qcoreevent.cpp

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// Copyright (C) 2022 The Qt Company Ltd.
// Copyright (C) 2016 Intel Corporation.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qcoreevent.h"
#include "qcoreevent_p.h"
#include "qcoreapplication.h"
#include "qcoreapplication_p.h"
 
#include "qbasicatomic.h"
 
#include <qtcore_tracepoints_p.h>
 
#include <limits>
 
QT_BEGIN_NAMESPACE
 
Q_TRACE_POINT(qtcore, QEvent_ctor, QEvent *event, QEvent::Type type);
Q_TRACE_POINT(qtcore, QEvent_dtor, QEvent *event, QEvent::Type type);
 
/*!
    \class QEvent
    \inmodule QtCore
    \brief The QEvent class is the base class of all
    event classes. Event objects contain event parameters.
 
    \ingroup events
 
    Qt's main event loop (QCoreApplication::exec()) fetches native
    window system events from the event queue, translates them into
    QEvents, and sends the translated events to \l{QObject}s.
 
    In general, events come from the underlying window system
    (spontaneous() returns \c true), but it is also possible to manually
    send events using QCoreApplication::sendEvent() and
    QCoreApplication::postEvent() (spontaneous() returns \c false).
 
    \l {QObject}{QObjects} receive events by having their QObject::event() function
    called. The function can be reimplemented in subclasses to
    customize event handling and add additional event types;
    QWidget::event() is a notable example. By default, events are
    dispatched to event handlers like QObject::timerEvent() and
    QWidget::mouseMoveEvent(). QObject::installEventFilter() allows an
    object to intercept events destined for another object.
 
    The basic QEvent contains only an event type parameter and an
    "accept" flag.  The accept flag set with accept(), and cleared
    with ignore(). It is set by default, but don't rely on this as
    subclasses may choose to clear it in their constructor.
 
    Subclasses of QEvent contain additional parameters that describe
    the particular event.
 
    \sa QObject::event(), QObject::installEventFilter(),
        QCoreApplication::sendEvent(),
        QCoreApplication::postEvent(), QCoreApplication::processEvents()
*/
 
 
/*!
    \enum QEvent::Type
 
    This enum type defines the valid event types in Qt. The event
    types and the specialized classes for each type are as follows:
 
