent, &e);
}
}
}
if (!wasDeleted && !isDeletingChildren && declarativeData && QAbstractDeclarativeData::parentChanged)
QAbstractDeclarativeData::parentChanged(declarativeData, q, o);
}
/*!
\fn void QObject::installEventFilter(QObject *filterObj)
Installs an event filter \a filterObj on this object. For example:
\snippet code/src_corelib_kernel_qobject.cpp 14
An event filter is an object that receives all events that are
sent to this object. The filter can either stop the event or
forward it to this object. The event filter \a filterObj receives
events via its eventFilter() function. The eventFilter() function
must return true if the event should be filtered, (i.e. stopped);
otherwise it must return false.
If multiple event filters are installed on a single object, the
filter that was installed last is activated first.
Here's a \c KeyPressEater class that eats the key presses of its
monitored objects:
\snippet code/src_corelib_kernel_qobject.cpp 15
And here's how to install it on two widgets:
\snippet code/src_corelib_kernel_qobject.cpp 16
The QShortcut class, for example, uses this technique to intercept
shortcut key presses.
\warning If you delete the receiver object in your eventFilter()
function, be sure to return true. If you return false, Qt sends
the event to the deleted object and the program will crash.
Note that the filtering object must be in the same thread as this
object. If \a filterObj is in a different thread, this function does
nothing. If either \a filterObj or this object are moved to a different
thread after calling this function, the event filter will not be
called until both objects have the same thread affinity again (it
is \e not removed).
\sa removeEventFilter(), eventFilter(), event()
*/
void QObject::installEventFilter(QObject *obj)
{
Q_D(QObject);
if (!obj)
return;
if (d->threadData != obj->d_func()->threadData) {
qWarning("QObject::installEventFilter(): Cannot filter events for objects in a different thread.");
return;
}
if (!d->extraData)
d->extraData = new QObjectPrivate::ExtraData;
// clean up unused items in the list
d->extraData->eventFilters.removeAll((QObject*)0);
d->extraData->eventFilters.removeAll(obj);
d->extraData->eventFilters.prepend(obj);
}
/*!
Removes an event filter object \a obj from this object. The
request is ignored if such an event filter has not been installed.
All event filters for this object are automatically removed when
this object is destroyed.
It is always safe to remove an event filter, even during event
filter activation (i.e. from the eventFilter() function).
\sa installEventFilter(), eventFilter(), event()
*/
void QObject::removeEventFilter(QObject *obj)
{
Q_D(QObject);
if (d->extraData) {
for (int i = 0; i < d->extraData->eventFilters.count(); ++i) {
if (d->extraData->eventFilters.at(i) == obj)
d->extraData->eventFilters[i] = 0;
}
}
}
/*!
\fn void QObject::destroyed(QObject *obj)
This signal is emitted immediately before the object \a obj is
destroyed, and can not be blocked.
All the objects's children are destroyed immediately after this
signal is emitted.
\sa deleteLater(), QPointer
*/
/*!
\threadsafe
Schedules this object for deletion.
The object will be deleted when control returns to the event
loop. If the event loop is not running when this function is
called (e.g. deleteLater() is called on an object before
QCoreApplication::exec()), the object will be deleted once the
event loop is started. If deleteLater() is called after the main event loop
has stopped, the object will not be deleted.
Since Qt 4.8, if deleteLater() is called on an object that lives in a
thread with no running event loop, the object will be destroyed when the
thread finishes.
Note that entering and leaving a new event loop (e.g., by opening a modal
dialog) will \e not perform the deferred deletion; for the object to be
deleted, the control must return to the event loop from which deleteLater()
was called. This does not apply to objects deleted while a previous, nested
event loop was still running: the Qt event loop will delete those objects
as soon as the new nested event loop starts.
\b{Note:} It is safe to call this function more than once; when the
first deferred deletion event is delivered, any pending events for the
object are removed from the event queue.
\sa destroyed(), QPointer
*/
void QObject::deleteLater()
{
QCoreApplication::postEvent(this, new QDeferredDeleteEvent());
}
/*!
\fn QString QObject::tr(const char *sourceText, const char *disambiguation, int n)
\reentrant
Returns a translated version of \a sourceText, optionally based on a
\a disambiguation string and value of \a n for strings containing plurals;
otherwise returns QString::fromUtf8(\a sourceText) if no appropriate
translated string is available.
Example:
\snippet ../widgets/mainwindows/sdi/mainwindow.cpp implicit tr context
\dots
If the same \a sourceText is used in different roles within the
same context, an additional identifying string may be passed in
\a disambiguation (0 by default). In Qt 4.4 and earlier, this was
the preferred way to pass comments to translators.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 17
\dots
See \l{Writing Source Code for Translation} for a detailed description of
Qt's translation mechanisms in general, and the
\l{Writing Source Code for Translation#Disambiguation}{Disambiguation}
section for information on disambiguation.
\warning This method is reentrant only if all translators are
installed \e before calling this method. Installing or removing
translators while performing translations is not supported. Doing
so will probably result in crashes or other undesirable behavior.
\sa QCoreApplication::translate(), {Internationalization with Qt}
*/
/*!
\fn QString QObject::trUtf8(const char *sourceText, const char *disambiguation, int n)
\reentrant
\obsolete
Returns a translated version of \a sourceText, or
QString::fromUtf8(\a sourceText) if there is no appropriate
version. It is otherwise identical to tr(\a sourceText, \a
disambiguation, \a n).
\warning This method is reentrant only if all translators are
installed \e before calling this method. Installing or removing
translators while performing translations is not supported. Doing
so will probably result in crashes or other undesirable behavior.
\warning For portability reasons, we recommend that you use
escape sequences for specifying non-ASCII characters in string
literals to trUtf8(). For example:
\snippet code/src_corelib_kernel_qobject.cpp 20
\sa tr(), QCoreApplication::translate(), {Internationalization with Qt}
*/
/*****************************************************************************
Signals and slots
*****************************************************************************/
const char *qFlagLocation(const char *method)
{
QThreadData *currentThreadData = QThreadData::current(false);
if (currentThreadData != 0)
currentThreadData->flaggedSignatures.store(method);
return method;
}
static int extract_code(const char *member)
{
// extract code, ensure QMETHOD_CODE <= code <= QSIGNAL_CODE
return (((int)(*member) - '0') & 0x3);
}
static const char * extract_location(const char *member)
{
if (QThreadData::current()->flaggedSignatures.contains(member)) {
// signature includes location information after the first null-terminator
const char *location = member + qstrlen(member) + 1;
if (*location != '\0')
return location;
}
return 0;
}
static bool check_signal_macro(const QObject *sender, const char *signal,
const char *func, const char *op)
{
int sigcode = extract_code(signal);
if (sigcode != QSIGNAL_CODE) {
if (sigcode == QSLOT_CODE)
qWarning("QObject::%s: Attempt to %s non-signal %s::%s",
func, op, sender->metaObject()->className(), signal+1);
else
qWarning("QObject::%s: Use the SIGNAL macro to %s %s::%s",
func, op, sender->metaObject()->className(), signal);
return false;
}
return true;
}
static bool check_method_code(int code, const QObject *object,
const char *method, const char *func)
{
if (code != QSLOT_CODE && code != QSIGNAL_CODE) {
qWarning("QObject::%s: Use the SLOT or SIGNAL macro to "
"%s %s::%s", func, func, object->metaObject()->className(), method);
return false;
}
return true;
}
static void err_method_notfound(const QObject *object,
const char *method, const char *func)
{
const char *type = "method";
switch (extract_code(method)) {
case QSLOT_CODE: type = "slot"; break;
case QSIGNAL_CODE: type = "signal"; break;
}
const char *loc = extract_location(method);
if (strchr(method,')') == 0) // common typing mistake
qWarning("QObject::%s: Parentheses expected, %s %s::%s%s%s",
func, type, object->metaObject()->className(), method+1,
loc ? " in ": "", loc ? loc : "");
else
qWarning("QObject::%s: No such %s %s::%s%s%s",
func, type, object->metaObject()->className(), method+1,
loc ? " in ": "", loc ? loc : "");
}
static void err_info_about_objects(const char * func,
const QObject * sender,
const QObject * receiver)
{
QString a = sender ? sender->objectName() : QString();
QString b = receiver ? receiver->objectName() : QString();
if (!a.isEmpty())
qWarning("QObject::%s: (sender name: '%s')", func, a.toLocal8Bit().data());
if (!b.isEmpty())
qWarning("QObject::%s: (receiver name: '%s')", func, b.toLocal8Bit().data());
}
/*!
Returns a pointer to the object that sent the signal, if called in
a slot activated by a signal; otherwise it returns \nullptr. The pointer
is valid only during the execution of the slot that calls this
function from this object's thread context.
The pointer returned by this function becomes invalid if the
sender is destroyed, or if the slot is disconnected from the
sender's signal.
\warning This function violates the object-oriented principle of
modularity. However, getting access to the sender might be useful
when many signals are connected to a single slot.
\warning As mentioned above, the return value of this function is
not valid when the slot is called via a Qt::DirectConnection from
a thread different from this object's thread. Do not use this
function in this type of scenario.
\sa senderSignalIndex()
*/
QObject *QObject::sender() const
{
Q_D(const QObject);
QMutexLocker locker(signalSlotLock(this));
if (!d->currentSender)
return 0;
for (QObjectPrivate::Connection *c = d->senders; c; c = c->next) {
if (c->sender == d->currentSender->sender)
return d->currentSender->sender;
}
return 0;
}
/*!
\since 4.8
Returns the meta-method index of the signal that called the currently
executing slot, which is a member of the class returned by sender().
If called outside of a slot activated by a signal, -1 is returned.
For signals with default parameters, this function will always return
the index with all parameters, regardless of which was used with
connect(). For example, the signal \c {destroyed(QObject *obj = 0)}
will have two different indexes (with and without the parameter), but
this function will always return the index with a parameter. This does
not apply when overloading signals with different parameters.
\warning This function violates the object-oriented principle of
modularity. However, getting access to the signal index might be useful
when many signals are connected to a single slot.
\warning The return value of this function is not valid when the slot
is called via a Qt::DirectConnection from a thread different from this
object's thread. Do not use this function in this type of scenario.
\sa sender(), QMetaObject::indexOfSignal(), QMetaObject::method()
*/
int QObject::senderSignalIndex() const
{
Q_D(const QObject);
QMutexLocker locker(signalSlotLock(this));
if (!d->currentSender)
return -1;
for (QObjectPrivate::Connection *c = d->senders; c; c = c->next) {
if (c->sender == d->currentSender->sender) {
// Convert from signal range to method range
return QMetaObjectPrivate::signal(c->sender->metaObject(), d->currentSender->signal).methodIndex();
}
}
return -1;
}
/*!
Returns the number of receivers connected to the \a signal.
Since both slots and signals can be used as receivers for signals,
and the same connections can be made many times, the number of
receivers is the same as the number of connections made from this
signal.
When calling this function, you can use the \c SIGNAL() macro to
pass a specific signal:
\snippet code/src_corelib_kernel_qobject.cpp 21
\warning This function violates the object-oriented principle of
modularity. However, it might be useful when you need to perform
expensive initialization only if something is connected to a
signal.
\sa isSignalConnected()
*/
int QObject::receivers(const char *signal) const
{
Q_D(const QObject);
int receivers = 0;
if (signal) {
QByteArray signal_name = QMetaObject::normalizedSignature(signal);
signal = signal_name;
#ifndef QT_NO_DEBUG
if (!check_signal_macro(this, signal, "receivers", "bind"))
return 0;
#endif
signal++; // skip code
int signal_index = d->signalIndex(signal);
if (signal_index < 0) {
#ifndef QT_NO_DEBUG
err_method_notfound(this, signal-1, "receivers");
#endif
return 0;
}
if (!d->isSignalConnected(signal_index))
return receivers;
if (d->declarativeData && QAbstractDeclarativeData::receivers) {
receivers += QAbstractDeclarativeData::receivers(d->declarativeData, this,
signal_index);
}
QMutexLocker locker(signalSlotLock(this));
if (d->connectionLists) {
if (signal_index < d->connectionLists->count()) {
const QObjectPrivate::Connection *c =
d->connectionLists->at(signal_index).first;
while (c) {
receivers += c->receiver ? 1 : 0;
c = c->nextConnectionList;
}
}
}
}
return receivers;
}
/*!
