quiloader.cpp

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// Copyright (C) 2020 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
 
#include "quiloader.h"
#include "quiloader_p.h"
 
#include <QtUiPlugin/customwidget.h>
 
#include <formbuilder.h>
#include <formbuilderextra_p.h>
#include <textbuilder_p.h>
#include <ui4_p.h>
 
#include <QtWidgets/qapplication.h>
#include <QtWidgets/qlayout.h>
#include <QtWidgets/qwidget.h>
#if QT_CONFIG(tabwidget)
#   include <QtWidgets/qtabwidget.h>
#endif
#if QT_CONFIG(treewidget)
#  include <QtWidgets/qtreewidget.h>
#endif
#if QT_CONFIG(listwidget)
#   include <QtWidgets/qlistwidget.h>
#endif
#if QT_CONFIG(tablewidget)
#  include <QtWidgets/qtablewidget.h>
#endif
#if QT_CONFIG(toolbox)
#  include <QtWidgets/qtoolbox.h>
#endif
#if QT_CONFIG(combobox)
#  include <QtWidgets/qcombobox.h>
#endif
 
#include <QtGui/qaction.h>
#include <QtGui/qactiongroup.h>
 
#include <QtCore/qdebug.h>
#include <QtCore/qdatastream.h>
#include <QtCore/qmap.h>
#include <QtCore/qdir.h>
#include <QtCore/qlibraryinfo.h>
 
#include <algorithm>
 
QT_BEGIN_NAMESPACE
 
using widget_map = QMap<QString, bool>;
Q_GLOBAL_STATIC(widget_map, g_widgets)
 
class QUiLoader;
class QUiLoaderPrivate;
 
#ifndef QT_NO_DATASTREAM
// QUiTranslatableStringValue must be streamable since they become part of the QVariant-based
// mime data when dragging items in views with QAbstractItemView::InternalMove.
QDataStream &operator<<(QDataStream &out, const QUiTranslatableStringValue &s)
{
    out << s.qualifier() << s.value();
    return out;
}
 
QDataStream &operator>>(QDataStream &in, QUiTranslatableStringValue &s)
{
    QByteArray qualifier, value;
    in >> qualifier >> value;
    s.setQualifier(qualifier);
    s.setValue(value);
    return in;
}
#endif // QT_NO_DATASTREAM
 
QString QUiTranslatableStringValue::translate(const QByteArray &className, bool idBased) const
{
    return idBased
        ? qtTrId(m_qualifier.constData())
        : QCoreApplication::translate(className.constData(), m_value.constData(), m_qualifier.constData());
}
 
#ifdef QFORMINTERNAL_NAMESPACE
namespace QFormInternal
{
#endif
 
class TranslatingTextBuilder : public QTextBuilder
{
public:
    explicit TranslatingTextBuilder(bool idBased, bool trEnabled, const QByteArray &className) :
        m_idBased(idBased), m_trEnabled(trEnabled), m_className(className) {}
 
    QVariant loadText(const DomProperty *icon) const override;
 
    QVariant toNativeValue(const QVariant &value) const override;
 
    bool idBased() const { return m_idBased; }
 
private:
    bool m_idBased;
    bool m_trEnabled;
    QByteArray m_className;
};
 
QVariant TranslatingTextBuilder::loadText(const DomProperty *text) const
{
    const DomString *str = text->elementString();
    if (!str)
        return {};
    if (str->hasAttributeNotr()) {
        const QString notr = str->attributeNotr();
        if (notr == QStringLiteral("true") || notr == QStringLiteral("yes"))
            return QVariant::fromValue(str->text());
    }
    QUiTranslatableStringValue strVal;
    strVal.setValue(str->text().toUtf8());
    if (m_idBased)
        strVal.setQualifier(str->attributeId().toUtf8());
    else if (str->hasAttributeComment())
        strVal.setQualifier(str->attributeComment().toUtf8());
    return QVariant::fromValue(strVal);
}
 
