lib/uilib/formbuilder.cpp

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#include "formbuilder.h"
#include "formbuilderextra_p.h"
#include "ui4_p.h"

#include <QtUiPlugin/customwidget.h>
#include <QtWidgets/QtWidgets>

QT_BEGIN_NAMESPACE

#ifdef QFORMINTERNAL_NAMESPACE
namespace QFormInternal {
#endif

/*!
    \class QFormBuilder

    \brief The QFormBuilder class is used to dynamically construct
    user interfaces from UI files at run-time.

    \inmodule QtDesigner

    The QFormBuilder class provides a mechanism for dynamically
    creating user interfaces at run-time, based on UI files
    created with \QD. For example:

    \snippet lib/tools_designer_src_lib_uilib_formbuilder.cpp 0

    By including the user interface in the example's resources (\c
    myForm.qrc), we ensure that it will be present when the example is
    run:

    \snippet lib/tools_designer_src_lib_uilib_formbuilder.cpp 1

    QFormBuilder extends the QAbstractFormBuilder base class with a
    number of functions that are used to support custom widget
    plugins:

    \list
    \li pluginPaths() returns the list of paths that the form builder
       searches when loading custom widget plugins.
    \li addPluginPath() allows additional paths to be registered with
       the form builder.
    \li setPluginPath() is used to replace the existing list of paths
       with a list obtained from some other source.
    \li clearPluginPaths() removes all paths registered with the form
       builder.
    \li customWidgets() returns a list of interfaces to plugins that
       can be used to create new instances of registered custom widgets.
    \endlist

    The QFormBuilder class is typically used by custom components and
    applications that embed \QD. Standalone applications that need to
    dynamically generate user interfaces at run-time use the
    QUiLoader class, found in the QtUiTools module.

    \sa QAbstractFormBuilder, {Qt UI Tools}
*/

/*!
    \fn QFormBuilder::QFormBuilder()

    Constructs a new form builder.
*/

QFormBuilder::QFormBuilder() = default;

/*!
    Destroys the form builder.
*/
QFormBuilder::~QFormBuilder() = default;

/*!
    \internal
*/
QWidget *QFormBuilder::create(DomWidget *ui_widget, QWidget *parentWidget)
{
    if (!d->parentWidgetIsSet())
        d->setParentWidget(parentWidget);
    // Is this a QLayoutWidget with a margin of 0: Not a known page-based
    // container and no method for adding pages registered.
    d->setProcessingLayoutWidget(false);
    if (ui_widget->attributeClass() == QFormBuilderStrings::instance().qWidgetClass && !ui_widget->hasAttributeNative()
            && parentWidget
#if QT_CONFIG(mainwindow)
            && !qobject_cast<QMainWindow *>(parentWidget)
#endif
#if QT_CONFIG(toolbox)
            && !qobject_cast<QToolBox *>(parentWidget)
#endif
#if QT_CONFIG(stackedwidget)
            && !qobject_cast<QStackedWidget *>(parentWidget)
#endif
#if QT_CONFIG(tabwidget)
            && !qobject_cast<QTabWidget *>(parentWidget)
#endif
#if QT_CONFIG(scrollarea)
            && !qobject_cast<QScrollArea *>(parentWidget)
#endif
#if QT_CONFIG(mdiarea)
            && !qobject_cast<QMdiArea *>(parentWidget)
#endif
#if QT_CONFIG(dockwidget)
            && !qobject_cast<QDockWidget *>(parentWidget)
#endif
        ) {
        const QString parentClassName = QLatin1String(parentWidget->metaObject()->className());
        if (!d->isCustomWidgetContainer(parentClassName))
            d->setProcessingLayoutWidget(true);
    }
    return QAbstractFormBuilder::create(ui_widget, parentWidget);
}


/*!
    \internal
*/
QWidget *QFormBuilder::createWidget(const QString &widgetName, QWidget *parentWidget, const QString &name)
{
    if (widgetName.isEmpty()) {
        //: Empty class name passed to widget factory method
        qWarning() << QCoreApplication::translate("QFormBuilder", "An empty class name was passed on to %1 (object name: '%2').").arg(QString::fromUtf8(Q_FUNC_INFO), name);
        return nullptr;
    }