\since 5.0
Returns \c true if the \a signal is connected to at least one receiver,
otherwise returns \c false.
\a signal must be a signal member of this object, otherwise the behaviour
is undefined.
\snippet code/src_corelib_kernel_qobject.cpp 49
As the code snippet above illustrates, you can use this function
to avoid emitting a signal that nobody listens to.
\warning This function violates the object-oriented principle of
modularity. However, it might be useful when you need to perform
expensive initialization only if something is connected to a
signal.
*/
bool QObject::isSignalConnected(const QMetaMethod &signal) const
{
Q_D(const QObject);
if (!signal.mobj)
return false;
Q_ASSERT_X(signal.mobj->cast(this) && signal.methodType() == QMetaMethod::Signal,
"QObject::isSignalConnected" , "the parameter must be a signal member of the object");
uint signalIndex = (signal.handle - QMetaObjectPrivate::get(signal.mobj)->methodData)/5;
if (signal.mobj->d.data[signal.handle + 4] & MethodCloned)
signalIndex = QMetaObjectPrivate::originalClone(signal.mobj, signalIndex);
signalIndex += QMetaObjectPrivate::signalOffset(signal.mobj);
QMutexLocker locker(signalSlotLock(this));
if (d->connectionLists) {
if (signalIndex < sizeof(d->connectedSignals) * 8 && !d->connectionLists->dirty)
return d->isSignalConnected(signalIndex);
if (signalIndex < uint(d->connectionLists->count())) {
const QObjectPrivate::Connection *c =
d->connectionLists->at(signalIndex).first;
while (c) {
if (c->receiver)
return true;
c = c->nextConnectionList;
}
}
}
return d->isDeclarativeSignalConnected(signalIndex);
}
/*!
\internal
This helper function calculates signal and method index for the given
member in the specified class.
\list
\li If member.mobj is 0 then both signalIndex and methodIndex are set to -1.
\li If specified member is not a member of obj instance class (or one of
its parent classes) then both signalIndex and methodIndex are set to -1.
\endlist
This function is used by QObject::connect and QObject::disconnect which
are working with QMetaMethod.
\a signalIndex is set to the signal index of member. If the member
specified is not signal this variable is set to -1.
\a methodIndex is set to the method index of the member. If the
member is not a method of the object specified by the \a obj argument this
variable is set to -1.
*/
void QMetaObjectPrivate::memberIndexes(const QObject *obj,
const QMetaMethod &member,
int *signalIndex, int *methodIndex)
{
*signalIndex = -1;
*methodIndex = -1;
if (!obj || !member.mobj)
return;
const QMetaObject *m = obj->metaObject();
// Check that member is member of obj class
while (m != 0 && m != member.mobj)
m = m->d.superdata;
if (!m)
return;
*signalIndex = *methodIndex = (member.handle - get(member.mobj)->methodData)/5;
int signalOffset;
int methodOffset;
computeOffsets(m, &signalOffset, &methodOffset);
*methodIndex += methodOffset;
if (member.methodType() == QMetaMethod::Signal) {
*signalIndex = originalClone(m, *signalIndex);
*signalIndex += signalOffset;
} else {
*signalIndex = -1;
}
}
#ifndef QT_NO_DEBUG
static inline void check_and_warn_compat(const QMetaObject *sender, const QMetaMethod &signal,
const QMetaObject *receiver, const QMetaMethod &method)
{
if (signal.attributes() & QMetaMethod::Compatibility) {
if (!(method.attributes() & QMetaMethod::Compatibility))
qWarning("QObject::connect: Connecting from COMPAT signal (%s::%s)",
sender->className(), signal.methodSignature().constData());
} else if ((method.attributes() & QMetaMethod::Compatibility) &&
method.methodType() == QMetaMethod::Signal) {
qWarning("QObject::connect: Connecting from %s::%s to COMPAT slot (%s::%s)",
sender->className(), signal.methodSignature().constData(),
receiver->className(), method.methodSignature().constData());
}
}
#endif
/*!
\threadsafe
Creates a connection of the given \a type from the \a signal in
the \a sender object to the \a method in the \a receiver object.
Returns a handle to the connection that can be used to disconnect
it later.
You must use the \c SIGNAL() and \c SLOT() macros when specifying
the \a signal and the \a method, for example:
\snippet code/src_corelib_kernel_qobject.cpp 22
This example ensures that the label always displays the current
scroll bar value. Note that the signal and slots parameters must not
contain any variable names, only the type. E.g. the following would
not work and return false:
\snippet code/src_corelib_kernel_qobject.cpp 23
A signal can also be connected to another signal:
\snippet code/src_corelib_kernel_qobject.cpp 24
In this example, the \c MyWidget constructor relays a signal from
a private member variable, and makes it available under a name
that relates to \c MyWidget.
A signal can be connected to many slots and signals. Many signals
can be connected to one slot.
If a signal is connected to several slots, the slots are activated
in the same order in which the connections were made, when the
signal is emitted.
The function returns a QMetaObject::Connection that represents
a handle to a connection if it successfully
connects the signal to the slot. The connection handle will be invalid
if it cannot create the connection, for example, if QObject is unable
to verify the existence of either \a signal or \a method, or if their
signatures aren't compatible.
You can check if the handle is valid by casting it to a bool.
By default, a signal is emitted for every connection you make;
two signals are emitted for duplicate connections. You can break
all of these connections with a single disconnect() call.
If you pass the Qt::UniqueConnection \a type, the connection will only
be made if it is not a duplicate. If there is already a duplicate
(exact same signal to the exact same slot on the same objects),
the connection will fail and connect will return an invalid QMetaObject::Connection.
\note Qt::UniqueConnections do not work for lambdas, non-member functions
and functors; they only apply to connecting to member functions.
The optional \a type parameter describes the type of connection
to establish. In particular, it determines whether a particular
signal is delivered to a slot immediately or queued for delivery
at a later time. If the signal is queued, the parameters must be
of types that are known to Qt's meta-object system, because Qt
needs to copy the arguments to store them in an event behind the
scenes. If you try to use a queued connection and get the error
message
\snippet code/src_corelib_kernel_qobject.cpp 25
call qRegisterMetaType() to register the data type before you
establish the connection.
\sa disconnect(), sender(), qRegisterMetaType(), Q_DECLARE_METATYPE(),
{Differences between String-Based and Functor-Based Connections}
*/
QMetaObject::Connection QObject::connect(const QObject *sender, const char *signal,
const QObject *receiver, const char *method,
Qt::ConnectionType type)
{
if (sender == 0 || receiver == 0 || signal == 0 || method == 0) {
qWarning("QObject::connect: Cannot connect %s::%s to %s::%s",
sender ? sender->metaObject()->className() : "(null)",
(signal && *signal) ? signal+1 : "(null)",
receiver ? receiver->metaObject()->className() : "(null)",
(method && *method) ? method+1 : "(null)");
return QMetaObject::Connection(0);
}
QByteArray tmp_signal_name;
if (!check_signal_macro(sender, signal, "connect", "bind"))
return QMetaObject::Connection(0);
const QMetaObject *smeta = sender->metaObject();
const char *signal_arg = signal;
++signal; //skip code
QArgumentTypeArray signalTypes;
Q_ASSERT(QMetaObjectPrivate::get(smeta)->revision >= 7);
QByteArray signalName = QMetaObjectPrivate::decodeMethodSignature(signal, signalTypes);
int signal_index = QMetaObjectPrivate::indexOfSignalRelative(
&smeta, signalName, signalTypes.size(), signalTypes.constData());
if (signal_index < 0) {
// check for normalized signatures
tmp_signal_name = QMetaObject::normalizedSignature(signal - 1);
signal = tmp_signal_name.constData() + 1;
signalTypes.clear();
signalName = QMetaObjectPrivate::decodeMethodSignature(signal, signalTypes);
smeta = sender->metaObject();
signal_index = QMetaObjectPrivate::indexOfSignalRelative(
&smeta, signalName, signalTypes.size(), signalTypes.constData());
}
if (signal_index < 0) {
err_method_notfound(sender, signal_arg, "connect");
err_info_about_objects("connect", sender, receiver);
return QMetaObject::Connection(0);
}
signal_index = QMetaObjectPrivate::originalClone(smeta, signal_index);
signal_index += QMetaObjectPrivate::signalOffset(smeta);
QByteArray tmp_method_name;
int membcode = extract_code(method);
if (!check_method_code(membcode, receiver, method, "connect"))
return QMetaObject::Connection(0);
const char *method_arg = method;
++method; // skip code
QArgumentTypeArray methodTypes;
QByteArray methodName = QMetaObjectPrivate::decodeMethodSignature(method, methodTypes);
const QMetaObject *rmeta = receiver->metaObject();
int method_index_relative = -1;
Q_ASSERT(QMetaObjectPrivate::get(rmeta)->revision >= 7);
switch (membcode) {
case QSLOT_CODE:
method_index_relative = QMetaObjectPrivate::indexOfSlotRelative(
&rmeta, methodName, methodTypes.size(), methodTypes.constData());
break;
case QSIGNAL_CODE:
method_index_relative = QMetaObjectPrivate::indexOfSignalRelative(
&rmeta, methodName, methodTypes.size(), methodTypes.constData());
break;
}
if (method_index_relative < 0) {
// check for normalized methods
tmp_method_name = QMetaObject::normalizedSignature(method);
method = tmp_method_name.constData();
methodTypes.clear();
methodName = QMetaObjectPrivate::decodeMethodSignature(method, methodTypes);
// rmeta may have been modified above
rmeta = receiver->metaObject();
switch (membcode) {
case QSLOT_CODE:
method_index_relative = QMetaObjectPrivate::indexOfSlotRelative(
&rmeta, methodName, methodTypes.size(), methodTypes.constData());
break;
case QSIGNAL_CODE:
method_index_relative = QMetaObjectPrivate::indexOfSignalRelative(
&rmeta, methodName, methodTypes.size(), methodTypes.constData());
break;
}
}
if (method_index_relative < 0) {
err_method_notfound(receiver, method_arg, "connect");
err_info_about_objects("connect", sender, receiver);
return QMetaObject::Connection(0);
}
if (!QMetaObjectPrivate::checkConnectArgs(signalTypes.size(), signalTypes.constData(),
methodTypes.size(), methodTypes.constData())) {
qWarning("QObject::connect: Incompatible sender/receiver arguments"
"\n %s::%s --> %s::%s",
sender->metaObject()->className(), signal,
receiver->metaObject()->className(), method);
return QMetaObject::Connection(0);
}
int *types = 0;
if ((type == Qt::QueuedConnection)
&& !(types = queuedConnectionTypes(signalTypes.constData(), signalTypes.size()))) {
return QMetaObject::Connection(0);
}
#ifndef QT_NO_DEBUG
QMetaMethod smethod = QMetaObjectPrivate::signal(smeta, signal_index);
QMetaMethod rmethod = rmeta->method(method_index_relative + rmeta->methodOffset());
check_and_warn_compat(smeta, smethod, rmeta, rmethod);
#endif
QMetaObject::Connection handle = QMetaObject::Connection(QMetaObjectPrivate::connect(
sender, signal_index, smeta, receiver, method_index_relative, rmeta ,type, types));
return handle;
}
/*!
\since 4.8
Creates a connection of the given \a type from the \a signal in
the \a sender object to the \a method in the \a receiver object.
Returns a handle to the connection that can be used to disconnect
it later.
The Connection handle will be invalid if it cannot create the
connection, for example, the parameters were invalid.
You can check if the QMetaObject::Connection is valid by casting it to a bool.
This function works in the same way as
\c {connect(const QObject *sender, const char *signal,
const QObject *receiver, const char *method,
Qt::ConnectionType type)}
but it uses QMetaMethod to specify signal and method.