QVariant TranslatingTextBuilder::toNativeValue(const QVariant &value) const
{
    if (value.canConvert<QUiTranslatableStringValue>()) {
        auto tsv = qvariant_cast<QUiTranslatableStringValue>(value);
        if (!m_trEnabled)
            return QString::fromUtf8(tsv.value().constData());
        return QVariant::fromValue(tsv.translate(m_className, m_idBased));
    }
    if (value.canConvert<QString>())
        return QVariant::fromValue(qvariant_cast<QString>(value));
    return value;
}
 
// This is "exported" to linguist
const QUiItemRolePair qUiItemRoles[] = {
    { Qt::DisplayRole, Qt::DisplayPropertyRole },
#if QT_CONFIG(tooltip)
    { Qt::ToolTipRole, Qt::ToolTipPropertyRole },
#endif
#if QT_CONFIG(statustip)
    { Qt::StatusTipRole, Qt::StatusTipPropertyRole },
#endif
#if QT_CONFIG(whatsthis)
    { Qt::WhatsThisRole, Qt::WhatsThisPropertyRole },
#endif
    { -1 , -1 }
};
 
#if QT_CONFIG(treewidget)
static void recursiveReTranslate(QTreeWidgetItem *item, const QByteArray &class_name, bool idBased)
{
    const QUiItemRolePair *irs = qUiItemRoles;
 
    int cnt = item->columnCount();
    for (int i = 0; i < cnt; ++i) {
        for (unsigned j = 0; irs[j].shadowRole >= 0; j++) {
            QVariant v = item->data(i, irs[j].shadowRole);
            if (v.isValid()) {
                auto tsv = qvariant_cast<QUiTranslatableStringValue>(v);
                item->setData(i, irs[j].realRole, tsv.translate(class_name, idBased));
            }
        }
    }
 
    cnt = item->childCount();
    for (int i = 0; i < cnt; ++i)
        recursiveReTranslate(item->child(i), class_name, idBased);
}
#endif
 
template<typename T>
static void reTranslateWidgetItem(T *item, const QByteArray &class_name, bool idBased)
{
    const QUiItemRolePair *irs = qUiItemRoles;
 
    for (unsigned j = 0; irs[j].shadowRole >= 0; j++) {
        QVariant v = item->data(irs[j].shadowRole);
        if (v.isValid()) {
            auto tsv = qvariant_cast<QUiTranslatableStringValue>(v);
            item->setData(irs[j].realRole, tsv.translate(class_name, idBased));
        }
    }
}
 
#if QT_CONFIG(tablewidget)
static void reTranslateTableItem(QTableWidgetItem *item, const QByteArray &class_name, bool idBased)
{
    if (item)
        reTranslateWidgetItem(item, class_name, idBased);
}
#endif
 
class TranslationWatcher: public QObject
{
    Q_OBJECT
 
public:
    explicit TranslationWatcher(QObject *parent, const QByteArray &className, bool idBased):
        QObject(parent),
        m_className(className),
        m_idBased(idBased)
    {
    }
 