    QWidget *w = nullptr;

#if QT_CONFIG(tabwidget)
    if (qobject_cast<QTabWidget*>(parentWidget))
        parentWidget = nullptr;
#endif
#if QT_CONFIG(stackedwidget)
    if (qobject_cast<QStackedWidget*>(parentWidget))
        parentWidget = nullptr;
#endif
#if QT_CONFIG(toolbox)
    if (qobject_cast<QToolBox*>(parentWidget))
        parentWidget = nullptr;
#endif

    // ### special-casing for Line (QFrame) -- fix for 4.2
    do {
        if (widgetName == QFormBuilderStrings::instance().lineClass) {
            w = new QFrame(parentWidget);
            static_cast<QFrame*>(w)->setFrameStyle(QFrame::HLine | QFrame::Sunken);
            break;
        }
        const QByteArray widgetNameBA = widgetName.toUtf8();
        const char *widgetNameC = widgetNameBA.constData();
        if (w) { // symmetry for macro
        }

#define DECLARE_LAYOUT(L, C)
#define DECLARE_COMPAT_WIDGET(W, C)
#define DECLARE_WIDGET(W, C) else if (!qstrcmp(widgetNameC, #W)) { Q_ASSERT(w == 0); w = new W(parentWidget); }
#define DECLARE_WIDGET_1(W, C) else if (!qstrcmp(widgetNameC, #W)) { Q_ASSERT(w == 0); w = new W(0, parentWidget); }

#include "widgets.table"

#undef DECLARE_COMPAT_WIDGET
#undef DECLARE_LAYOUT
#undef DECLARE_WIDGET
#undef DECLARE_WIDGET_1

        if (w)
            break;

        // try with a registered custom widget
        QDesignerCustomWidgetInterface *factory = d->m_customWidgets.value(widgetName);
        if (factory != nullptr)
            w = factory->createWidget(parentWidget);
    } while(false);

    if (w == nullptr) { // Attempt to instantiate base class of promoted/custom widgets
        const QString baseClassName = d->customWidgetBaseClass(widgetName);
        if (!baseClassName.isEmpty()) {
            qWarning() << QCoreApplication::translate("QFormBuilder", "QFormBuilder was unable to create a custom widget of the class '%1'; defaulting to base class '%2'.").arg(widgetName, baseClassName);
            return createWidget(baseClassName, parentWidget, name);
        }
    }

    if (w == nullptr) { // nothing to do
        qWarning() << QCoreApplication::translate("QFormBuilder", "QFormBuilder was unable to create a widget of the class '%1'.").arg(widgetName);
        return nullptr;
    }

    w->setObjectName(name);

    if (qobject_cast<QDialog *>(w))
        w->setParent(parentWidget);

    return w;
}

/*!
    \internal
*/
QLayout *QFormBuilder::createLayout(const QString &layoutName, QObject *parent, const QString &name)
{
    QLayout *l = nullptr;

    QWidget *parentWidget = qobject_cast<QWidget*>(parent);
    QLayout *parentLayout = qobject_cast<QLayout*>(parent);

    Q_ASSERT(parentWidget || parentLayout);

#define DECLARE_WIDGET(W, C)
#define DECLARE_COMPAT_WIDGET(W, C)

#define DECLARE_LAYOUT(L, C) \
    if (layoutName == QLatin1String(#L)) { \
        Q_ASSERT(l == 0); \
        l = parentLayout \
            ? new L() \
            : new L(parentWidget); \
    }

#include "widgets.table"

#undef DECLARE_LAYOUT
#undef DECLARE_COMPAT_WIDGET
#undef DECLARE_WIDGET

    if (l) {
        l->setObjectName(name);
    } else {
        qWarning() << QCoreApplication::translate("QFormBuilder", "The layout type `%1' is not supported.").arg(layoutName);
    }

    return l;
}

/*!
    \internal
*/
bool QFormBuilder::addItem(DomLayoutItem *ui_item, QLayoutItem *item, QLayout *layout)
{
    return QAbstractFormBuilder::addItem(ui_item, item, layout);
}