\sa connect(const QObject *sender, const char *signal, const QObject *receiver, const char *method, Qt::ConnectionType type)
*/
QMetaObject::Connection QObject::connect(const QObject *sender, const QMetaMethod &signal,
const QObject *receiver, const QMetaMethod &method,
Qt::ConnectionType type)
{
if (sender == 0
|| receiver == 0
|| signal.methodType() != QMetaMethod::Signal
|| method.methodType() == QMetaMethod::Constructor) {
qWarning("QObject::connect: Cannot connect %s::%s to %s::%s",
sender ? sender->metaObject()->className() : "(null)",
signal.methodSignature().constData(),
receiver ? receiver->metaObject()->className() : "(null)",
method.methodSignature().constData() );
return QMetaObject::Connection(0);
}
int signal_index;
int method_index;
{
int dummy;
QMetaObjectPrivate::memberIndexes(sender, signal, &signal_index, &dummy);
QMetaObjectPrivate::memberIndexes(receiver, method, &dummy, &method_index);
}
const QMetaObject *smeta = sender->metaObject();
const QMetaObject *rmeta = receiver->metaObject();
if (signal_index == -1) {
qWarning("QObject::connect: Can't find signal %s on instance of class %s",
signal.methodSignature().constData(), smeta->className());
return QMetaObject::Connection(0);
}
if (method_index == -1) {
qWarning("QObject::connect: Can't find method %s on instance of class %s",
method.methodSignature().constData(), rmeta->className());
return QMetaObject::Connection(0);
}
if (!QMetaObject::checkConnectArgs(signal.methodSignature().constData(), method.methodSignature().constData())) {
qWarning("QObject::connect: Incompatible sender/receiver arguments"
"\n %s::%s --> %s::%s",
smeta->className(), signal.methodSignature().constData(),
rmeta->className(), method.methodSignature().constData());
return QMetaObject::Connection(0);
}
int *types = 0;
if ((type == Qt::QueuedConnection)
&& !(types = queuedConnectionTypes(signal.parameterTypes())))
return QMetaObject::Connection(0);
#ifndef QT_NO_DEBUG
check_and_warn_compat(smeta, signal, rmeta, method);
#endif
QMetaObject::Connection handle = QMetaObject::Connection(QMetaObjectPrivate::connect(
sender, signal_index, signal.enclosingMetaObject(), receiver, method_index, 0, type, types));
return handle;
}
/*!
\fn bool QObject::connect(const QObject *sender, const char *signal, const char *method, Qt::ConnectionType type) const
\overload connect()
\threadsafe
Connects \a signal from the \a sender object to this object's \a
method.
Equivalent to connect(\a sender, \a signal, \c this, \a method, \a type).
Every connection you make emits a signal, so duplicate connections emit
two signals. You can break a connection using disconnect().
\sa disconnect()
*/
/*!
\threadsafe
Disconnects \a signal in object \a sender from \a method in object
\a receiver. Returns \c true if the connection is successfully broken;
otherwise returns \c false.
A signal-slot connection is removed when either of the objects
involved are destroyed.
disconnect() is typically used in three ways, as the following
examples demonstrate.
\list 1
\li Disconnect everything connected to an object's signals:
\snippet code/src_corelib_kernel_qobject.cpp 26
equivalent to the non-static overloaded function
\snippet code/src_corelib_kernel_qobject.cpp 27
\li Disconnect everything connected to a specific signal:
\snippet code/src_corelib_kernel_qobject.cpp 28
equivalent to the non-static overloaded function
\snippet code/src_corelib_kernel_qobject.cpp 29
\li Disconnect a specific receiver:
\snippet code/src_corelib_kernel_qobject.cpp 30
equivalent to the non-static overloaded function
\snippet code/src_corelib_kernel_qobject.cpp 31
\endlist
0 may be used as a wildcard, meaning "any signal", "any receiving
object", or "any slot in the receiving object", respectively.
The \a sender may never be 0. (You cannot disconnect signals from
more than one object in a single call.)
If \a signal is 0, it disconnects \a receiver and \a method from
any signal. If not, only the specified signal is disconnected.
If \a receiver is 0, it disconnects anything connected to \a
signal. If not, slots in objects other than \a receiver are not
disconnected.
If \a method is 0, it disconnects anything that is connected to \a
receiver. If not, only slots named \a method will be disconnected,
and all other slots are left alone. The \a method must be 0 if \a
receiver is left out, so you cannot disconnect a
specifically-named slot on all objects.
\sa connect()
*/
bool QObject::disconnect(const QObject *sender, const char *signal,
const QObject *receiver, const char *method)
{
if (sender == 0 || (receiver == 0 && method != 0)) {
qWarning("QObject::disconnect: Unexpected null parameter");
return false;
}
const char *signal_arg = signal;
QByteArray signal_name;
bool signal_found = false;
if (signal) {
QT_TRY {
signal_name = QMetaObject::normalizedSignature(signal);
signal = signal_name.constData();
} QT_CATCH (const std::bad_alloc &) {
// if the signal is already normalized, we can continue.
if (sender->metaObject()->indexOfSignal(signal + 1) == -1)
QT_RETHROW;
}
if (!check_signal_macro(sender, signal, "disconnect", "unbind"))
return false;
signal++; // skip code
}
QByteArray method_name;
const char *method_arg = method;
int membcode = -1;
bool method_found = false;
if (method) {
QT_TRY {
method_name = QMetaObject::normalizedSignature(method);
method = method_name.constData();
} QT_CATCH(const std::bad_alloc &) {
// if the method is already normalized, we can continue.
if (receiver->metaObject()->indexOfMethod(method + 1) == -1)
QT_RETHROW;
}
membcode = extract_code(method);
if (!check_method_code(membcode, receiver, method, "disconnect"))
return false;
method++; // skip code
}
/* We now iterate through all the sender's and receiver's meta
* objects in order to also disconnect possibly shadowed signals
* and slots with the same signature.
*/
bool res = false;
const QMetaObject *smeta = sender->metaObject();
QByteArray signalName;
QArgumentTypeArray signalTypes;
Q_ASSERT(QMetaObjectPrivate::get(smeta)->revision >= 7);
if (signal)
signalName = QMetaObjectPrivate::decodeMethodSignature(signal, signalTypes);
QByteArray methodName;
QArgumentTypeArray methodTypes;
Q_ASSERT(!receiver || QMetaObjectPrivate::get(receiver->metaObject())->revision >= 7);
if (method)
methodName = QMetaObjectPrivate::decodeMethodSignature(method, methodTypes);
do {
int signal_index = -1;
if (signal) {
signal_index = QMetaObjectPrivate::indexOfSignalRelative(
&smeta, signalName, signalTypes.size(), signalTypes.constData());
if (signal_index < 0)
break;
signal_index = QMetaObjectPrivate::originalClone(smeta, signal_index);
signal_index += QMetaObjectPrivate::signalOffset(smeta);
signal_found = true;
}
if (!method) {
res |= QMetaObjectPrivate::disconnect(sender, signal_index, smeta, receiver, -1, 0);
} else {
const QMetaObject *rmeta = receiver->metaObject();
do {
int method_index = QMetaObjectPrivate::indexOfMethod(
rmeta, methodName, methodTypes.size(), methodTypes.constData());
if (method_index >= 0)
while (method_index < rmeta->methodOffset())
rmeta = rmeta->superClass();
if (method_index < 0)
break;
res |= QMetaObjectPrivate::disconnect(sender, signal_index, smeta, receiver, method_index, 0);
method_found = true;
} while ((rmeta = rmeta->superClass()));
}
} while (signal && (smeta = smeta->superClass()));
if (signal && !signal_found) {
err_method_notfound(sender, signal_arg, "disconnect");
err_info_about_objects("disconnect", sender, receiver);
} else if (method && !method_found) {
err_method_notfound(receiver, method_arg, "disconnect");
err_info_about_objects("disconnect", sender, receiver);
}
if (res) {
if (!signal)
const_cast<QObject*>(sender)->disconnectNotify(QMetaMethod());
}
return res;
}
/*!
\since 4.8
Disconnects \a signal in object \a sender from \a method in object
\a receiver. Returns \c true if the connection is successfully broken;
otherwise returns \c false.
This function provides the same possibilities like
\c {disconnect(const QObject *sender, const char *signal, const QObject *receiver, const char *method) }
but uses QMetaMethod to represent the signal and the method to be disconnected.
Additionally this function returnsfalse and no signals and slots disconnected
if:
\list 1
\li \a signal is not a member of sender class or one of its parent classes.
\li \a method is not a member of receiver class or one of its parent classes.
\li \a signal instance represents not a signal.
\endlist
QMetaMethod() may be used as wildcard in the meaning "any signal" or "any slot in receiving object".
In the same way 0 can be used for \a receiver in the meaning "any receiving object". In this case
method should also be QMetaMethod(). \a sender parameter should be never 0.
\sa disconnect(const QObject *sender, const char *signal, const QObject *receiver, const char *method)
*/
bool QObject::disconnect(const QObject *sender, const QMetaMethod &signal,
const QObject *receiver, const QMetaMethod &method)
{
if (sender == 0 || (receiver == 0 && method.mobj != 0)) {
qWarning("QObject::disconnect: Unexpected null parameter");
return false;
}
if (signal.mobj) {
if(signal.methodType() != QMetaMethod::Signal) {
qWarning("QObject::%s: Attempt to %s non-signal %s::%s",
"disconnect","unbind",
sender->metaObject()->className(), signal.methodSignature().constData());
return false;
}
}
if (method.mobj) {
if(method.methodType() == QMetaMethod::Constructor) {
qWarning("QObject::disconect: cannot use constructor as argument %s::%s",
receiver->metaObject()->className(), method.methodSignature().constData());
return false;
}
}
// Reconstructing SIGNAL() macro result for signal.methodSignature() string
QByteArray signalSignature;
if (signal.mobj) {
signalSignature.reserve(signal.methodSignature().size()+1);
signalSignature.append((char)(QSIGNAL_CODE + '0'));
signalSignature.append(signal.methodSignature());
}
int signal_index;
int method_index;
{
int dummy;
QMetaObjectPrivate::memberIndexes(sender, signal, &signal_index, &dummy);
QMetaObjectPrivate::memberIndexes(receiver, method, &dummy, &method_index);
}
// If we are here sender is not null. If signal is not null while signal_index
// is -1 then this signal is not a member of sender.
if (signal.mobj && signal_index == -1) {
qWarning("QObject::disconect: signal %s not found on class %s",
signal.methodSignature().constData(), sender->metaObject()->className());
return false;
}
// If this condition is true then method is not a member of receeiver.
if (receiver && method.mobj && method_index == -1) {
qWarning("QObject::disconect: method %s not found on class %s",
method.methodSignature().constData(), receiver->metaObject()->className());
return false;
}
if (!QMetaObjectPrivate::disconnect(sender, signal_index, signal.mobj, receiver, method_index, 0))
return false;
if (!signal.isValid()) {
// The signal is a wildcard, meaning all signals were disconnected.
// QMetaObjectPrivate::disconnect() doesn't call disconnectNotify()
// per connection in this case. Call it once now, with an invalid
// QMetaMethod as argument, as documented.
const_cast<QObject*>(sender)->disconnectNotify(signal);
}
return true;
}
/*!
\threadsafe
\fn bool QObject::disconnect(const char *signal, const QObject *receiver, const char *method) const
\overload disconnect()
Disconnects \a signal from \a method of \a receiver.
A signal-slot connection is removed when either of the objects
involved are destroyed.
*/
/*!
\fn bool QObject::disconnect(const QObject *receiver, const char *method) const
\overload disconnect()
Disconnects all signals in this object from \a receiver's \a
method.
A signal-slot connection is removed when either of the objects
involved are destroyed.
*/
/*!
\since 5.0
This virtual function is called when something has been connected
to \a signal in this object.
If you want to compare \a signal with a specific signal, you can
use QMetaMethod::fromSignal() as follows:
\snippet code/src_corelib_kernel_qobject.cpp 32
\warning This function violates the object-oriented principle of
modularity. However, it might be useful when you need to perform
expensive initialization only if something is connected to a
signal.
\warning This function is called from the thread which performs the
connection, which may be a different thread from the thread in
which this object lives.
\sa connect(), disconnectNotify()
*/
void QObject::connectNotify(const QMetaMethod &signal)
{
Q_UNUSED(signal);
}
/*!