    bool eventFilter(QObject *o, QEvent *event) override
    {
        if (event->type() == QEvent::LanguageChange) {
            const auto &dynamicPropertyNames = o->dynamicPropertyNames();
            for (const QByteArray &prop : dynamicPropertyNames) {
                if (prop.startsWith(PROP_GENERIC_PREFIX)) {
                    const QByteArray propName = prop.mid(sizeof(PROP_GENERIC_PREFIX) - 1);
                    const auto tsv =
                                qvariant_cast<QUiTranslatableStringValue>(o->property(prop.constData()));
                    o->setProperty(propName.constData(), tsv.translate(m_className, m_idBased));
                }
            }
            if (0) {
#if QT_CONFIG(tabwidget)
            } else if (auto *tabw = qobject_cast<QTabWidget*>(o)) {
                const int cnt = tabw->count();
                for (int i = 0; i < cnt; ++i) {
                    retranslateSubwidgetProperty(tabw, &QTabWidget::setTabText, i, PROP_TABPAGETEXT);
#if QT_CONFIG(tooltip)
                    retranslateSubwidgetProperty(tabw, &QTabWidget::setTabToolTip, i, PROP_TABPAGETOOLTIP);
# endif
#if QT_CONFIG(whatsthis)
                    retranslateSubwidgetProperty(tabw, &QTabWidget::setTabWhatsThis, i, PROP_TABPAGEWHATSTHIS);
# endif
                }
#endif
#if QT_CONFIG(listwidget)
            } else if (auto *listw = qobject_cast<QListWidget*>(o)) {
                const int cnt = listw->count();
                for (int i = 0; i < cnt; ++i)
                    reTranslateWidgetItem(listw->item(i), m_className, m_idBased);
#endif
#if QT_CONFIG(treewidget)
            } else if (auto *treew = qobject_cast<QTreeWidget*>(o)) {
                if (QTreeWidgetItem *item = treew->headerItem())
                    recursiveReTranslate(item, m_className, m_idBased);
                const int cnt = treew->topLevelItemCount();
                for (int i = 0; i < cnt; ++i) {
                    QTreeWidgetItem *item = treew->topLevelItem(i);
                    recursiveReTranslate(item, m_className, m_idBased);
                }
#endif
#if QT_CONFIG(tablewidget)
            } else if (auto *tablew = qobject_cast<QTableWidget*>(o)) {
                const int row_cnt = tablew->rowCount();
                const int col_cnt = tablew->columnCount();
                for (int j = 0; j < col_cnt; ++j)
                    reTranslateTableItem(tablew->horizontalHeaderItem(j), m_className, m_idBased);
                for (int i = 0; i < row_cnt; ++i) {
                    reTranslateTableItem(tablew->verticalHeaderItem(i), m_className, m_idBased);
                    for (int j = 0; j < col_cnt; ++j)
                        reTranslateTableItem(tablew->item(i, j), m_className, m_idBased);
                }
#endif
#if QT_CONFIG(combobox)
            } else if (auto *combow = qobject_cast<QComboBox*>(o)) {
                if (!QFormBuilderExtra::isQFontComboBox(combow)) {
                    const int cnt = combow->count();
                    for (int i = 0; i < cnt; ++i) {
                        const QVariant v = combow->itemData(i, Qt::DisplayPropertyRole);
                        if (v.isValid()) {
                            auto tsv = qvariant_cast<QUiTranslatableStringValue>(v);
                            combow->setItemText(i, tsv.translate(m_className, m_idBased));
                        }
                    }
                }
#endif
#if QT_CONFIG(toolbox)
            } else if (auto *toolw = qobject_cast<QToolBox*>(o)) {
                const int cnt = toolw->count();
                for (int i = 0; i < cnt; ++i) {
                    retranslateSubwidgetProperty(toolw, &QToolBox::setItemText, i, PROP_TOOLITEMTEXT);
#if QT_CONFIG(tooltip)
                    retranslateSubwidgetProperty(toolw, &QToolBox::setItemToolTip, i, PROP_TOOLITEMTOOLTIP);
# endif
                }
#endif
            }
        }
        return false;
    }
 
    template <class Widget>
    void retranslateSubwidgetProperty(Widget *mainWidget,
                                      void (Widget::*setter)(int, const QString &),
                                      int i,
                                      const char *propName) const
    {
        QVariant v = mainWidget->widget(i)->property(propName);
        if (v.isValid()) {
            const auto tsv = qvariant_cast<QUiTranslatableStringValue>(v);
            (mainWidget->*setter)(i, tsv.translate(m_className, m_idBased));
        }
    }
 
private:
    QByteArray m_className;
    bool m_idBased;
};
 
class FormBuilderPrivate: public QFormBuilder
{
    friend class QT_PREPEND_NAMESPACE(QUiLoader);
    friend class QT_PREPEND_NAMESPACE(QUiLoaderPrivate);
    using ParentClass = QFormBuilder;
 
public:
    QUiLoader *loader = nullptr;
 
    bool dynamicTr = false;
    bool trEnabled = true;
 