    \value None                             Not an event.
    \value ActionAdded                      A new action has been added (QActionEvent).
    \value ActionChanged                    An action has been changed (QActionEvent).
    \value ActionRemoved                    An action has been removed (QActionEvent).
    \value ActivationChange                 A widget's top-level window activation state has changed.
    \value ApplicationActivate              This enum has been deprecated. Use ApplicationStateChange instead.
    \value ApplicationActivated             This enum has been deprecated. Use ApplicationStateChange instead.
    \value ApplicationDeactivate            This enum has been deprecated. Use ApplicationStateChange instead.
    \value ApplicationFontChange            The default application font has changed.
    \value ApplicationLayoutDirectionChange The default application layout direction has changed.
    \value ApplicationPaletteChange         The default application palette has changed.
    \value ApplicationStateChange           The state of the application has changed.
    \value ApplicationWindowIconChange      The application's icon has changed.
    \value ChildAdded                       An object gets a child (QChildEvent).
    \value ChildPolished                    A widget child gets polished (QChildEvent).
    \value ChildRemoved                     An object loses a child (QChildEvent).
    \value [since 6.7] ChildWindowAdded     A child window was added to the window.
    \value [since 6.7] ChildWindowRemoved   A child window was removed from the window.
    \value Clipboard                        The clipboard contents have changed.
    \value Close                            Widget was closed (QCloseEvent).
    \value CloseSoftwareInputPanel          A widget wants to close the software input panel (SIP).
    \value ContentsRectChange               The margins of the widget's content rect changed.
    \value ContextMenu                      Context popup menu (QContextMenuEvent).
    \value CursorChange                     The widget's cursor has changed.
    \value DeferredDelete                   The object will be deleted after it has cleaned up (QDeferredDeleteEvent)
    \value [since 6.6] DevicePixelRatioChange
                                            The devicePixelRatio has changed for this widget's or window's underlying backing store.
    \value DragEnter                        The cursor enters a widget during a drag and drop operation (QDragEnterEvent).
    \value DragLeave                        The cursor leaves a widget during a drag and drop operation (QDragLeaveEvent).
    \value DragMove                         A drag and drop operation is in progress (QDragMoveEvent).
    \value Drop                             A drag and drop operation is completed (QDropEvent).
    \value DynamicPropertyChange            A dynamic property was added, changed, or removed from the object.
    \value EnabledChange                    Widget's enabled state has changed.
    \value Enter                            Mouse enters widget's boundaries (QEnterEvent).
    \value EnterEditFocus                   An editor widget gains focus for editing. \c QT_KEYPAD_NAVIGATION must be defined.
    \value EnterWhatsThisMode               Send to toplevel widgets when the application enters "What's This?" mode.
    \value Expose                           Sent to a window when its on-screen contents are invalidated and need to be flushed from the backing store.
    \value FileOpen                         File open request (QFileOpenEvent).
    \value FocusIn                          Widget or Window gains keyboard focus (QFocusEvent).
    \value FocusOut                         Widget or Window loses keyboard focus (QFocusEvent).
    \value FocusAboutToChange               Widget or Window focus is about to change (QFocusEvent)
    \value FontChange                       Widget's font has changed.
    \value Gesture                          A gesture was triggered (QGestureEvent).
    \value GestureOverride                  A gesture override was triggered (QGestureEvent).
    \value GrabKeyboard                     Item gains keyboard grab (QGraphicsItem only).
    \value GrabMouse                        Item gains mouse grab (QGraphicsItem only).
    \value GraphicsSceneContextMenu         Context popup menu over a graphics scene (QGraphicsSceneContextMenuEvent).
    \value GraphicsSceneDragEnter           The cursor enters a graphics scene during a drag and drop operation (QGraphicsSceneDragDropEvent).
    \value GraphicsSceneDragLeave           The cursor leaves a graphics scene during a drag and drop operation (QGraphicsSceneDragDropEvent).
    \value GraphicsSceneDragMove            A drag and drop operation is in progress over a scene (QGraphicsSceneDragDropEvent).
    \value GraphicsSceneDrop                A drag and drop operation is completed over a scene (QGraphicsSceneDragDropEvent).
    \value GraphicsSceneHelp                The user requests help for a graphics scene (QHelpEvent).
    \value GraphicsSceneHoverEnter          The mouse cursor enters a hover item in a graphics scene (QGraphicsSceneHoverEvent).