\since 5.0
This virtual function is called when something has been
disconnected from \a signal in this object.
See connectNotify() for an example of how to compare
\a signal with a specific signal.
If all signals were disconnected from this object (e.g., the
signal argument to disconnect() was 0), disconnectNotify()
is only called once, and the \a signal will be an invalid
QMetaMethod (QMetaMethod::isValid() returns \c false).
\warning This function violates the object-oriented principle of
modularity. However, it might be useful for optimizing access to
expensive resources.
\warning This function is called from the thread which performs the
disconnection, which may be a different thread from the thread in
which this object lives. This function may also be called with a QObject
internal mutex locked. It is therefore not allowed to re-enter any
of any QObject functions from your reimplementation and if you lock
a mutex in your reimplementation, make sure that you don't call QObject
functions with that mutex held in other places or it will result in
a deadlock.
\sa disconnect(), connectNotify()
*/
void QObject::disconnectNotify(const QMetaMethod &signal)
{
Q_UNUSED(signal);
}
/*
\internal
convert a signal index from the method range to the signal range
*/
static int methodIndexToSignalIndex(const QMetaObject **base, int signal_index)
{
if (signal_index < 0)
return signal_index;
const QMetaObject *metaObject = *base;
while (metaObject && metaObject->methodOffset() > signal_index)
metaObject = metaObject->superClass();
if (metaObject) {
int signalOffset, methodOffset;
computeOffsets(metaObject, &signalOffset, &methodOffset);
if (signal_index < metaObject->methodCount())
signal_index = QMetaObjectPrivate::originalClone(metaObject, signal_index - methodOffset) + signalOffset;
else
signal_index = signal_index - methodOffset + signalOffset;
*base = metaObject;
}
return signal_index;
}
/*!
\internal
\a types is a 0-terminated vector of meta types for queued
connections.
if \a signal_index is -1, then we effectively connect *all* signals
from the sender to the receiver's slot
*/
QMetaObject::Connection QMetaObject::connect(const QObject *sender, int signal_index,
const QObject *receiver, int method_index, int type, int *types)
{
const QMetaObject *smeta = sender->metaObject();
signal_index = methodIndexToSignalIndex(&smeta, signal_index);
return Connection(QMetaObjectPrivate::connect(sender, signal_index, smeta,
receiver, method_index,
0, //FIXME, we could speed this connection up by computing the relative index
type, types));
}
/*!
\internal
Same as the QMetaObject::connect, but \a signal_index must be the result of QObjectPrivate::signalIndex
method_index is relative to the rmeta metaobject, if rmeta is null, then it is absolute index
the QObjectPrivate::Connection* has a refcount of 2, so it must be passed to a QMetaObject::Connection
*/
QObjectPrivate::Connection *QMetaObjectPrivate::connect(const QObject *sender,
int signal_index, const QMetaObject *smeta,
const QObject *receiver, int method_index,
const QMetaObject *rmeta, int type, int *types)
{
QObject *s = const_cast<QObject *>(sender);
QObject *r = const_cast<QObject *>(receiver);
int method_offset = rmeta ? rmeta->methodOffset() : 0;
Q_ASSERT(!rmeta || QMetaObjectPrivate::get(rmeta)->revision >= 6);
QObjectPrivate::StaticMetaCallFunction callFunction =
rmeta ? rmeta->d.static_metacall : 0;
QOrderedMutexLocker locker(signalSlotLock(sender),
signalSlotLock(receiver));
if (type & Qt::UniqueConnection) {
QObjectConnectionListVector *connectionLists = QObjectPrivate::get(s)->connectionLists;
if (connectionLists && connectionLists->count() > signal_index) {
const QObjectPrivate::Connection *c2 =
(*connectionLists)[signal_index].first;
int method_index_absolute = method_index + method_offset;
while (c2) {
if (!c2->isSlotObject && c2->receiver == receiver && c2->method() == method_index_absolute)
return 0;
c2 = c2->nextConnectionList;
}
}
type &= Qt::UniqueConnection - 1;
}
QScopedPointer<QObjectPrivate::Connection> c(new QObjectPrivate::Connection);
c->sender = s;
c->signal_index = signal_index;
c->receiver = r;
c->method_relative = method_index;
c->method_offset = method_offset;
c->connectionType = type;
c->isSlotObject = false;
c->argumentTypes.store(types);
c->nextConnectionList = 0;
c->callFunction = callFunction;
QObjectPrivate::get(s)->addConnection(signal_index, c.data());
locker.unlock();
QMetaMethod smethod = QMetaObjectPrivate::signal(smeta, signal_index);
if (smethod.isValid())
s->connectNotify(smethod);
return c.take();
}
/*!
\internal
*/
bool QMetaObject::disconnect(const QObject *sender, int signal_index,
const QObject *receiver, int method_index)
{
const QMetaObject *smeta = sender->metaObject();
signal_index = methodIndexToSignalIndex(&smeta, signal_index);
return QMetaObjectPrivate::disconnect(sender, signal_index, smeta,
receiver, method_index, 0);
}
/*!
\internal
Disconnect a single signal connection. If QMetaObject::connect() has been called
multiple times for the same sender, signal_index, receiver and method_index only
one of these connections will be removed.
*/
bool QMetaObject::disconnectOne(const QObject *sender, int signal_index,
const QObject *receiver, int method_index)
{
const QMetaObject *smeta = sender->metaObject();
signal_index = methodIndexToSignalIndex(&smeta, signal_index);
return QMetaObjectPrivate::disconnect(sender, signal_index, smeta,
receiver, method_index, 0,
QMetaObjectPrivate::DisconnectOne);
}
/*!
\internal
Helper function to remove the connection from the senders list and setting the receivers to 0
*/
bool QMetaObjectPrivate::disconnectHelper(QObjectPrivate::Connection *c,
const QObject *receiver, int method_index, void **slot,
QMutex *senderMutex, DisconnectType disconnectType)
{
bool success = false;
while (c) {
if (c->receiver
&& (receiver == 0 || (c->receiver == receiver
&& (method_index < 0 || (!c->isSlotObject && c->method() == method_index))
&& (slot == 0 || (c->isSlotObject && c->slotObj->compare(slot)))))) {
bool needToUnlock = false;
QMutex *receiverMutex = 0;
if (c->receiver) {
receiverMutex = signalSlotLock(c->receiver);
// need to relock this receiver and sender in the correct order
needToUnlock = QOrderedMutexLocker::relock(senderMutex, receiverMutex);
}
if (c->receiver) {
*c->prev = c->next;
if (c->next)
c->next->prev = c->prev;
}
if (needToUnlock)
receiverMutex->unlock();
c->receiver = 0;
if (c->isSlotObject) {
c->isSlotObject = false;
senderMutex->unlock();
c->slotObj->destroyIfLastRef();
senderMutex->lock();
}
success = true;
if (disconnectType == DisconnectOne)
return success;
}
c = c->nextConnectionList;
}
return success;
}
/*!
\internal
Same as the QMetaObject::disconnect, but \a signal_index must be the result of QObjectPrivate::signalIndex
*/
bool QMetaObjectPrivate::disconnect(const QObject *sender,
int signal_index, const QMetaObject *smeta,
const QObject *receiver, int method_index, void **slot,
DisconnectType disconnectType)
{
if (!sender)
return false;
QObject *s = const_cast<QObject *>(sender);
QMutex *senderMutex = signalSlotLock(sender);
QMutexLocker locker(senderMutex);
QObjectConnectionListVector *connectionLists = QObjectPrivate::get(s)->connectionLists;
if (!connectionLists)
return false;
// prevent incoming connections changing the connectionLists while unlocked
++connectionLists->inUse;
bool success = false;
if (signal_index < 0) {
// remove from all connection lists
for (int sig_index = -1; sig_index < connectionLists->count(); ++sig_index) {
QObjectPrivate::Connection *c =
(*connectionLists)[sig_index].first;
if (disconnectHelper(c, receiver, method_index, slot, senderMutex, disconnectType)) {
success = true;
connectionLists->dirty = true;
}
}
} else if (signal_index < connectionLists->count()) {
QObjectPrivate::Connection *c =
(*connectionLists)[signal_index].first;
if (disconnectHelper(c, receiver, method_index, slot, senderMutex, disconnectType)) {
success = true;
connectionLists->dirty = true;
}
}
--connectionLists->inUse;
Q_ASSERT(connectionLists->inUse >= 0);
if (connectionLists->orphaned && !connectionLists->inUse)
delete connectionLists;
locker.unlock();
if (success) {
QMetaMethod smethod = QMetaObjectPrivate::signal(smeta, signal_index);
if (smethod.isValid())
s->disconnectNotify(smethod);
}
return success;
}
/*!
\fn void QMetaObject::connectSlotsByName(QObject *object)
Searches recursively for all child objects of the given \a object, and connects
matching signals from them to slots of \a object that follow the following form:
\snippet code/src_corelib_kernel_qobject.cpp 33
Let's assume our object has a child object of type \c{QPushButton} with
the \l{QObject::objectName}{object name} \c{button1}. The slot to catch the
button's \c{clicked()} signal would be:
\snippet code/src_corelib_kernel_qobject.cpp 34
If \a object itself has a properly set object name, its own signals are also
connected to its respective slots.
\sa QObject::setObjectName()
*/
void QMetaObject::connectSlotsByName(QObject *o)
{
if (!o)
return;
const QMetaObject *mo = o->metaObject();
Q_ASSERT(mo);
const QObjectList list = // list of all objects to look for matching signals including...
o->findChildren<QObject *>(QString()) // all children of 'o'...
<< o; // and the object 'o' itself
// for each method/slot of o ...
for (int i = 0; i < mo->methodCount(); ++i) {
const QByteArray slotSignature = mo->method(i).methodSignature();
const char *slot = slotSignature.constData();
Q_ASSERT(slot);
// ...that starts with "on_", ...
if (slot[0] != 'o' || slot[1] != 'n' || slot[2] != '_')
continue;
// ...we check each object in our list, ...
bool foundIt = false;
for(int j = 0; j < list.count(); ++j) {
const QObject *co = list.at(j);
const QByteArray coName = co->objectName().toLatin1();
// ...discarding those whose objectName is not fitting the pattern "on_<objectName>_...", ...
if (coName.isEmpty() || qstrncmp(slot + 3, coName.constData(), coName.size()) || slot[coName.size()+3] != '_')
continue;
const char *signal = slot + coName.size() + 4; // the 'signal' part of the slot name
// ...for the presence of a matching signal "on_<objectName>_<signal>".
const QMetaObject *smeta;
int sigIndex = co->d_func()->signalIndex(signal, &smeta);
if (sigIndex < 0) {
// if no exactly fitting signal (name + complete parameter type list) could be found
// look for just any signal with the correct name and at least the slot's parameter list.
// Note: if more than one of thoses signals exist, the one that gets connected is
// chosen 'at random' (order of declaration in source file)
QList<QByteArray> compatibleSignals;
const QMetaObject *smo = co->metaObject();
int sigLen = qstrlen(signal) - 1; // ignore the trailing ')'
for (int k = QMetaObjectPrivate::absoluteSignalCount(smo)-1; k >= 0; --k) {
const QMetaMethod method = QMetaObjectPrivate::signal(smo, k);
if (!qstrncmp(method.methodSignature().constData(), signal, sigLen)) {
smeta = method.enclosingMetaObject();
sigIndex = k;
compatibleSignals.prepend(method.methodSignature());
}
}
if (compatibleSignals.size() > 1)
qWarning() << "QMetaObject::connectSlotsByName: Connecting slot" << slot
<< "with the first of the following compatible signals:" << compatibleSignals;
}
if (sigIndex < 0)
continue;
// we connect it...
if (Connection(QMetaObjectPrivate::connect(co, sigIndex, smeta, o, i))) {
foundIt = true;
// ...and stop looking for further objects with the same name.