    FormBuilderPrivate() = default;
 
    QWidget *defaultCreateWidget(const QString &className, QWidget *parent, const QString &name)
    {
        return ParentClass::createWidget(className, parent, name);
    }
 
    QLayout *defaultCreateLayout(const QString &className, QObject *parent, const QString &name)
    {
        return ParentClass::createLayout(className, parent, name);
    }
 
    QAction *defaultCreateAction(QObject *parent, const QString &name)
    {
        return ParentClass::createAction(parent, name);
    }
 
    QActionGroup *defaultCreateActionGroup(QObject *parent, const QString &name)
    {
        return ParentClass::createActionGroup(parent, name);
    }
 
    QWidget *createWidget(const QString &className, QWidget *parent, const QString &name) override
    {
        if (QWidget *widget = loader->createWidget(className, parent, name)) {
            widget->setObjectName(name);
            return widget;
        }
 
        return nullptr;
    }
 
    QLayout *createLayout(const QString &className, QObject *parent, const QString &name) override
    {
        if (QLayout *layout = loader->createLayout(className, parent, name)) {
            layout->setObjectName(name);
            return layout;
        }
 
        return nullptr;
    }
 
    QActionGroup *createActionGroup(QObject *parent, const QString &name) override
    {
        if (QActionGroup *actionGroup = loader->createActionGroup(parent, name)) {
            actionGroup->setObjectName(name);
            return actionGroup;
        }
 
        return nullptr;
    }
 
    QAction *createAction(QObject *parent, const QString &name)  override
    {
        if (QAction *action = loader->createAction(parent, name)) {
            action->setObjectName(name);
            return action;
        }
 
        return nullptr;
    }
 
    void applyProperties(QObject *o, const QList<DomProperty*> &properties) override;
    QWidget *create(DomUI *ui, QWidget *parentWidget) override;
    QWidget *create(DomWidget *ui_widget, QWidget *parentWidget) override;
    bool addItem(DomWidget *ui_widget, QWidget *widget, QWidget *parentWidget) override;
 
    template <class Widget>
    void translateSubwidgetProperty(const QList<DomProperty*> &attributes,
                                    Widget *mainWidget,
                                    const QString &attribute,
                                    int i,
                                    void (Widget::*setter)(int, const QString &),
                                    const char *propName) const;
 
private:
    QByteArray m_class;
    TranslationWatcher *m_trwatch = nullptr;
    bool m_idBased = false;
};
 
static QString convertTranslatable(const DomProperty *p, const QByteArray &className,
                                   bool idBased, QUiTranslatableStringValue *strVal)
{
    if (p->kind() != DomProperty::String)
        return {};
    const DomString *dom_str = p->elementString();
    if (!dom_str)
        return {};
    if (dom_str->hasAttributeNotr()) {
        const QString notr = dom_str->attributeNotr();
        if (notr == QStringLiteral("yes") || notr == QStringLiteral("true"))
            return {};
    }
    strVal->setValue(dom_str->text().toUtf8());
    strVal->setQualifier(idBased ? dom_str->attributeId().toUtf8() : dom_str->attributeComment().toUtf8());
    if (strVal->value().isEmpty() && strVal->qualifier().isEmpty())
        return {};
    return strVal->translate(className, idBased);
}
 
static DomProperty *attributeByName(const QList<DomProperty*> &attributes,
                                    const QString &attribute)
{
    auto pred = [&attribute](const DomProperty *prop) {
        return prop->attributeName() == attribute;
    };
    auto it = std::find_if(attributes.cbegin(), attributes.cend(), pred);
    return it != attributes.cend() ? *it : nullptr;
}
 
