qobject.cpp

奇趣公司比较新的qt/emd版本

    and returns a list of those objects that are named or that match
    \a objName and inherit \a inheritsClass. If \a inheritsClass is 0
    (the default), all classes match. If \a objName is 0 (the
    default), all object names match.

    If \a regexpMatch is true (the default), \a objName is a regular
    expression that the objects's names must match. The syntax is that
    of a QRegExp. If \a regexpMatch is false, \a objName is a string
    and object names must match it exactly.

    Note that \a inheritsClass uses single inheritance from QObject,
    the way inherits() does. According to inherits(), QWidget
    inherits QObject but not QPaintDevice. This does not quite match
    reality, but is the best that can be done on the wide variety of
    compilers Qt supports.

    Finally, if \a recursiveSearch is true (the default), queryList()
    searches \e{n}th-generation as well as first-generation children.

    If all this seems a bit complex for your needs, the simpler
    child() function may be what you want.

    This somewhat contrived example disables all the buttons in this
    window:

    \code
        QList<QObject *> list = window()->queryList("QAbstractButton"));
        foreach (QObject *obj, list)
            static_cast<QAbstractButton *>(obj)->setEnabled(false);
    \endcode

    \warning Delete the list as soon you have finished using it. The
    list contains pointers that may become invalid at almost any time
    without notice (as soon as the user closes a window you may have
    dangling pointers, for example).

    \sa child() children(), parent(), inherits(), objectName(), QRegExp
*/

QObjectList QObject::queryList(const char *inheritsClass,
                                const char *objName,
                                bool regexpMatch,
                                bool recursiveSearch) const
{
    Q_D(const QObject);
    QObjectList list;
    bool onlyWidgets = (inheritsClass && qstrcmp(inheritsClass, "QWidget") == 0);
#ifndef QT_NO_REGEXP
    if (regexpMatch && objName) {                // regexp matching
        QRegExp rx(QString::fromLatin1(objName));
        objSearch(list, d->children, inheritsClass, onlyWidgets, 0, &rx, recursiveSearch);
    } else
#endif
    {
        objSearch(list, d->children, inheritsClass, onlyWidgets, objName, 0, recursiveSearch);
    }
    return list;
}
#endif

/*!
    \fn T *QObject::findChild(const QString &name) 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.

    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 \l{QPushButton} of \c{parentWidget}
    named \c{"button1"}:

    \code
        QPushButton *button = parentWidget->findChild<QPushButton *>("button1");
    \endcode

    This example returns a \l{QListWidget} child of \c{parentWidget}:

    \code
        QListWidget *list = parentWidget->findChild<QListWidget *>();
    \endcode

    \warning This function is not available with MSVC 6. Use
    qFindChild() instead if you need to support that version of the
    compiler.

    \sa findChildren(), qFindChild()
*/

/*!
    \fn QList<T> QObject::findChildren(const QString &name) 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.

    The following example shows how to find a list of child \l{QWidget}s of
    the specified \c{parentWidget} named \c{widgetname}:

    \code
        QList<QWidget *> widgets = parentWidget.findChildren<QWidget *>("widgetname");
    \endcode

    This example returns all \c{QPushButton}s that are children of \c{parentWidget}:

    \code
        QList<QPushButton *> allPButtons = parentWidget.findChildren<QPushButton *>();
    \endcode

    \warning This function is not available with MSVC 6. Use
    qFindChildren() instead if you need to support that version of the
    compiler.

    \sa findChild(), qFindChildren()
*/

/*!
    \fn QList<T> QObject::findChildren(const QRegExp &regExp) const
    \overload

    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.

    \warning This function is not available with MSVC 6. Use
    qFindChildren() instead if you need to support that version of the
    compiler.
*/

/*!
    \fn T qFindChild(const QObject *obj, const QString &name)
    \relates QObject

    This function is equivalent to
    \a{obj}->\l{QObject::findChild()}{findChild}<T>(\a name). It is
    provided as a work-around for MSVC 6, which doesn't support
    member template functions.

    \sa QObject::findChild()
*/

/*!
    \fn QList<T> qFindChildren(const QObject *obj, const QString &name)
    \relates QObject

    This function is equivalent to
    \a{obj}->\l{QObject::findChildren()}{findChildren}<T>(\a name). It is
    provided as a work-around for MSVC 6, which doesn't support
    member template functions.