    \value GraphicsSceneHoverLeave          The mouse cursor leaves a hover item in a graphics scene (QGraphicsSceneHoverEvent).
    \value GraphicsSceneHoverMove           The mouse cursor moves inside a hover item in a graphics scene (QGraphicsSceneHoverEvent).
    \value GraphicsSceneMouseDoubleClick    Mouse press again (double click) in a graphics scene (QGraphicsSceneMouseEvent).
    \value GraphicsSceneMouseMove           Move mouse in a graphics scene (QGraphicsSceneMouseEvent).
    \value GraphicsSceneMousePress          Mouse press in a graphics scene (QGraphicsSceneMouseEvent).
    \value GraphicsSceneMouseRelease        Mouse release in a graphics scene (QGraphicsSceneMouseEvent).
    \value GraphicsSceneMove                Widget was moved (QGraphicsSceneMoveEvent).
    \value GraphicsSceneResize              Widget was resized (QGraphicsSceneResizeEvent).
    \value GraphicsSceneWheel               Mouse wheel rolled in a graphics scene (QGraphicsSceneWheelEvent).
    \value GraphicsSceneLeave               The cursor leaves a graphics scene (QGraphicsSceneWheelEvent).
    \value Hide                             Widget was hidden (QHideEvent).
    \value HideToParent                     A child widget has been hidden.
    \value HoverEnter                       The mouse cursor enters a hover widget (QHoverEvent).
    \value HoverLeave                       The mouse cursor leaves a hover widget (QHoverEvent).
    \value HoverMove                        The mouse cursor moves inside a hover widget (QHoverEvent).
    \value IconDrag                         The main icon of a window has been dragged away (QIconDragEvent).
    \value IconTextChange                   Widget's icon text has been changed. (Deprecated)
    \value InputMethod                      An input method is being used (QInputMethodEvent).
    \value InputMethodQuery                 A input method query event (QInputMethodQueryEvent)
    \value KeyboardLayoutChange             The keyboard layout has changed.
    \value KeyPress                         Key press (QKeyEvent).
    \value KeyRelease                       Key release (QKeyEvent).
    \value LanguageChange                   The application translation changed.
    \value LayoutDirectionChange            The direction of layouts changed.
    \value LayoutRequest                    Widget layout needs to be redone.
    \value Leave                            Mouse leaves widget's boundaries.
    \value LeaveEditFocus                   An editor widget loses focus for editing. QT_KEYPAD_NAVIGATION must be defined.
    \value LeaveWhatsThisMode               Send to toplevel widgets when the application leaves "What's This?" mode.
    \value LocaleChange                     The system locale has changed.
    \value NonClientAreaMouseButtonDblClick A mouse double click occurred outside the client area (QMouseEvent).
    \value NonClientAreaMouseButtonPress    A mouse button press occurred outside the client area (QMouseEvent).
    \value NonClientAreaMouseButtonRelease  A mouse button release occurred outside the client area (QMouseEvent).
    \value NonClientAreaMouseMove           A mouse move occurred outside the client area (QMouseEvent).
    \value MacSizeChange                    The user changed his widget sizes (\macos only).
    \value MetaCall                         An asynchronous method invocation via QMetaObject::invokeMethod().
    \value ModifiedChange                   Widgets modification state has been changed.
    \value MouseButtonDblClick              Mouse press again (QMouseEvent).
    \value MouseButtonPress                 Mouse press (QMouseEvent).
    \value MouseButtonRelease               Mouse release (QMouseEvent).
    \value MouseMove                        Mouse move (QMouseEvent).
    \value MouseTrackingChange              The mouse tracking state has changed.
    \value Move                             Widget's position changed (QMoveEvent).
    \value NativeGesture                    The system has detected a gesture (QNativeGestureEvent).
    \value OrientationChange                The screens orientation has changes (QScreenOrientationChangeEvent).
    \value Paint                            Screen update necessary (QPaintEvent).
    \value PaletteChange                    Palette of the widget changed.
    \value ParentAboutToChange              The object parent is about to change.
                                            Only sent to some object types, such as QWidget.
    \value ParentChange                     The object parent has changed.
                                            Only sent to some object types, such as QWidget.
    \value [since 6.7] ParentWindowAboutToChange The parent window is about to change.
    \value [since 6.7] ParentWindowChange   The parent window has changed.
    \value PlatformPanel                    A platform specific panel has been requested.
    \value PlatformSurface                  A native platform surface has been created or is about to be destroyed (QPlatformSurfaceEvent).
    \omitvalue Pointer
    \value Polish                           The widget is polished.
    \value PolishRequest                    The widget should be polished.