template <class Widget>
void FormBuilderPrivate::translateSubwidgetProperty(const QList<DomProperty*> &attributes,
                                                    Widget *mainWidget,
                                                    const QString &attribute,
                                                    int i,
                                                    void (Widget::*setter)(int, const QString &),
                                                    const char *propName) const
{
    if (const auto *p = attributeByName(attributes, attribute)) {
        QUiTranslatableStringValue strVal;
        const QString text = convertTranslatable(p, m_class, m_idBased, &strVal);
        if (!text.isEmpty()) {
            if (dynamicTr)
                mainWidget->widget(i)->setProperty(propName, QVariant::fromValue(strVal));
            (mainWidget->*setter)(i, text);
        }
    }
}
 
void FormBuilderPrivate::applyProperties(QObject *o, const QList<DomProperty*> &properties)
{
    QFormBuilder::applyProperties(o, properties);
 
    if (!m_trwatch)
        m_trwatch = new TranslationWatcher(o, m_class, m_idBased);
 
    if (properties.isEmpty())
        return;
 
    // Unlike string item roles, string properties are not loaded via the textBuilder
    // (as they are "shadowed" by the property sheets in designer). So do the initial
    // translation here.
    bool anyTrs = false;
    for (const DomProperty *p : properties) {
        QUiTranslatableStringValue strVal;
        const QString text = convertTranslatable(p, m_class, m_idBased, &strVal);
        if (text.isEmpty())
            continue;
        const QByteArray name = p->attributeName().toUtf8();
        if (dynamicTr) {
            const QByteArray dynname = QByteArray(PROP_GENERIC_PREFIX + name);
            o->setProperty(dynname.constData(), QVariant::fromValue(strVal));
            anyTrs = trEnabled;
        }
        if (p->elementString()->text() != text)
            o->setProperty(name.constData(), text);
    }
    if (anyTrs)
        o->installEventFilter(m_trwatch);
}
 
QWidget *FormBuilderPrivate::create(DomUI *ui, QWidget *parentWidget)
{
    m_class = ui->elementClass().toUtf8();
    m_trwatch = nullptr;
    m_idBased = ui->attributeIdbasedtr();
    setTextBuilder(new TranslatingTextBuilder(m_idBased, trEnabled, m_class));
    return QFormBuilder::create(ui, parentWidget);
}
 
QWidget *FormBuilderPrivate::create(DomWidget *ui_widget, QWidget *parentWidget)
{
    QWidget *w = QFormBuilder::create(ui_widget, parentWidget);
    if (w == nullptr)
        return nullptr;
 
    if (0) {
#if QT_CONFIG(tabwidget)
    } else if (qobject_cast<QTabWidget*>(w)) {
#endif
#if QT_CONFIG(listwidget)
    } else if (qobject_cast<QListWidget*>(w)) {
#endif
#if QT_CONFIG(treewidget)
    } else if (qobject_cast<QTreeWidget*>(w)) {
#endif
#if QT_CONFIG(tablewidget)
    } else if (qobject_cast<QTableWidget*>(w)) {
#endif
#if QT_CONFIG(combobox)
    } else if (qobject_cast<QComboBox*>(w)) {
        if (QFormBuilderExtra::isQFontComboBox(w))
            return w;
#endif
#if QT_CONFIG(toolbox)
    } else if (qobject_cast<QToolBox*>(w)) {
#endif
    } else {
        return w;
    }
    if (dynamicTr && trEnabled)
        w->installEventFilter(m_trwatch);
    return w;
}
 
bool FormBuilderPrivate::addItem(DomWidget *ui_widget, QWidget *widget, QWidget *parentWidget)
{
    if (parentWidget == nullptr)
        return true;
 
    if (!ParentClass::addItem(ui_widget, widget, parentWidget))
        return false;
 