/*!
    \internal
*/
bool QFormBuilder::addItem(DomWidget *ui_widget, QWidget *widget, QWidget *parentWidget)
{
    return QAbstractFormBuilder::addItem(ui_widget, widget, parentWidget);
}

/*!
    \internal
*/
QWidget *QFormBuilder::widgetByName(QWidget *topLevel, const QString &name)
{
    Q_ASSERT(topLevel);
    if (topLevel->objectName() == name)
        return topLevel;

    return topLevel->findChild<QWidget*>(name);
}

static QObject *objectByName(QWidget *topLevel, const QString &name)
{
    Q_ASSERT(topLevel);
    if (topLevel->objectName() == name)
        return topLevel;

    return topLevel->findChild<QObject*>(name);
}

/*!
    \internal
*/
void QFormBuilder::createConnections(DomConnections *ui_connections, QWidget *widget)
{
    Q_ASSERT(widget != nullptr);

    if (ui_connections == nullptr)
        return;

    const auto &connections = ui_connections->elementConnection();
    for (const DomConnection *c : connections) {
        QObject *sender = objectByName(widget, c->elementSender());
        QObject *receiver = objectByName(widget, c->elementReceiver());
        if (!sender || !receiver)
            continue;

        QByteArray sig = c->elementSignal().toUtf8();
        sig.prepend("2");
        QByteArray sl = c->elementSlot().toUtf8();
        sl.prepend("1");
        QObject::connect(sender, sig, receiver, sl);
    }
}

/*!
    \internal
*/
QWidget *QFormBuilder::create(DomUI *ui, QWidget *parentWidget)
{
    return QAbstractFormBuilder::create(ui, parentWidget);
}

/*!
    \internal
*/
QLayout *QFormBuilder::create(DomLayout *ui_layout, QLayout *layout, QWidget *parentWidget)
{
    // Is this a temporary layout widget used to represent QLayout hierarchies in Designer?
    // Set its margins to 0.
    bool layoutWidget = d->processingLayoutWidget();
    QLayout *l = QAbstractFormBuilder::create(ui_layout, layout, parentWidget);
    if (layoutWidget) {
        const QFormBuilderStrings &strings = QFormBuilderStrings::instance();
        int left, top, right, bottom;
        left = top = right = bottom = 0;
        const DomPropertyHash properties = propertyMap(ui_layout->elementProperty());

        if (DomProperty *prop = properties.value(strings.leftMarginProperty))
            left = prop->elementNumber();

        if (DomProperty *prop = properties.value(strings.topMarginProperty))
            top = prop->elementNumber();

        if (DomProperty *prop = properties.value(strings.rightMarginProperty))
            right = prop->elementNumber();

        if (DomProperty *prop = properties.value(strings.bottomMarginProperty))
            bottom = prop->elementNumber();

        l->setContentsMargins(left, top, right, bottom);
        d->setProcessingLayoutWidget(false);
    }
    return l;
}

/*!
    \internal
*/
QLayoutItem *QFormBuilder::create(DomLayoutItem *ui_layoutItem, QLayout *layout, QWidget *parentWidget)
{
    return QAbstractFormBuilder::create(ui_layoutItem, layout, parentWidget);
}

/*!
    \internal
*/
QAction *QFormBuilder::create(DomAction *ui_action, QObject *parent)
{
    return QAbstractFormBuilder::create(ui_action, parent);
}

/*!
    \internal
*/
QActionGroup *QFormBuilder::create(DomActionGroup *ui_action_group, QObject *parent)
{
    return QAbstractFormBuilder::create(ui_action_group, parent);
}

/*!
    Returns the list of paths the form builder searches for plugins.

    \sa addPluginPath()
*/
QStringList QFormBuilder::pluginPaths() const
{
    return d->m_pluginPaths;
}

/*!
    Clears the list of paths that the form builder uses to search for
    custom widget plugins.