    \value QueryWhatsThis                   The widget should accept the event if it has "What's This?" help (QHelpEvent).
    \value Quit                             The application has exited.
    \value [since 5.4] ReadOnlyChange       Widget's read-only state has changed.
    \value RequestSoftwareInputPanel        A widget wants to open a software input panel (SIP).
    \value Resize                           Widget's size changed (QResizeEvent).
    \value ScrollPrepare                    The object needs to fill in its geometry information (QScrollPrepareEvent).
    \value Scroll                           The object needs to scroll to the supplied position (QScrollEvent).
    \value Shortcut                         Key press in child for shortcut key handling (QShortcutEvent).
    \value ShortcutOverride                 Key press in child, for overriding shortcut key handling (QKeyEvent).
                                            When a shortcut is about to trigger, \c ShortcutOverride
                                            is sent to the active window. This allows clients (e.g. widgets)
                                            to signal that they will handle the shortcut themselves, by
                                            accepting the event. If the shortcut override is accepted, the
                                            event is delivered as a normal key press to the focus widget.
                                            Otherwise, it triggers the shortcut action, if one exists.
    \value Show                             Widget was shown on screen (QShowEvent).
    \value ShowToParent                     A child widget has been shown.
    \value SockAct                          Socket activated, used to implement QSocketNotifier.
    \omitvalue SockClose
    \value StateMachineSignal               A signal delivered to a state machine (QStateMachine::SignalEvent).
    \value StateMachineWrapped              The event is a wrapper for, i.e., contains, another event (QStateMachine::WrappedEvent).
    \value StatusTip                        A status tip is requested (QStatusTipEvent).
    \value StyleChange                      Widget's style has been changed.
    \value TabletMove                       Wacom tablet move (QTabletEvent).
    \value TabletPress                      Wacom tablet press (QTabletEvent).
    \value TabletRelease                    Wacom tablet release (QTabletEvent).
    \omitvalue OkRequest
    \value TabletEnterProximity             Wacom tablet enter proximity event (QTabletEvent), sent to QApplication.
    \value TabletLeaveProximity             Wacom tablet leave proximity event (QTabletEvent), sent to QApplication.
    \value [since 5.9] TabletTrackingChange The Wacom tablet tracking state has changed.
    \omitvalue ThemeChange
    \value ThreadChange                     The object is moved to another thread. This is the last event sent to this object in the previous thread. See QObject::moveToThread().
    \value Timer                            Regular timer events (QTimerEvent).
    \value ToolBarChange                    The toolbar button is toggled on \macos.
    \value ToolTip                          A tooltip was requested (QHelpEvent).
    \value ToolTipChange                    The widget's tooltip has changed.
    \value TouchBegin                       Beginning of a sequence of touch-screen or track-pad events (QTouchEvent).
    \value TouchCancel                      Cancellation of touch-event sequence (QTouchEvent).
    \value TouchEnd                         End of touch-event sequence (QTouchEvent).
    \value TouchUpdate                      Touch-screen event (QTouchEvent).
    \value UngrabKeyboard                   Item loses keyboard grab (QGraphicsItem only).
    \value UngrabMouse                      Item loses mouse grab (QGraphicsItem, QQuickItem).
    \value UpdateLater                      The widget should be queued to be repainted at a later time.
    \value UpdateRequest                    The widget should be repainted.
    \value WhatsThis                        The widget should reveal "What's This?" help (QHelpEvent).
    \value WhatsThisClicked                 A link in a widget's "What's This?" help was clicked.
    \value Wheel                            Mouse wheel rolled (QWheelEvent).
    \value WinEventAct                      A Windows-specific activation event has occurred.
    \value WindowActivate                   Window was activated.
    \value WindowBlocked                    The window is blocked by a modal dialog.
    \value WindowDeactivate                 Window was deactivated.
    \value WindowIconChange                 The window's icon has changed.
    \value WindowStateChange                The \l{QWindow::windowState()}{window's state} (minimized, maximized or full-screen) has changed (QWindowStateChangeEvent).
    \value WindowTitleChange                The window title has changed.
    \value WindowUnblocked                  The window is unblocked after a modal dialog exited.
    \value WinIdChange                      The window system identifier for this native widget has changed.
    \value ZOrderChange                     The widget's z-order has changed. This event is never sent to top level windows.
 