    // Check special cases. First: Custom container
    const QString className = QLatin1String(parentWidget->metaObject()->className());
    if (!d->customWidgetAddPageMethod(className).isEmpty())
        return true;
 
    if (0) {
#if QT_CONFIG(tabwidget)
    } else if (auto *tabWidget = qobject_cast<QTabWidget*>(parentWidget)) {
        const int i = tabWidget->count() - 1;
        translateSubwidgetProperty(ui_widget->elementAttribute(), tabWidget,
                                   QFormBuilderStrings::titleAttribute,
                                   i, &QTabWidget::setTabText, PROP_TABPAGETEXT);
#if QT_CONFIG(tooltip)
        translateSubwidgetProperty(ui_widget->elementAttribute(), tabWidget,
                                   QFormBuilderStrings::toolTipAttribute,
                                   i, &QTabWidget::setTabToolTip, PROP_TABPAGETOOLTIP);
# endif
#if QT_CONFIG(whatsthis)
        translateSubwidgetProperty(ui_widget->elementAttribute(), tabWidget,
                                   QFormBuilderStrings::whatsThisAttribute,
                                   i, &QTabWidget::setTabWhatsThis, PROP_TABPAGEWHATSTHIS);
# endif
#endif
#if QT_CONFIG(toolbox)
    } else if (auto *toolBox = qobject_cast<QToolBox*>(parentWidget)) {
        const int i = toolBox->count() - 1;
        translateSubwidgetProperty(ui_widget->elementAttribute(), toolBox,
                                   QFormBuilderStrings::labelAttribute,
                                   i, &QToolBox::setItemText, PROP_TOOLITEMTEXT);
#if QT_CONFIG(tooltip)
        translateSubwidgetProperty(ui_widget->elementAttribute(), toolBox,
                                   QFormBuilderStrings::toolTipAttribute,
                                   i, &QToolBox::setItemToolTip, PROP_TOOLITEMTOOLTIP);
# endif
#endif
    }
 
    return true;
}
 
#ifdef QFORMINTERNAL_NAMESPACE
}
#endif
 
class QUiLoaderPrivate
{
public:
#ifdef QFORMINTERNAL_NAMESPACE
    QFormInternal::FormBuilderPrivate builder;
#else
    FormBuilderPrivate builder;
#endif
 
    void setupWidgetMap() const;
};
 
void QUiLoaderPrivate::setupWidgetMap() const
{
    if (!g_widgets()->isEmpty())
        return;
 
#define DECLARE_WIDGET(a, b) g_widgets()->insert(QLatin1String(#a), true);
#define DECLARE_LAYOUT(a, b)
 
#include "widgets.table"
 
#undef DECLARE_WIDGET
#undef DECLARE_WIDGET_1
#undef DECLARE_LAYOUT
}
 
/*!
    \class QUiLoader
    \inmodule QtUiTools
 
    \brief The QUiLoader class enables standalone applications to
    dynamically create user interfaces at run-time using the
    information stored in UI files or specified in plugin paths.
 
    In addition, you can customize or create your own user interface by
    deriving your own loader class.
 
    If you have a custom component or an application that embeds \QD, you can
    also use the QFormBuilder class provided by the QtDesigner module to create
    user interfaces from UI files.
 
    The QUiLoader class provides a collection of functions allowing you to
    create widgets based on the information stored in UI files (created
    with \QD) or available in the specified plugin paths. The specified plugin
    paths can be retrieved using the pluginPaths() function. Similarly, the
    contents of a UI file can be retrieved using the load() function. For
    example:
 
    \snippet quiloader/mywidget.cpp 0
 
    \if !defined(qtforpython)
    By including the user interface in the form's resources (\c myform.qrc), we
    ensure that it will be present at run-time:
 
    \quotefile quiloader/mywidget.qrc
    \endif
 
    The availableWidgets() function returns a QStringList with the class names
    of the widgets available in the specified plugin paths. To create these
    widgets, simply use the createWidget() function. For example:
 
    \snippet quiloader/main.cpp 0
 
    To make a custom widget available to the loader, you can use the
    addPluginPath() function; to remove all available widgets, you can call
    the clearPluginPaths() function.
 