// Note: the Designer will make sure each object name is unique in the above
// 'list' but other code may create two child objects with the same name. In
// this case one is chosen 'at random'.
break;
}
}
if (foundIt) {
// we found our slot, now skip all overloads
while (mo->method(i + 1).attributes() & QMetaMethod::Cloned)
++i;
} else if (!(mo->method(i).attributes() & QMetaMethod::Cloned)) {
// check if the slot has the following signature: "on_..._...(..."
int iParen = slotSignature.indexOf('(');
int iLastUnderscore = slotSignature.lastIndexOf('_', iParen-1);
if (iLastUnderscore > 3)
qWarning("QMetaObject::connectSlotsByName: No matching signal for %s", slot);
}
}
}
/*!
\internal
\a signal must be in the signal index range (see QObjectPrivate::signalIndex()).
*/
static void queued_activate(QObject *sender, int signal, QObjectPrivate::Connection *c, void **argv,
QMutexLocker &locker)
{
const int *argumentTypes = c->argumentTypes.load();
if (!argumentTypes) {
QMetaMethod m = QMetaObjectPrivate::signal(sender->metaObject(), signal);
argumentTypes = queuedConnectionTypes(m.parameterTypes());
if (!argumentTypes) // cannot queue arguments
argumentTypes = &DIRECT_CONNECTION_ONLY;
if (!c->argumentTypes.testAndSetOrdered(0, argumentTypes)) {
if (argumentTypes != &DIRECT_CONNECTION_ONLY)
delete [] argumentTypes;
argumentTypes = c->argumentTypes.load();
}
}
if (argumentTypes == &DIRECT_CONNECTION_ONLY) // cannot activate
return;
int nargs = 1; // include return type
while (argumentTypes[nargs-1])
++nargs;
int *types = (int *) malloc(nargs*sizeof(int));
Q_CHECK_PTR(types);
void **args = (void **) malloc(nargs*sizeof(void *));
Q_CHECK_PTR(args);
types[0] = 0; // return type
args[0] = 0; // return value
if (nargs > 1) {
for (int n = 1; n < nargs; ++n)
types[n] = argumentTypes[n-1];
locker.unlock();
for (int n = 1; n < nargs; ++n)
args[n] = QMetaType::create(types[n], argv[n]);
locker.relock();
if (!c->receiver) {
locker.unlock();
// we have been disconnected while the mutex was unlocked
for (int n = 1; n < nargs; ++n)
QMetaType::destroy(types[n], args[n]);
free(types);
free(args);
locker.relock();
return;
}
}
QMetaCallEvent *ev = c->isSlotObject ?
new QMetaCallEvent(c->slotObj, sender, signal, nargs, types, args) :
new QMetaCallEvent(c->method_offset, c->method_relative, c->callFunction, sender, signal, nargs, types, args);
QCoreApplication::postEvent(c->receiver, ev);
}
/*!
\internal
*/
void QMetaObject::activate(QObject *sender, const QMetaObject *m, int local_signal_index,
void **argv)
{
activate(sender, QMetaObjectPrivate::signalOffset(m), local_signal_index, argv);
}
/*!
\internal
*/
void QMetaObject::activate(QObject *sender, int signalOffset, int local_signal_index, void **argv)
{
int signal_index = signalOffset + local_signal_index;
if (sender->d_func()->blockSig)
return;
Q_TRACE_SCOPE(QMetaObject_activate, sender, signal_index);
if (sender->d_func()->isDeclarativeSignalConnected(signal_index)
&& QAbstractDeclarativeData::signalEmitted) {
Q_TRACE_SCOPE(QMetaObject_activate_declarative_signal, sender, signal_index);
QAbstractDeclarativeData::signalEmitted(sender->d_func()->declarativeData, sender,
signal_index, argv);
}
if (!sender->d_func()->isSignalConnected(signal_index, /*checkDeclarative =*/ false)
&& !qt_signal_spy_callback_set.signal_begin_callback
&& !qt_signal_spy_callback_set.signal_end_callback) {
// The possible declarative connection is done, and nothing else is connected, so:
return;
}
void *empty_argv[] = { 0 };
if (qt_signal_spy_callback_set.signal_begin_callback != 0) {
qt_signal_spy_callback_set.signal_begin_callback(sender, signal_index,
argv ? argv : empty_argv);
}
{
QMutexLocker locker(signalSlotLock(sender));
struct ConnectionListsRef {
QObjectConnectionListVector *connectionLists;
ConnectionListsRef(QObjectConnectionListVector *connectionLists) : connectionLists(connectionLists)
{
if (connectionLists)
++connectionLists->inUse;
}
~ConnectionListsRef()
{
if (!connectionLists)
return;
--connectionLists->inUse;
Q_ASSERT(connectionLists->inUse >= 0);
if (connectionLists->orphaned) {
if (!connectionLists->inUse)
delete connectionLists;
}
}
QObjectConnectionListVector *operator->() const { return connectionLists; }
};
ConnectionListsRef connectionLists = sender->d_func()->connectionLists;
if (!connectionLists.connectionLists) {
locker.unlock();
if (qt_signal_spy_callback_set.signal_end_callback != 0)
qt_signal_spy_callback_set.signal_end_callback(sender, signal_index);
return;
}
const QObjectPrivate::ConnectionList *list;
if (signal_index < connectionLists->count())
list = &connectionLists->at(signal_index);
else
list = &connectionLists->allsignals;
Qt::HANDLE currentThreadId = QThread::currentThreadId();
do {
QObjectPrivate::Connection *c = list->first;
if (!c) continue;
// We need to check against last here to ensure that signals added
// during the signal emission are not emitted in this emission.
QObjectPrivate::Connection *last = list->last;
do {
if (!c->receiver)
continue;
QObject * const receiver = c->receiver;
const bool receiverInSameThread = currentThreadId == receiver->d_func()->threadData->threadId.load();
// determine if this connection should be sent immediately or
// put into the event queue
if ((c->connectionType == Qt::AutoConnection && !receiverInSameThread)
|| (c->connectionType == Qt::QueuedConnection)) {
queued_activate(sender, signal_index, c, argv ? argv : empty_argv, locker);
continue;
#if QT_CONFIG(thread)
} else if (c->connectionType == Qt::BlockingQueuedConnection) {
if (receiverInSameThread) {
qWarning("Qt: Dead lock detected while activating a BlockingQueuedConnection: "
"Sender is %s(%p), receiver is %s(%p)",
sender->metaObject()->className(), sender,
receiver->metaObject()->className(), receiver);
}
QSemaphore semaphore;
QMetaCallEvent *ev = c->isSlotObject ?
new QMetaCallEvent(c->slotObj, sender, signal_index, 0, 0, argv ? argv : empty_argv, &semaphore) :
new QMetaCallEvent(c->method_offset, c->method_relative, c->callFunction, sender, signal_index, 0, 0, argv ? argv : empty_argv, &semaphore);
QCoreApplication::postEvent(receiver, ev);
locker.unlock();
semaphore.acquire();
locker.relock();
continue;
#endif
}
QConnectionSenderSwitcher sw;
if (receiverInSameThread) {
sw.switchSender(receiver, sender, signal_index);
}
if (c->isSlotObject) {
c->slotObj->ref();
QScopedPointer<QtPrivate::QSlotObjectBase, QSlotObjectBaseDeleter> obj(c->slotObj);
locker.unlock();
{
Q_TRACE_SCOPE(QMetaObject_activate_slot_functor, obj.data());
obj->call(receiver, argv ? argv : empty_argv);
}
// Make sure the slot object gets destroyed before the mutex is locked again, as the
// destructor of the slot object might also lock a mutex from the signalSlotLock() mutex pool,
// and that would deadlock if the pool happens to return the same mutex.
obj.reset();
locker.relock();
} else if (c->callFunction && c->method_offset <= receiver->metaObject()->methodOffset()) {
//we compare the vtable to make sure we are not in the destructor of the object.
const int methodIndex = c->method();
const int method_relative = c->method_relative;
const auto callFunction = c->callFunction;
locker.unlock();
if (qt_signal_spy_callback_set.slot_begin_callback != 0)
qt_signal_spy_callback_set.slot_begin_callback(receiver, methodIndex, argv ? argv : empty_argv);
{
Q_TRACE_SCOPE(QMetaObject_activate_slot, receiver, methodIndex);
callFunction(receiver, QMetaObject::InvokeMetaMethod, method_relative, argv ? argv : empty_argv);
}
if (qt_signal_spy_callback_set.slot_end_callback != 0)
qt_signal_spy_callback_set.slot_end_callback(receiver, methodIndex);
locker.relock();
} else {
const int method = c->method_relative + c->method_offset;
locker.unlock();
if (qt_signal_spy_callback_set.slot_begin_callback != 0) {
qt_signal_spy_callback_set.slot_begin_callback(receiver,
method,
argv ? argv : empty_argv);
}
{
Q_TRACE_SCOPE(QMetaObject_activate_slot, receiver, method);
metacall(receiver, QMetaObject::InvokeMetaMethod, method, argv ? argv : empty_argv);
}
if (qt_signal_spy_callback_set.slot_end_callback != 0)
qt_signal_spy_callback_set.slot_end_callback(receiver, method);
locker.relock();
}
if (connectionLists->orphaned)
break;
} while (c != last && (c = c->nextConnectionList) != 0);
if (connectionLists->orphaned)
break;
} while (list != &connectionLists->allsignals &&
//start over for all signals;
((list = &connectionLists->allsignals), true));
}
if (qt_signal_spy_callback_set.signal_end_callback != 0)
qt_signal_spy_callback_set.signal_end_callback(sender, signal_index);
}
/*!
\internal
signal_index comes from indexOfMethod()
*/
void QMetaObject::activate(QObject *sender, int signal_index, void **argv)
{
const QMetaObject *mo = sender->metaObject();
while (mo->methodOffset() > signal_index)
mo = mo->superClass();
activate(sender, mo, signal_index - mo->methodOffset(), argv);
}
/*!
\internal
Returns the signal index used in the internal connectionLists vector.
It is different from QMetaObject::indexOfSignal(): indexOfSignal is the same as indexOfMethod
while QObjectPrivate::signalIndex is smaller because it doesn't give index to slots.
If \a meta is not 0, it is set to the meta-object where the signal was found.
*/
int QObjectPrivate::signalIndex(const char *signalName,
const QMetaObject **meta) const
{
Q_Q(const QObject);
const QMetaObject *base = q->metaObject();
Q_ASSERT(QMetaObjectPrivate::get(base)->revision >= 7);
QArgumentTypeArray types;
QByteArray name = QMetaObjectPrivate::decodeMethodSignature(signalName, types);
int relative_index = QMetaObjectPrivate::indexOfSignalRelative(
&base, name, types.size(), types.constData());
if (relative_index < 0)
return relative_index;
relative_index = QMetaObjectPrivate::originalClone(base, relative_index);
if (meta)
*meta = base;
return relative_index + QMetaObjectPrivate::signalOffset(base);
}
/*****************************************************************************
Properties
*****************************************************************************/
#ifndef QT_NO_PROPERTIES
/*!
Sets the value of the object's \a name property to \a value.
If the property is defined in the class using Q_PROPERTY then
true is returned on success and false otherwise. If the property
is not defined using Q_PROPERTY, and therefore not listed in the
meta-object, it is added as a dynamic property and false is returned.
Information about all available properties is provided through the
metaObject() and dynamicPropertyNames().
Dynamic properties can be queried again using property() and can be
removed by setting the property value to an invalid QVariant.
Changing the value of a dynamic property causes a QDynamicPropertyChangeEvent
to be sent to the object.
\b{Note:} Dynamic properties starting with "_q_" are reserved for internal
purposes.
\sa property(), metaObject(), dynamicPropertyNames(), QMetaProperty::write()
*/
bool QObject::setProperty(const char *name, const QVariant &value)
{
Q_D(QObject);
const QMetaObject* meta = metaObject();
if (!name || !meta)
return false;
int id = meta->indexOfProperty(name);
if (id < 0) {
if (!d->extraData)
d->extraData = new QObjectPrivate::ExtraData;
const int idx = d->extraData->propertyNames.indexOf(name);
if (!value.isValid()) {
if (idx == -1)
return false;
d->extraData->propertyNames.removeAt(idx);
d->extraData->propertyValues.removeAt(idx);
} else {
if (idx == -1) {
d->extraData->propertyNames.append(name);
d->extraData->propertyValues.append(value);
} else {
if (value.userType() == d->extraData->propertyValues.at(idx).userType()
&& value == d->extraData->propertyValues.at(idx))
return false;
d->extraData->propertyValues[idx] = value;
}
}
QDynamicPropertyChangeEvent ev(name);
QCoreApplication::sendEvent(this, &ev);
return false;
}
QMetaProperty p = meta->property(id);
#ifndef QT_NO_DEBUG
if (!p.isWritable())
qWarning("%s::setProperty: Property \"%s\" invalid,"
" read-only or does not exist", metaObject()->className(), name);
#endif
return p.write(this, value);
}
/*!