    User events should have values between \c User and \c{MaxUser}:
 
    \value User                             User-defined event.
    \value MaxUser                          Last user event ID.
 
    For convenience, you can use the registerEventType() function to
    register and reserve a custom event type for your
    application. Doing so will allow you to avoid accidentally
    re-using a custom event type already in use elsewhere in your
    application.
 
    \omitvalue AcceptDropsChange
    \omitvalue ActivateControl
    \omitvalue Create
    \omitvalue DeactivateControl
    \omitvalue Destroy
    \omitvalue DragResponse
    \omitvalue EmbeddingControl
    \omitvalue HelpRequest
    \omitvalue Quit
    \omitvalue ShowWindowRequest
    \omitvalue Speech
    \omitvalue Style
    \omitvalue StyleAnimationUpdate
    \omitvalue ZeroTimerEvent
    \omitvalue ApplicationActivate
    \omitvalue ApplicationActivated
    \omitvalue ApplicationDeactivate
    \omitvalue ApplicationDeactivated
    \omitvalue MacGLWindowChange
    \omitvalue NetworkReplyUpdated
    \omitvalue FutureCallOut
    \omitvalue NativeGesture
    \omitvalue WindowChangeInternal
    \omitvalue ScreenChangeInternal
    \omitvalue WindowAboutToChangeInternal
*/
 
/*!
    Constructs an event object of type \a type.
*/
QEvent::QEvent(Type type)
    : t(type), m_reserved(0),
      m_inputEvent(false), m_pointerEvent(false), m_singlePointEvent(false)
{
    Q_TRACE(QEvent_ctor, this, type);
}
 
/*!
    \fn QEvent::QEvent(const QEvent &other)
    \internal
    Copies the \a other event.
*/
 
/*!
    \internal
    \since 6.0
    \fn QEvent::QEvent(Type type, QEvent::InputEventTag)
 
    Constructs an event object of type \a type, setting the inputEvent flag to \c true.
*/
 
/*!
    \internal
    \since 6.0
    \fn QEvent::QEvent(Type type, QEvent::PointerEventTag)
 
    Constructs an event object of type \a type, setting the pointerEvent and
    inputEvent flags to \c true.
*/
 
/*!
    \internal
    \since 6.0
    \fn QEvent::QEvent(Type type, QEvent::SinglePointEventTag)
 
    Constructs an event object of type \a type, setting the singlePointEvent,
    pointerEvent and inputEvent flags to \c true.
*/
 
/*!
    \fn QEvent &QEvent::operator=(const QEvent &other)
    \internal
    Attempts to copy the \a other event.
 
    Copying events is a bad idea, yet some Qt 4 code does it (notably,
    QApplication and the state machine).
 */
 
/*!
    Destroys the event. If it was \l{QCoreApplication::postEvent()}{posted},
    it will be removed from the list of events to be posted.
*/
 
QEvent::~QEvent()
{
    if (m_posted && QCoreApplication::instance())
        QCoreApplicationPrivate::removePostedEvent(this);
}
 
/*!
    Creates and returns an identical copy of this event.
    \since 6.0
*/
QEvent *QEvent::clone() const
{ return new QEvent(*this); }
 
/*!
    \property  QEvent::accepted
    \brief the accept flag of the event object.
 
    Setting the accept parameter indicates that the event receiver
    wants the event. Unwanted events might be propagated to the parent
    widget. By default, isAccepted() is set to true, but don't rely on
    this as subclasses may choose to clear it in their constructor.
 
    For convenience, the accept flag can also be set with accept(),
    and cleared with ignore().
 
    \note Accepting a QPointerEvent implicitly
    \l {QEventPoint::setAccepted()}{accepts} all the
    \l {QPointerEvent::points()}{points} that the event carries.
*/
 
/*!
    \fn void QEvent::accept()
 
    Sets the accept flag of the event object, the equivalent of
    calling setAccepted(true).
 
    Setting the accept parameter indicates that the event receiver
    wants the event. Unwanted events might be propagated to the parent
    widget.
 
    \sa ignore()
*/
 
 
/*!
    \fn void QEvent::ignore()
 
    Clears the accept flag parameter of the event object, the
    equivalent of calling setAccepted(false).
 
    Clearing the accept parameter indicates that the event receiver
    does not want the event. Unwanted events might be propagated to the
    parent widget.
 