    The createAction(), createActionGroup(), createLayout(), and createWidget()
    functions are used internally by the QUiLoader class whenever it has to
    create an action, action group, layout, or widget respectively. For that
    reason, you can subclass the QUiLoader class and reimplement these
    functions to intervene the process of constructing a user interface. For
    example, you might want to have a list of the actions created when loading
    a form or creating a custom widget.
 
    For a complete example using the QUiLoader class, see the
    \l{Calculator Builder}.
 
    \sa {Qt UI Tools}, QFormBuilder
*/
 
/*!
    Creates a form loader with the given \a parent.
*/
QUiLoader::QUiLoader(QObject *parent)
    : QObject(parent), d_ptr(new QUiLoaderPrivate)
{
    Q_D(QUiLoader);
 
#ifndef QT_NO_DATASTREAM
    static int metaTypeId = 0;
    if (!metaTypeId) {
        metaTypeId = qRegisterMetaType<QUiTranslatableStringValue>("QUiTranslatableStringValue");
    }
#endif // QT_NO_DATASTREAM
    d->builder.loader = this;
 
#if QT_CONFIG(library)
    QStringList paths;
    const QStringList &libraryPaths = QApplication::libraryPaths();
    for (const QString &path : libraryPaths) {
        QString libPath = path;
        libPath  += QDir::separator();
        libPath  += QStringLiteral("designer");
        paths.append(libPath);
    }
 
    d->builder.setPluginPath(paths);
#endif // QT_CONFIG(library)
}
 
/*!
    Destroys the loader.
*/
QUiLoader::~QUiLoader() = default;
 
/*!
    Loads a form from the given \a device and creates a new widget with the
    given \a parentWidget to hold its contents.
 
    \warning
    \include security_considerations.qdocinc
 
    \sa createWidget(), errorString()
*/
QWidget *QUiLoader::load(QIODevice *device, QWidget *parentWidget)
{
    Q_D(QUiLoader);
    // QXmlStreamReader will report errors on open failure.
    if (!device->isOpen())
        device->open(QIODevice::ReadOnly|QIODevice::Text);
    return d->builder.load(device, parentWidget);
}
 
/*!
    Returns a list naming the paths in which the loader will search when
    locating custom widget plugins.
 
    \sa addPluginPath(), clearPluginPaths()
*/
QStringList QUiLoader::pluginPaths() const
{
    Q_D(const QUiLoader);
    return d->builder.pluginPaths();
}
 
/*!
    Clears the list of paths in which the loader will search when locating
    plugins.
 
    \sa addPluginPath(), pluginPaths()
*/
void QUiLoader::clearPluginPaths()
{
    Q_D(QUiLoader);
    d->builder.clearPluginPaths();
}
 
/*!
    Adds the given \a path to the list of paths in which the loader will search
    when locating plugins.
 
    \warning Only set paths that you trust. Allowing untrusted users to create
    or add content in a specified path may lead to security vulnerabilities.
 
    \sa pluginPaths(), clearPluginPaths()
*/
void QUiLoader::addPluginPath(const QString &path)
{
    Q_D(QUiLoader);
    d->builder.addPluginPath(path);
}
 
/*!
    Creates a new widget with the given \a parent and \a name using the class
    specified by \a className. You can use this function to create any of the
    widgets returned by the availableWidgets() function.
 
    The function is also used internally by the QUiLoader class whenever it
    creates a widget. Hence, you can subclass QUiLoader and reimplement this
    function to intervene process of constructing a user interface or widget.
    However, in your implementation, ensure that you call QUiLoader's version
    first.
 
    \sa availableWidgets(), load()
*/
QWidget *QUiLoader::createWidget(const QString &className, QWidget *parent, const QString &name)
{
    Q_D(QUiLoader);
    return d->builder.defaultCreateWidget(className, parent, name);
}
 
/*!
    Creates a new layout with the given \a parent and \a name using the class
    specified by \a className.
 