Returns the value of the object's \a name property.
If no such property exists, the returned variant is invalid.
Information about all available properties is provided through the
metaObject() and dynamicPropertyNames().
\sa setProperty(), QVariant::isValid(), metaObject(), dynamicPropertyNames()
*/
QVariant QObject::property(const char *name) const
{
Q_D(const QObject);
const QMetaObject* meta = metaObject();
if (!name || !meta)
return QVariant();
int id = meta->indexOfProperty(name);
if (id < 0) {
if (!d->extraData)
return QVariant();
const int i = d->extraData->propertyNames.indexOf(name);
return d->extraData->propertyValues.value(i);
}
QMetaProperty p = meta->property(id);
#ifndef QT_NO_DEBUG
if (!p.isReadable())
qWarning("%s::property: Property \"%s\" invalid or does not exist",
metaObject()->className(), name);
#endif
return p.read(this);
}
/*!
\since 4.2
Returns the names of all properties that were dynamically added to
the object using setProperty().
*/
QList<QByteArray> QObject::dynamicPropertyNames() const
{
Q_D(const QObject);
if (d->extraData)
return d->extraData->propertyNames;
return QList<QByteArray>();
}
#endif // QT_NO_PROPERTIES
/*****************************************************************************
QObject debugging output routines.
*****************************************************************************/
static void dumpRecursive(int level, const QObject *object)
{
if (object) {
QByteArray buf;
buf.fill(' ', level / 2 * 8);
if (level % 2)
buf += " ";
QString name = object->objectName();
QString flags = QLatin1String("");
#if 0
if (qApp->focusWidget() == object)
flags += 'F';
if (object->isWidgetType()) {
QWidget * w = (QWidget *)object;
if (w->isVisible()) {
QString t("<%1,%2,%3,%4>");
flags += t.arg(w->x()).arg(w->y()).arg(w->width()).arg(w->height());
} else {
flags += 'I';
}
}
#endif
qDebug("%s%s::%s %s", (const char*)buf, object->metaObject()->className(), name.toLocal8Bit().data(),
flags.toLatin1().data());
QObjectList children = object->children();
if (!children.isEmpty()) {
for (int i = 0; i < children.size(); ++i)
dumpRecursive(level+1, children.at(i));
}
}
}
/*!
\overload
\obsolete
Dumps a tree of children to the debug output.
\sa dumpObjectInfo()
*/
void QObject::dumpObjectTree()
{
const_cast<const QObject *>(this)->dumpObjectTree();
}
/*!
Dumps a tree of children to the debug output.
\note before Qt 5.9, this function was not const.
\sa dumpObjectInfo()
*/
void QObject::dumpObjectTree() const
{
dumpRecursive(0, this);
}
/*!
\overload
\obsolete
Dumps information about signal connections, etc. for this object
to the debug output.
\sa dumpObjectTree()
*/
void QObject::dumpObjectInfo()
{
const_cast<const QObject *>(this)->dumpObjectInfo();
}
/*!
Dumps information about signal connections, etc. for this object
to the debug output.
\note before Qt 5.9, this function was not const.
\sa dumpObjectTree()
*/
void QObject::dumpObjectInfo() const
{
qDebug("OBJECT %s::%s", metaObject()->className(),
objectName().isEmpty() ? "unnamed" : objectName().toLocal8Bit().data());
Q_D(const QObject);
QMutexLocker locker(signalSlotLock(this));
// first, look for connections where this object is the sender
qDebug(" SIGNALS OUT");
if (d->connectionLists) {
for (int signal_index = 0; signal_index < d->connectionLists->count(); ++signal_index) {
const QMetaMethod signal = QMetaObjectPrivate::signal(metaObject(), signal_index);
qDebug(" signal: %s", signal.methodSignature().constData());
// receivers
const QObjectPrivate::Connection *c =
d->connectionLists->at(signal_index).first;
while (c) {
if (!c->receiver) {
qDebug(" <Disconnected receiver>");
c = c->nextConnectionList;
continue;
}
if (c->isSlotObject) {
qDebug(" <functor or function pointer>");
c = c->nextConnectionList;
continue;
}
const QMetaObject *receiverMetaObject = c->receiver->metaObject();
const QMetaMethod method = receiverMetaObject->method(c->method());
qDebug(" --> %s::%s %s",
receiverMetaObject->className(),
c->receiver->objectName().isEmpty() ? "unnamed" : qPrintable(c->receiver->objectName()),
method.methodSignature().constData());
c = c->nextConnectionList;
}
}
} else {
qDebug( " <None>" );
}
// now look for connections where this object is the receiver
qDebug(" SIGNALS IN");
if (d->senders) {
for (QObjectPrivate::Connection *s = d->senders; s; s = s->next) {
QByteArray slotName = QByteArrayLiteral("<unknown>");
if (!s->isSlotObject) {
const QMetaMethod slot = metaObject()->method(s->method());
slotName = slot.methodSignature();
}
qDebug(" <-- %s::%s %s",
s->sender->metaObject()->className(),
s->sender->objectName().isEmpty() ? "unnamed" : qPrintable(s->sender->objectName()),
slotName.constData());
}
} else {
qDebug(" <None>");
}
}
#ifndef QT_NO_USERDATA
/*!
\internal
*/
uint QObject::registerUserData()
{
static int user_data_registration = 0;
return user_data_registration++;
}
/*!
\internal
*/
QObjectUserData::~QObjectUserData()
{
}
/*!
\internal
*/
void QObject::setUserData(uint id, QObjectUserData* data)
{
Q_D(QObject);
if (!d->extraData)
d->extraData = new QObjectPrivate::ExtraData;
if (d->extraData->userData.size() <= (int) id)
d->extraData->userData.resize((int) id + 1);
d->extraData->userData[id] = data;
}
/*!
\internal
*/
QObjectUserData* QObject::userData(uint id) const
{
Q_D(const QObject);
if (!d->extraData)
return 0;
if ((int)id < d->extraData->userData.size())
return d->extraData->userData.at(id);
return 0;
}
#endif // QT_NO_USERDATA
#ifndef QT_NO_DEBUG_STREAM
QDebug operator<<(QDebug dbg, const QObject *o)
{
QDebugStateSaver saver(dbg);
if (!o)
return dbg << "QObject(0x0)";
dbg.nospace() << o->metaObject()->className() << '(' << (const void *)o;
if (!o->objectName().isEmpty())
dbg << ", name = " << o->objectName();
dbg << ')';
return dbg;
}
#endif
/*!
\macro Q_CLASSINFO(Name, Value)
\relates QObject
This macro associates extra information to the class, which is available
using QObject::metaObject(). Qt makes only limited use of this feature, in
the \l{Active Qt}, \l{Qt D-Bus} and \l{Qt QML module}{Qt QML}.
The extra information takes the form of a \a Name string and a \a Value
literal string.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 35
\sa QMetaObject::classInfo()
\sa QAxFactory
\sa {Using Qt D-Bus Adaptors}
\sa {Extending QML}
*/
/*!
\macro Q_INTERFACES(...)
\relates QObject
This macro tells Qt which interfaces the class implements. This
is used when implementing plugins.
Example:
\snippet ../widgets/tools/plugandpaint/plugins/basictools/basictoolsplugin.h 1
\dots
\snippet ../widgets/tools/plugandpaint/plugins/basictools/basictoolsplugin.h 3
See the \l{tools/plugandpaint/plugins/basictools}{Plug & Paint
Basic Tools} example for details.
\sa Q_DECLARE_INTERFACE(), Q_PLUGIN_METADATA(), {How to Create Qt Plugins}
*/
/*!
\macro Q_PROPERTY(...)
\relates QObject
This macro is used for declaring properties in classes that
inherit QObject. Properties behave like class data members, but
they have additional features accessible through the \l
{Meta-Object System}.
\snippet code/doc_src_properties.cpp 0
The property name and type and the \c READ function are required.
The type can be any type supported by QVariant, or it can be a
user-defined type. The other items are optional, but a \c WRITE
function is common. The attributes default to true except \c USER,
which defaults to false.
For example:
\snippet code/src_corelib_kernel_qobject.cpp 37
For more details about how to use this macro, and a more detailed
example of its use, see the discussion on \l {Qt's Property System}.
\sa {Qt's Property System}
*/
/*!
\macro Q_ENUMS(...)
\relates QObject
\obsolete
This macro registers one or several enum types to the meta-object
system.
For example:
\snippet code/src_corelib_kernel_qobject.cpp 38
If you want to register an enum that is declared in another class,
the enum must be fully qualified with the name of the class
defining it. In addition, the class \e defining the enum has to
inherit QObject as well as declare the enum using Q_ENUMS().
In new code, you should prefer the use of the Q_ENUM() macro, which makes the
type available also to the meta type system.
For instance, QMetaEnum::fromType() will not work with types declared with Q_ENUMS().
\sa {Qt's Property System}
*/
/*!
\macro Q_FLAGS(...)
\relates QObject
\obsolete
This macro registers one or several \l{QFlags}{flags types} with the
meta-object system. It is typically used in a class definition to declare
that values of a given enum can be used as flags and combined using the
bitwise OR operator.
\note This macro takes care of registering individual flag values
with the meta-object system, so it is unnecessary to use Q_ENUMS()
in addition to this macro.
In new code, you should prefer the use of the Q_FLAG() macro, which makes the
type available also to the meta type system.
\sa {Qt's Property System}
*/
/*!
\macro Q_ENUM(...)
\relates QObject
\since 5.5
This macro registers an enum type with the meta-object system.
It must be placed after the enum declaration in a class that has the Q_OBJECT or the
Q_GADGET macro. For namespaces use \l Q_ENUM_NS() instead.
For example:
\snippet code/src_corelib_kernel_qobject.cpp 38
Enumerations that are declared with Q_ENUM have their QMetaEnum registered in the
enclosing QMetaObject. You can also use QMetaEnum::fromType() to get the QMetaEnum.
Registered enumerations are automatically registered also to the Qt meta
type system, making them known to QMetaType without the need to use
Q_DECLARE_METATYPE(). This will enable useful features; for example, if used
in a QVariant, you can convert them to strings. Likewise, passing them to
QDebug will print out their names.
Mind that the enum values are stored as signed \c int in the meta object system.
Registering enumerations with values outside the range of values valid for \c int
will lead to overflows and potentially undefined behavior when accessing them through
the meta object system. QML, for example, does access registered enumerations through
the meta object system.
\sa {Qt's Property System}
*/
/*!
\macro Q_FLAG(...)
\relates QObject
\since 5.5
This macro registers a single \l{QFlags}{flags type} with the
meta-object system. It is typically used in a class definition to declare
that values of a given enum can be used as flags and combined using the
bitwise OR operator. For namespaces use \l Q_FLAG_NS() instead.
The macro must be placed after the enum declaration.
For example, in QLibrary, the \l{QLibrary::LoadHints}{LoadHints} flag is
declared in the following way:
\snippet code/src_corelib_kernel_qobject.cpp 39
The declaration of the flags themselves is performed in the public section
of the QLibrary class itself, using the \l Q_DECLARE_FLAGS() macro.
\note The Q_FLAG macro takes care of registering individual flag values
with the meta-object system, so it is unnecessary to use Q_ENUM()
in addition to this macro.
\sa {Qt's Property System}
*/
/*!
\macro Q_ENUM_NS(...)
\relates QObject
\since 5.8
This macro registers an enum type with the meta-object system.
It must be placed after the enum declaration in a namespace that
has the Q_NAMESPACE macro. It is the same as \l Q_ENUM but in a
namespace.