    \sa accept()
*/
 
 
/*!
    \fn QEvent::Type QEvent::type() const
 
    Returns the event type.
*/
 
/*!
    \fn bool QEvent::spontaneous() const
 
    Returns \c true if the event originated outside the application (a
    system event); otherwise returns \c false.
*/
 
/*!
    \fn bool QEvent::isInputEvent() const
    \since 6.0
 
    Returns \c true if the event object is a QInputEvent or one of its
    subclasses.
*/
 
/*!
    \fn bool QEvent::isPointerEvent() const
    \since 6.0
 
    Returns \c true if the event object is a QPointerEvent or one of its
    subclasses.
*/
 
/*!
    \fn bool QEvent::isSinglePointEvent() const
    \since 6.0
 
    Returns \c true if the event object is a subclass of QSinglePointEvent.
*/
 
namespace {
template <size_t N>
struct QBasicAtomicBitField {
    enum {
        BitsPerInt = std::numeric_limits<uint>::digits,
        NumInts = (N + BitsPerInt - 1) / BitsPerInt,
        NumBits = N
    };
 
    // This atomic int points to the next (possibly) free ID saving
    // the otherwise necessary scan through 'data':
    QBasicAtomicInteger<uint> next;
    QBasicAtomicInteger<uint> data[NumInts];
 
    constexpr QBasicAtomicBitField() = default;
 
    bool allocateSpecific(int which) noexcept
    {
        QBasicAtomicInteger<uint> &entry = data[which / BitsPerInt];
        const uint old = entry.loadRelaxed();
        const uint bit = 1U << (which % BitsPerInt);
        if (old & bit)
            return false;       // already taken
        return (entry.fetchAndOrRelaxed(bit) & bit) == 0;
 
        // don't update 'next' here - it's unlikely that it will need
        // to be updated, in the general case, and having 'next'
        // trailing a bit is not a problem, as it is just a starting
        // hint for allocateNext(), which, when wrong, will just
        // result in a few more rounds through the allocateNext()
        // loop.
    }
 
    int allocateNext() noexcept
    {
        // Unroll loop to iterate over ints, then bits? Would save
        // potentially a lot of cmpxchgs, because we can scan the
        // whole int before having to load it again.
 
        // Then again, this should never execute many iterations, so
        // leave like this for now:
        for (uint i = next.loadRelaxed(); i < NumBits; ++i) {
            if (allocateSpecific(i)) {
                // remember next (possibly) free id:
                const uint oldNext = next.loadRelaxed();
                next.testAndSetRelaxed(oldNext, qMax(i + 1, oldNext));
                return i;
            }
        }
        return -1;
    }
};
 
} // unnamed namespace
 
typedef QBasicAtomicBitField<QEvent::MaxUser - QEvent::User + 1> UserEventTypeRegistry;
 
Q_CONSTINIT static UserEventTypeRegistry userEventTypeRegistry {};
 
static inline int registerEventTypeZeroBased(int id) noexcept
{
    // if the type hint hasn't been registered yet, take it:
    if (id < UserEventTypeRegistry::NumBits && id >= 0 && userEventTypeRegistry.allocateSpecific(id))
        return id;
 
    // otherwise, ignore hint:
    return userEventTypeRegistry.allocateNext();
}
 
/*!
    \since 4.4
    \threadsafe
 
    Registers and returns a custom event type. The \a hint provided
    will be used if it is available, otherwise it will return a value
    between QEvent::User and QEvent::MaxUser that has not yet been
    registered. The \a hint is ignored if its value is not between
    QEvent::User and QEvent::MaxUser.
 
    Returns -1 if all available values are already taken or the
    program is shutting down.
*/
int QEvent::registerEventType(int hint) noexcept
{
    const int result = registerEventTypeZeroBased(QEvent::MaxUser - hint);
    return result < 0 ? -1 : QEvent::MaxUser - result ;
}
 
/*!
    \class QTimerEvent
    \inmodule QtCore
    \brief The QTimerEvent class contains parameters that describe a
    timer event.
 
    \ingroup events
 
    Timer events are sent at regular intervals to objects that have
    started one or more timers. Each timer has a unique identifier. A
    timer is started with QObject::startTimer().
 
    The QChronoTimer class provides a high-level programming interface that
    uses signals instead of events.
 
    The event handler QObject::timerEvent() receives timer events.
 