    \sa pluginPaths()
*/
void QFormBuilder::clearPluginPaths()
{
    d->m_pluginPaths.clear();
    updateCustomWidgets();
}

/*!
    Adds a new plugin path specified by \a pluginPath to the list of
    paths that will be searched by the form builder when loading a
    custom widget plugin.

    \sa setPluginPath(), clearPluginPaths()
*/
void QFormBuilder::addPluginPath(const QString &pluginPath)
{
    d->m_pluginPaths.append(pluginPath);
    updateCustomWidgets();
}

/*!
    Sets the list of plugin paths to the list specified by \a pluginPaths.

    \sa addPluginPath()
*/
void QFormBuilder::setPluginPath(const QStringList &pluginPaths)
{
    d->m_pluginPaths = pluginPaths;
    updateCustomWidgets();
}

static void insertPlugins(QObject *o, QMap<QString, QDesignerCustomWidgetInterface*> *customWidgets)
{
    // step 1) try with a normal plugin
    if (QDesignerCustomWidgetInterface *iface = qobject_cast<QDesignerCustomWidgetInterface *>(o)) {
        customWidgets->insert(iface->name(), iface);
        return;
    }
    // step 2) try with a collection of plugins
    if (QDesignerCustomWidgetCollectionInterface *c = qobject_cast<QDesignerCustomWidgetCollectionInterface *>(o)) {
        const auto &collectionCustomWidgets = c->customWidgets();
        for (QDesignerCustomWidgetInterface *iface : collectionCustomWidgets)
            customWidgets->insert(iface->name(), iface);
    }
}

/*!
    \internal
*/
void QFormBuilder::updateCustomWidgets()
{
    d->m_customWidgets.clear();

#if QT_CONFIG(library)
    for (const QString &path : qAsConst(d->m_pluginPaths)) {
        const QDir dir(path);
        const QStringList candidates = dir.entryList(QDir::Files);

        for (const QString &plugin : candidates) {
            if (!QLibrary::isLibrary(plugin))
                continue;

            QString loaderPath = path;
            loaderPath += QLatin1Char('/');
            loaderPath += plugin;

            QPluginLoader loader(loaderPath);
            if (loader.load())
                insertPlugins(loader.instance(), &d->m_customWidgets);
        }
    }
#endif // QT_CONFIG(library)

    // Check statically linked plugins
    const QObjectList staticPlugins = QPluginLoader::staticInstances();
    for (QObject *o : staticPlugins)
        insertPlugins(o, &d->m_customWidgets);
}

/*!
    \fn QList<QDesignerCustomWidgetInterface*> QFormBuilder::customWidgets() const

    Returns a list of the available plugins.
*/
QList<QDesignerCustomWidgetInterface*> QFormBuilder::customWidgets() const
{
    return d->m_customWidgets.values();
}

/*!
    \internal
*/

void QFormBuilder::applyProperties(QObject *o, const QList<DomProperty*> &properties)
{

    if (properties.isEmpty())
        return;

    const QFormBuilderStrings &strings = QFormBuilderStrings::instance();

    for (DomProperty *p : properties) {
        const QVariant v = toVariant(o->metaObject(), p);
        if (!v.isValid()) // QTBUG-33130, do not fall for QVariant(QString()).isNull() == true.
            continue;

        const QString attributeName = p->attributeName();
        const bool isWidget = o->isWidgetType();
        if (isWidget && o->parent() == d->parentWidget() && attributeName == strings.geometryProperty) {
            // apply only the size part of a geometry for the root widget
            static_cast<QWidget*>(o)->resize(qvariant_cast<QRect>(v).size());
        } else if (d->applyPropertyInternally(o, attributeName, v)) {
        } else if (isWidget && !qstrcmp("QFrame", o->metaObject()->className ()) && attributeName == strings.orientationProperty) {
            // ### special-casing for Line (QFrame) -- try to fix me
            o->setProperty("frameShape", v); // v is of QFrame::Shape enum
        } else {
            o->setProperty(attributeName.toUtf8(), v);
        }
    }
}

#ifdef QFORMINTERNAL_NAMESPACE
} // namespace QFormInternal
#endif

QT_END_NAMESPACE