Enumerations that are declared with Q_ENUM_NS have their QMetaEnum
registered in the enclosing QMetaObject. You can also use
QMetaEnum::fromType() to get the QMetaEnum.
Registered enumerations are automatically registered also to the Qt meta
type system, making them known to QMetaType without the need to use
Q_DECLARE_METATYPE(). This will enable useful features; for example, if
used in a QVariant, you can convert them to strings. Likewise, passing them
to QDebug will print out their names.
Mind that the enum values are stored as signed \c int in the meta object system.
Registering enumerations with values outside the range of values valid for \c int
will lead to overflows and potentially undefined behavior when accessing them through
the meta object system. QML, for example, does access registered enumerations through
the meta object system.
\sa {Qt's Property System}
*/
/*!
\macro Q_FLAG_NS(...)
\relates QObject
\since 5.8
This macro registers a single \l{QFlags}{flags type} with the
meta-object system. It is used in a namespace that has the
Q_NAMESPACE macro, to declare that values of a given enum can be
used as flags and combined using the bitwise OR operator.
It is the same as \l Q_FLAG but in a namespace.
The macro must be placed after the enum declaration.
\note The Q_FLAG_NS macro takes care of registering individual flag
values with the meta-object system, so it is unnecessary to use
Q_ENUM_NS() in addition to this macro.
\sa {Qt's Property System}
*/
/*!
\macro Q_OBJECT
\relates QObject
The Q_OBJECT macro must appear in the private section of a class
definition that declares its own signals and slots or that uses
other services provided by Qt's meta-object system.
For example:
\snippet signalsandslots/signalsandslots.h 1
\codeline
\snippet signalsandslots/signalsandslots.h 2
\snippet signalsandslots/signalsandslots.h 3
\note This macro requires the class to be a subclass of QObject. Use
Q_GADGET instead of Q_OBJECT to enable the meta object system's support
for enums in a class that is not a QObject subclass.
\sa {Meta-Object System}, {Signals and Slots}, {Qt's Property System}
*/
/*!
\macro Q_GADGET
\relates QObject
The Q_GADGET macro is a lighter version of the Q_OBJECT macro for classes
that do not inherit from QObject but still want to use some of the
reflection capabilities offered by QMetaObject. Just like the Q_OBJECT
macro, it must appear in the private section of a class definition.
Q_GADGETs can have Q_ENUM, Q_PROPERTY and Q_INVOKABLE, but they cannot have
signals or slots.
Q_GADGET makes a class member, \c{staticMetaObject}, available.
\c{staticMetaObject} is of type QMetaObject and provides access to the
enums declared with Q_ENUMS.
*/
/*!
\macro Q_NAMESPACE
\relates QObject
\since 5.8
The Q_NAMESPACE macro can be used to add QMetaObject capabilities
to a namespace.
Q_NAMESPACEs can have Q_CLASSINFO, Q_ENUM_NS, Q_FLAG_NS, but they
cannot have Q_ENUM, Q_FLAG, Q_PROPERTY, Q_INVOKABLE, signals nor slots.
Q_NAMESPACE makes an external variable, \c{staticMetaObject}, available.
\c{staticMetaObject} is of type QMetaObject and provides access to the
enums declared with Q_ENUM_NS/Q_FLAG_NS.
*/
/*!
\macro Q_SIGNALS
\relates QObject
Use this macro to replace the \c signals keyword in class
declarations, when you want to use Qt Signals and Slots with a
\l{3rd Party Signals and Slots} {3rd party signal/slot mechanism}.
The macro is normally used when \c no_keywords is specified with
the \c CONFIG variable in the \c .pro file, but it can be used
even when \c no_keywords is \e not specified.
*/
/*!
\macro Q_SIGNAL
\relates QObject
This is an additional macro that allows you to mark a single
function as a signal. It can be quite useful, especially when you
use a 3rd-party source code parser which doesn't understand a \c
signals or \c Q_SIGNALS groups.
Use this macro to replace the \c signals keyword in class
declarations, when you want to use Qt Signals and Slots with a
\l{3rd Party Signals and Slots} {3rd party signal/slot mechanism}.
The macro is normally used when \c no_keywords is specified with
the \c CONFIG variable in the \c .pro file, but it can be used
even when \c no_keywords is \e not specified.
*/
/*!
\macro Q_SLOTS
\relates QObject
Use this macro to replace the \c slots keyword in class
declarations, when you want to use Qt Signals and Slots with a
\l{3rd Party Signals and Slots} {3rd party signal/slot mechanism}.
The macro is normally used when \c no_keywords is specified with
the \c CONFIG variable in the \c .pro file, but it can be used
even when \c no_keywords is \e not specified.
*/
/*!
\macro Q_SLOT
\relates QObject
This is an additional macro that allows you to mark a single
function as a slot. It can be quite useful, especially when you
use a 3rd-party source code parser which doesn't understand a \c
slots or \c Q_SLOTS groups.
Use this macro to replace the \c slots keyword in class
declarations, when you want to use Qt Signals and Slots with a
\l{3rd Party Signals and Slots} {3rd party signal/slot mechanism}.
The macro is normally used when \c no_keywords is specified with
the \c CONFIG variable in the \c .pro file, but it can be used
even when \c no_keywords is \e not specified.
*/
/*!
\macro Q_EMIT
\relates QObject
Use this macro to replace the \c emit keyword for emitting
signals, when you want to use Qt Signals and Slots with a
\l{3rd Party Signals and Slots} {3rd party signal/slot mechanism}.
The macro is normally used when \c no_keywords is specified with
the \c CONFIG variable in the \c .pro file, but it can be used
even when \c no_keywords is \e not specified.
*/
/*!
\macro Q_INVOKABLE
\relates QObject
Apply this macro to declarations of member functions to allow them to
be invoked via the meta-object system. The macro is written before
the return type, as shown in the following example:
\snippet qmetaobject-invokable/window.h Window class with invokable method
The \c invokableMethod() function is marked up using Q_INVOKABLE, causing
it to be registered with the meta-object system and enabling it to be
invoked using QMetaObject::invokeMethod().
Since \c normalMethod() function is not registered in this way, it cannot
be invoked using QMetaObject::invokeMethod().
If an invokable member function returns a pointer to a QObject or a
subclass of QObject and it is invoked from QML, special ownership rules
apply. See \l{qtqml-cppintegration-data.html}{Data Type Conversion Between QML and C++}
for more information.
*/
/*!
\macro Q_REVISION
\relates QObject
Apply this macro to declarations of member functions to tag them with a
revision number in the meta-object system. The macro is written before
the return type, as shown in the following example:
\snippet qmetaobject-revision/window.h Window class with revision
This is useful when using the meta-object system to dynamically expose
objects to another API, as you can match the version expected by multiple
versions of the other API. Consider the following simplified example:
\snippet qmetaobject-revision/main.cpp Window class using revision
Using the same Window class as the previous example, the newProperty and
newMethod would only be exposed in this code when the expected version is
1 or greater.
Since all methods are considered to be in revision 0 if untagged, a tag
of Q_REVISION(0) is invalid and ignored.
This tag is not used by the meta-object system itself. Currently this is only
used by the QtQml module.
For a more generic string tag, see \l QMetaMethod::tag()
\sa QMetaMethod::revision()
*/
/*!
\macro Q_SET_OBJECT_NAME(Object)
\relates QObject
\since 5.0
This macro assigns \a Object the objectName "Object".
It doesn't matter whether \a Object is a pointer or not, the
macro figures that out by itself.
\sa QObject::objectName()
*/
/*!
\macro QT_NO_NARROWING_CONVERSIONS_IN_CONNECT
\relates QObject
\since 5.8
Defining this macro will disable narrowing and floating-point-to-integral
conversions between the arguments carried by a signal and the arguments
accepted by a slot, when the signal and the slot are connected using the
PMF-based syntax.
\sa QObject::connect
*/
/*!
\typedef QObjectList
\relates QObject
Synonym for QList<QObject *>.
*/
void qDeleteInEventHandler(QObject *o)
{
delete o;
}
/*!
\fn template<typename PointerToMemberFunction> QMetaObject::Connection QObject::connect(const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method, Qt::ConnectionType type)
\overload connect()
\threadsafe
Creates a connection of the given \a type from the \a signal in
the \a sender object to the \a method in the \a receiver object.
Returns a handle to the connection that can be used to disconnect
it later.
The signal must be a function declared as a signal in the header.
The slot function can be any member function that can be connected
to the signal.
A slot can be connected to a given signal if the signal has at
least as many arguments as the slot, and there is an implicit
conversion between the types of the corresponding arguments in the
signal and the slot.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 44
This example ensures that the label always displays the current
line edit text.
A signal can be connected to many slots and signals. Many signals
can be connected to one slot.
If a signal is connected to several slots, the slots are activated
in the same order as the order the connection was made, when the
signal is emitted
The function returns an handle to a connection if it successfully
connects the signal to the slot. The Connection handle will be invalid
if it cannot create the connection, for example, if QObject is unable
to verify the existence of \a signal (if it was not declared as a signal)
You can check if the QMetaObject::Connection is valid by casting it to a bool.
By default, a signal is emitted for every connection you make;
two signals are emitted for duplicate connections. You can break
all of these connections with a single disconnect() call.
If you pass the Qt::UniqueConnection \a type, the connection will only
be made if it is not a duplicate. If there is already a duplicate
(exact same signal to the exact same slot on the same objects),
the connection will fail and connect will return an invalid QMetaObject::Connection.
The optional \a type parameter describes the type of connection
to establish. In particular, it determines whether a particular
signal is delivered to a slot immediately or queued for delivery
at a later time. If the signal is queued, the parameters must be
of types that are known to Qt's meta-object system, because Qt
needs to copy the arguments to store them in an event behind the
scenes. If you try to use a queued connection and get the error
message
\snippet code/src_corelib_kernel_qobject.cpp 25
make sure to declare the argument type with Q_DECLARE_METATYPE
Overloaded functions can be resolved with help of \l qOverload.
\sa {Differences between String-Based and Functor-Based Connections}
*/
/*!
\fn template<typename PointerToMemberFunction, typename Functor> QMetaObject::Connection QObject::connect(const QObject *sender, PointerToMemberFunction signal, Functor functor)
\threadsafe
\overload connect()
Creates a connection from \a signal in
\a sender object to \a functor, and returns a handle to the connection
The signal must be a function declared as a signal in the header.
The slot function can be any function or functor that can be connected
to the signal.
A function can be connected to a given signal if the signal has at
least as many argument as the slot. A functor can be connected to a signal
if they have exactly the same number of arguments. There must exist implicit
conversion between the types of the corresponding arguments in the
signal and the slot.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 45
Lambda expressions can also be used:
\snippet code/src_corelib_kernel_qobject.cpp 46
The connection will automatically disconnect if the sender is destroyed.
However, you should take care that any objects used within the functor
are still alive when the signal is emitted.
Overloaded functions can be resolved with help of \l qOverload.
*/
/*!
\fn template<typename PointerToMemberFunction, typename Functor> QMetaObject::Connection QObject::connect(const QObject *sender, PointerToMemberFunction signal, const QObject *context, Functor functor, Qt::ConnectionType type)
\threadsafe
\overload connect()
\since 5.2
Creates a connection of a given \a type from \a signal in
\a sender object to \a functor to be placed in a specific event
loop of \a context, and returns a handle to the connection.
\note Qt::UniqueConnections do not work for lambdas, non-member functions
and functors; they only apply to connecting to member functions.
The signal must be a function declared as a signal in the header.
The slot function can be any function or functor that can be connected
to the signal.
A function can be connected to a given signal if the signal has at
least as many argument as the slot. A functor can be connected to a signal
if they have exactly the same number of arguments. There must exist implicit
conversion between the types of the corresponding arguments in the
signal and the slot.
Example:
\snippet code/src_corelib_kernel_qobject.cpp 50
Lambda expressions can also be used:
\snippet code/src_corelib_kernel_qobject.cpp 51
The connection will automatically disconnect if the sender or the context
is destroyed.
However, you should take care that any objects used within the functor
are still alive when the signal is emitted.