    \sa QChronoTimer, QObject::timerEvent(), QObject::startTimer(),
    QObject::killTimer()
*/
 
/*!
    Constructs a timer event object with the timer identifier set to
    \a timerId.
*/
QTimerEvent::QTimerEvent(int timerId)
    : QTimerEvent(Qt::TimerId{timerId})
{}
 
/*!
    \since 6.8
 
    Constructs a timer event object with the timer identifier set to
    \a timerId.
*/
QTimerEvent::QTimerEvent(Qt::TimerId timerId)
    : QEvent(Timer), m_id(timerId)
{
    static_assert(sizeof(Qt::TimerId) == sizeof(int));
}
 
Q_IMPL_EVENT_COMMON(QTimerEvent)
 
/*!
    \fn int QTimerEvent::timerId() const
 
    Returns the unique timer identifier, which is the same identifier
    as returned from QObject::startTimer().
*/
 
/*!
    \fn Qt::TimerId QTimerEvent::id() const
    \since 6.8
 
    Returns the Qt::TimerId of the timer associated with this event, which
    is the same identifier returned by QObject::startTimer() cast to
    Qt::TimerId.
*/
 
/*!
    \fn QTimerEvent::matches(const QBasicTimer &timer) const
    \since 6.9
 
    Returns \c true if this timer event and \a timer have the same ID,
    otherwise returns \c false.
*/
 
/*!
    \class QChildEvent
    \inmodule QtCore
    \brief The QChildEvent class contains event parameters for child object
    events.
 
    \ingroup events
 
    Child events are sent immediately to objects when children are
    added or removed.
 
    In both cases you can only rely on the child being a QObject (or,
    if QObject::isWidgetType() returns \c true, a QWidget). This is
    because in the QEvent::ChildAdded case the child is not yet fully
    constructed; in the QEvent::ChildRemoved case it might have
    already been destructed.
 
    The handler for these events is QObject::childEvent().
*/
 
/*!
    Constructs a child event object of a particular \a type for the
    \a child.
 
    \a type can be QEvent::ChildAdded, QEvent::ChildRemoved,
    or QEvent::ChildPolished.
 
    \sa child()
*/
QChildEvent::QChildEvent(Type type, QObject *child)
    : QEvent(type), c(child)
{}
 
Q_IMPL_EVENT_COMMON(QChildEvent)
 
/*!
    \fn QObject *QChildEvent::child() const
 
    Returns the child object that was added or removed.
*/
 
/*!
    \fn bool QChildEvent::added() const
 
    Returns \c true if type() is QEvent::ChildAdded; otherwise returns
    false.
*/
 
/*!
    \fn bool QChildEvent::removed() const
 
    Returns \c true if type() is QEvent::ChildRemoved; otherwise returns
    false.
*/
 
/*!
    \fn bool QChildEvent::polished() const
 
    Returns \c true if type() is QEvent::ChildPolished; otherwise returns
    false.
*/
 
 
/*!
    \class QDynamicPropertyChangeEvent
    \inmodule QtCore
    \since 4.2
    \brief The QDynamicPropertyChangeEvent class contains event parameters for dynamic
    property change events.
 
    \ingroup events
 
    Dynamic property change events are sent to objects when properties are
    dynamically added, changed or removed using QObject::setProperty().
*/
 
/*!
    Constructs a dynamic property change event object with the property name set to
    \a name.
*/
QDynamicPropertyChangeEvent::QDynamicPropertyChangeEvent(const QByteArray &name)
    : QEvent(QEvent::DynamicPropertyChange), n(name)
{
}
 
Q_IMPL_EVENT_COMMON(QDynamicPropertyChangeEvent)
 
/*!
    \fn QByteArray QDynamicPropertyChangeEvent::propertyName() const
 
    Returns the name of the dynamic property that was added, changed or
    removed.
 
    \sa QObject::setProperty(), QObject::dynamicPropertyNames()
*/
 
/*!
    Constructs a deferred delete event with the given loop and scope level.
*/
QDeferredDeleteEvent::QDeferredDeleteEvent(int loopLevel, int scopeLevel)
    : QEvent(QEvent::DeferredDelete), m_loopLevel(loopLevel), m_scopeLevel(scopeLevel)
{ }
 
Q_IMPL_EVENT_COMMON(QDeferredDeleteEvent)
 
QT_END_NAMESPACE
 
#include "moc_qcoreevent.cpp"