    \sa QObject::findChildren()
*/

/*!
    \fn QList<T> qFindChildren(const QObject *obj, const QRegExp &regExp)
    \relates QObject
    \overload

    This function is equivalent to
    \a{obj}->\l{QObject::findChildren()}{findChildren}<T>(\a regExp). It is
    provided as a work-around for MSVC 6, which doesn't support
    member template functions.
*/

/*!
    \internal
    \fn T qFindChild(const QObject *obj, const QString &name = QString(), T dummy = 0)
    \relates QObject
    \overload

    This function is equivalent to
    \a{obj}->\l{QObject::findChild()}{findChild}<T>(\a name). It is
    provided as a work-around for MSVC 6, which doesn't support
    member template functions.

    \sa QObject::findChild()
*/

/*!
    \internal
    \fn QList<T> qFindChildren(const QObject *obj, const QString &name = QString(), T dummy = 0)
    \relates QObject
    \overload

    This function is equivalent to
    \a{obj}->\l{QObject::findChildren()}{findChildren}<T>(\a name). It is
    provided as a work-around for MSVC 6, which doesn't support
    member template functions.

    \sa QObject::findChildren()
*/

/*!
    \internal
*/
void qt_qFindChildren_helper(const QObject *parent, const QString &name, const QRegExp *re,
                         const QMetaObject &mo, QList<void*> *list)
{
    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 (re) {
                if (re->indexIn(obj->objectName()) != -1)
                    list->append(obj);
            } else {
                if (name.isNull() || obj->objectName() == name)
                    list->append(obj);
            }
        }
        qt_qFindChildren_helper(obj, name, re, mo, list);
    }
}

/*! \internal
 */
QObject *qt_qFindChild_helper(const QObject *parent, const QString &name, const QMetaObject &mo)
{
    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;
    }
    for (i = 0; i < children.size(); ++i) {
        obj = qt_qFindChild_helper(children.at(i), name, mo);
        if (obj)
            return obj;
    }
    return 0;
}

/*!
    Makes the object a child of \a parent.

    \sa QWidget::setParent()
*/

void QObject::setParent(QObject *parent)
{
    Q_D(QObject);
    Q_ASSERT(!d->isWidget);
    d->setParent_helper(parent);
}

void QObjectPrivate::deleteChildren()
{
    const bool reallyWasDeleted = wasDeleted;
    wasDeleted = 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;
    wasDeleted = reallyWasDeleted;
}

void QObjectPrivate::setParent_helper(QObject *o)
{
    Q_Q(QObject);
    if (o == parent)
        return;
    if (parent) {
        QObjectPrivate *parentD = parent->d_func();
        if (parentD->wasDeleted && 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->wasDeleted) {
                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);
#ifdef QT3_SUPPORT
                if (parent->d_func()->pendingChildInsertedEvents.isEmpty()) {
                    QCoreApplication::postEvent(parent,
                                                new QEvent(QEvent::ChildInsertedRequest),
                                                Qt::HighEventPriority);
                }
                parent->d_func()->pendingChildInsertedEvents.append(q);
#endif
            }
        }
    }
}

/*!
    \fn void QObject::installEventFilter(QObject *filterObj)
    \threadsafe

    Installs an event filter \a filterObj on this object. For example:
    \code
    monitoredObj->installEventFilter(filterObj);
    \endcode

    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:

    \code
        class KeyPressEater : public QObject
        {
            Q_OBJECT
            ...

        protected:
            bool eventFilter(QObject *obj, QEvent *event);
        };

        bool KeyPressEater::eventFilter(QObject *obj, QEvent *event)
        {
            if (event->type() == QEvent::KeyPress) {
                QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
                qDebug("Ate key press %d", keyEvent->key());
                return true;
            } else {
                // standard event processing
                return QObject::eventFilter(obj, event);
            }
        }
    \endcode

    And here's how to install it on two widgets:

    \code
        KeyPressEater *keyPressEater = new KeyPressEater(this);
        QPushButton *pushButton = new QPushButton(this);
        QListView *listView = new QListView(this);

        pushButton->installEventFilter(keyPressEater);
        listView->installEventFilter(keyPressEater);
    \endcode

    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.

    \sa removeEventFilter(), eventFilter(), event()
*/

void QObject::installEventFilter(QObject *obj)
{
    Q_D(QObject);
    if (!obj)
        return;

    QWriteLocker locker(QObjectPrivate::readWriteLock());

    // clean up unused items in the list
    d->eventFilters.removeAll((QObject*)0);
    d->eventFilters.removeAll(obj);
    d->eventFilters.prepend(obj);
}

/*!
    \threadsafe

    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
    t