Overloaded functions can be resolved with help of \l qOverload.
*/
/*!
\internal
Implementation of the template version of connect
\a sender is the sender object
\a signal is a pointer to a pointer to a member signal of the sender
\a receiver is the receiver object, may not be null, will be equal to sender when
connecting to a static function or a functor
\a slot a pointer only used when using Qt::UniqueConnection
\a type the Qt::ConnctionType passed as argument to connect
\a types an array of integer with the metatype id of the parameter of the signal
to be used with queued connection
must stay valid at least for the whole time of the connection, this function
do not take ownership. typically static data.
If null, then the types will be computed when the signal is emit in a queued
connection from the types from the signature.
\a senderMetaObject is the metaobject used to lookup the signal, the signal must be in
this metaobject
*/
QMetaObject::Connection QObject::connectImpl(const QObject *sender, void **signal,
const QObject *receiver, void **slot,
QtPrivate::QSlotObjectBase *slotObj, Qt::ConnectionType type,
const int *types, const QMetaObject *senderMetaObject)
{
if (!signal) {
qWarning("QObject::connect: invalid null parameter");
if (slotObj)
slotObj->destroyIfLastRef();
return QMetaObject::Connection();
}
int signal_index = -1;
void *args[] = { &signal_index, signal };
for (; senderMetaObject && signal_index < 0; senderMetaObject = senderMetaObject->superClass()) {
senderMetaObject->static_metacall(QMetaObject::IndexOfMethod, 0, args);
if (signal_index >= 0 && signal_index < QMetaObjectPrivate::get(senderMetaObject)->signalCount)
break;
}
if (!senderMetaObject) {
qWarning("QObject::connect: signal not found in %s", sender->metaObject()->className());
slotObj->destroyIfLastRef();
return QMetaObject::Connection(0);
}
signal_index += QMetaObjectPrivate::signalOffset(senderMetaObject);
return QObjectPrivate::connectImpl(sender, signal_index, receiver, slot, slotObj, type, types, senderMetaObject);
}
/*!
\internal
Internal version of connect used by the template version of QObject::connect (called via connectImpl) and
also used by the QObjectPrivate::connect version used by QML. The signal_index is expected to be relative
to the number of signals.
*/
QMetaObject::Connection QObjectPrivate::connectImpl(const QObject *sender, int signal_index,
const QObject *receiver, void **slot,
QtPrivate::QSlotObjectBase *slotObj, Qt::ConnectionType type,
const int *types, const QMetaObject *senderMetaObject)
{
if (!sender || !receiver || !slotObj || !senderMetaObject) {
const char *senderString = sender ? sender->metaObject()->className()
: senderMetaObject ? senderMetaObject->className()
: "Unknown";
const char *receiverString = receiver ? receiver->metaObject()->className()
: "Unknown";
qWarning("QObject::connect(%s, %s): invalid null parameter", senderString, receiverString);
if (slotObj)
slotObj->destroyIfLastRef();
return QMetaObject::Connection();
}
QObject *s = const_cast<QObject *>(sender);
QObject *r = const_cast<QObject *>(receiver);
QOrderedMutexLocker locker(signalSlotLock(sender),
signalSlotLock(receiver));
if (type & Qt::UniqueConnection && slot) {
QObjectConnectionListVector *connectionLists = QObjectPrivate::get(s)->connectionLists;
if (connectionLists && connectionLists->count() > signal_index) {
const QObjectPrivate::Connection *c2 =
(*connectionLists)[signal_index].first;
while (c2) {
if (c2->receiver == receiver && c2->isSlotObject && c2->slotObj->compare(slot)) {
slotObj->destroyIfLastRef();
return QMetaObject::Connection();
}
c2 = c2->nextConnectionList;
}
}
type = static_cast<Qt::ConnectionType>(type ^ Qt::UniqueConnection);
}
QScopedPointer<QObjectPrivate::Connection> c(new QObjectPrivate::Connection);
c->sender = s;
c->signal_index = signal_index;
c->receiver = r;
c->slotObj = slotObj;
c->connectionType = type;
c->isSlotObject = true;
if (types) {
c->argumentTypes.store(types);
c->ownArgumentTypes = false;
}
QObjectPrivate::get(s)->addConnection(signal_index, c.data());
QMetaObject::Connection ret(c.take());
locker.unlock();
QMetaMethod method = QMetaObjectPrivate::signal(senderMetaObject, signal_index);
Q_ASSERT(method.isValid());
s->connectNotify(method);
return ret;
}
/*!
Disconnect a connection.
If the \a connection is invalid or has already been disconnected, do nothing
and return false.
\sa connect()
*/
bool QObject::disconnect(const QMetaObject::Connection &connection)
{
QObjectPrivate::Connection *c = static_cast<QObjectPrivate::Connection *>(connection.d_ptr);
if (!c || !c->receiver)
return false;
QMutex *senderMutex = signalSlotLock(c->sender);
QMutex *receiverMutex = signalSlotLock(c->receiver);
{
QOrderedMutexLocker locker(senderMutex, receiverMutex);
QObjectConnectionListVector *connectionLists = QObjectPrivate::get(c->sender)->connectionLists;
Q_ASSERT(connectionLists);
connectionLists->dirty = true;
*c->prev = c->next;
if (c->next)
c->next->prev = c->prev;
c->receiver = 0;
}
// destroy the QSlotObject, if possible
if (c->isSlotObject) {
c->slotObj->destroyIfLastRef();
c->isSlotObject = false;
}
c->sender->disconnectNotify(QMetaObjectPrivate::signal(c->sender->metaObject(),
c->signal_index));
const_cast<QMetaObject::Connection &>(connection).d_ptr = 0;
c->deref(); // has been removed from the QMetaObject::Connection object
return true;
}
/*! \fn template<typename PointerToMemberFunction> bool QObject::disconnect(const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method)
\overload diconnect()
\threadsafe
Disconnects \a signal in object \a sender from \a method in object
\a receiver. Returns \c true if the connection is successfully broken;
otherwise returns \c false.
A signal-slot connection is removed when either of the objects
involved are destroyed.
disconnect() is typically used in three ways, as the following
examples demonstrate.
\list 1
\li Disconnect everything connected to an object's signals:
\snippet code/src_corelib_kernel_qobject.cpp 26
\li Disconnect everything connected to a specific signal:
\snippet code/src_corelib_kernel_qobject.cpp 47
\li Disconnect a specific receiver:
\snippet code/src_corelib_kernel_qobject.cpp 30
\li Disconnect a connection from one specific signal to a specific slot:
\snippet code/src_corelib_kernel_qobject.cpp 48
\endlist
0 may be used as a wildcard, meaning "any signal", "any receiving
object", or "any slot in the receiving object", respectively.
The \a sender may never be 0. (You cannot disconnect signals from
more than one object in a single call.)
If \a signal is 0, it disconnects \a receiver and \a method from
any signal. If not, only the specified signal is disconnected.
If \a receiver is 0, it disconnects anything connected to \a
signal. If not, slots in objects other than \a receiver are not
disconnected.
If \a method is 0, it disconnects anything that is connected to \a
receiver. If not, only slots named \a method will be disconnected,
and all other slots are left alone. The \a method must be 0 if \a
receiver is left out, so you cannot disconnect a
specifically-named slot on all objects.
\note It is not possible to use this overload to diconnect signals
connected to functors or lambda expressions. That is because it is not
possible to compare them. Instead, use the overload that takes a
QMetaObject::Connection
\sa connect()
*/
bool QObject::disconnectImpl(const QObject *sender, void **signal, const QObject *receiver, void **slot, const QMetaObject *senderMetaObject)
{
if (sender == 0 || (receiver == 0 && slot != 0)) {
qWarning("QObject::disconnect: Unexpected null parameter");
return false;
}
int signal_index = -1;
if (signal) {
void *args[] = { &signal_index, signal };
for (; senderMetaObject && signal_index < 0; senderMetaObject = senderMetaObject->superClass()) {
senderMetaObject->static_metacall(QMetaObject::IndexOfMethod, 0, args);
if (signal_index >= 0 && signal_index < QMetaObjectPrivate::get(senderMetaObject)->signalCount)
break;
}
if (!senderMetaObject) {
qWarning("QObject::disconnect: signal not found in %s", sender->metaObject()->className());
return QMetaObject::Connection(0);
}
signal_index += QMetaObjectPrivate::signalOffset(senderMetaObject);
}
return QMetaObjectPrivate::disconnect(sender, signal_index, senderMetaObject, receiver, -1, slot);
}
/*!
\internal
Used by QML to connect a signal by index to a slot implemented in JavaScript (wrapped in a custom QSlotOBjectBase subclass).
The signal_index is an index relative to the number of methods.
*/
QMetaObject::Connection QObjectPrivate::connect(const QObject *sender, int signal_index, QtPrivate::QSlotObjectBase *slotObj, Qt::ConnectionType type)
{
if (!sender) {
qWarning("QObject::connect: invalid null parameter");
if (slotObj)
slotObj->destroyIfLastRef();
return QMetaObject::Connection();
}
const QMetaObject *senderMetaObject = sender->metaObject();
signal_index = methodIndexToSignalIndex(&senderMetaObject, signal_index);
return QObjectPrivate::connectImpl(sender, signal_index, sender, /*slot*/0, slotObj, type, /*types*/0, senderMetaObject);
}
/*!
\internal
Used by QML to disconnect a signal by index that's connected to a slot implemented in JavaScript (wrapped in a custom QSlotObjectBase subclass)
In the QML case the slot is not a pointer to a pointer to the function to disconnect, but instead it is a pointer to an array of internal values
required for the disconnect.
*/
bool QObjectPrivate::disconnect(const QObject *sender, int signal_index, void **slot)
{
const QMetaObject *senderMetaObject = sender->metaObject();
signal_index = methodIndexToSignalIndex(&senderMetaObject, signal_index);
return QMetaObjectPrivate::disconnect(sender, signal_index, senderMetaObject, sender, -1, slot);
}
/*! \class QMetaObject::Connection
\inmodule QtCore
Represents a handle to a signal-slot (or signal-functor) connection.
It can be used to check if the connection is valid and to disconnect it using
QObject::disconnect(). For a signal-functor connection without a context object,
it is the only way to selectively disconnect that connection.
As Connection is just a handle, the underlying signal-slot connection is unaffected
when Connection is destroyed or reassigned.
*/
/*!
Create a copy of the handle to the \a other connection
*/
QMetaObject::Connection::Connection(const QMetaObject::Connection &other) : d_ptr(other.d_ptr)
{
if (d_ptr)
static_cast<QObjectPrivate::Connection *>(d_ptr)->ref();
}
/*!
Assigns \a other to this connection and returns a reference to this connection.
*/
QMetaObject::Connection& QMetaObject::Connection::operator=(const QMetaObject::Connection& other)
{
if (other.d_ptr != d_ptr) {
if (d_ptr)
static_cast<QObjectPrivate::Connection *>(d_ptr)->deref();
d_ptr = other.d_ptr;
if (other.d_ptr)
static_cast<QObjectPrivate::Connection *>(other.d_ptr)->ref();
}
return *this;
}
/*!
Creates a Connection instance.
*/
QMetaObject::Connection::Connection() : d_ptr(0) {}
/*!
Destructor for QMetaObject::Connection.
*/
QMetaObject::Connection::~Connection()
{
if (d_ptr)
static_cast<QObjectPrivate::Connection *>(d_ptr)->deref();
}
/*! \internal Returns true if the object is still connected */
bool QMetaObject::Connection::isConnected_helper() const
{
Q_ASSERT(d_ptr); // we're only called from operator RestrictedBool() const
QObjectPrivate::Connection *c = static_cast<QObjectPrivate::Connection *>(d_ptr);
return c->receiver;
}
/*!
\fn QMetaObject::Connection::operator bool() const
Returns \c true if the connection is valid.
The connection is valid if the call to QObject::connect succeeded.
The connection is invalid if QObject::connect was not able to find
the signal or the slot, or if the arguments do not match.
*/
QT_END_NAMESPACE
#include "moc_qnamespace.cpp"
#include "moc_qobject.cpp"
代码参考：https://www.qt.io
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QQ 3087438119