    The function is also used internally by the QUiLoader class whenever it
    creates a widget. Hence, you can subclass QUiLoader and reimplement this
    function to intervene process of constructing a user interface or widget.
    However, in your implementation, ensure that you call QUiLoader's version
    first.
 
    \sa createWidget(), load()
*/
QLayout *QUiLoader::createLayout(const QString &className, QObject *parent, const QString &name)
{
    Q_D(QUiLoader);
    return d->builder.defaultCreateLayout(className, parent, name);
}
 
/*!
    Creates a new action group with the given \a parent and \a name.
 
    The function is also used internally by the QUiLoader class whenever it
    creates a widget. Hence, you can subclass QUiLoader and reimplement this
    function to intervene process of constructing a user interface or widget.
    However, in your implementation, ensure that you call QUiLoader's version
    first.
 
    \sa createAction(), createWidget(), load()
 */
QActionGroup *QUiLoader::createActionGroup(QObject *parent, const QString &name)
{
    Q_D(QUiLoader);
    return d->builder.defaultCreateActionGroup(parent, name);
}
 
/*!
    Creates a new action with the given \a parent and \a name.
 
    The function is also used internally by the QUiLoader class whenever it
    creates a widget. Hence, you can subclass QUiLoader and reimplement this
    function to intervene process of constructing a user interface or widget.
    However, in your implementation, ensure that you call QUiLoader's version
    first.
 
    \sa createActionGroup(), createWidget(), load()
*/
QAction *QUiLoader::createAction(QObject *parent, const QString &name)
{
    Q_D(QUiLoader);
    return d->builder.defaultCreateAction(parent, name);
}
 
/*!
    Returns a list naming all available widgets that can be built using the
    createWidget() function, i.e all the widgets specified within the given
    plugin paths.
 
    \sa pluginPaths(), createWidget()
 
*/
QStringList QUiLoader::availableWidgets() const
{
    Q_D(const QUiLoader);
 
    d->setupWidgetMap();
    widget_map available = *g_widgets();
 
    const auto &customWidgets = d->builder.customWidgets();
    for (QDesignerCustomWidgetInterface *plugin : customWidgets)
        available.insert(plugin->name(), true);
 
    return available.keys();
}
 
 
/*!
    \since 4.5
    Returns a list naming all available layouts that can be built using the
    createLayout() function
 
    \sa createLayout()
*/
 
QStringList QUiLoader::availableLayouts() const
{
    QStringList rc;
#define DECLARE_WIDGET(a, b)
#define DECLARE_LAYOUT(a, b) rc.push_back(QLatin1String(#a));
 
#include "widgets.table"
 
#undef DECLARE_WIDGET
#undef DECLARE_LAYOUT
    return rc;
}
 
/*!
    Sets the working directory of the loader to \a dir. The loader will look
    for other resources, such as icons and resource files, in paths relative to
    this directory.
 
    \warning Only set a directory that you trust. Allowing untrusted users to
    create or add content in the working directory may lead to security
    vulnerabilities.
 
    \sa workingDirectory()
*/
 
void QUiLoader::setWorkingDirectory(const QDir &dir)
{
    Q_D(QUiLoader);
    d->builder.setWorkingDirectory(dir);
}
 
/*!
    Returns the working directory of the loader.
 
    \sa setWorkingDirectory()
*/
 
QDir QUiLoader::workingDirectory() const
{
    Q_D(const QUiLoader);
    return d->builder.workingDirectory();
}
/*!
    \since 4.5
 
    If \a enabled is true, user interfaces loaded by this loader will
    automatically retranslate themselves upon receiving a language change
    event. Otherwise, the user interfaces will not be retranslated.
 
    \sa isLanguageChangeEnabled()
*/
 
void QUiLoader::setLanguageChangeEnabled(bool enabled)
{
    Q_D(QUiLoader);
    d->builder.dynamicTr = enabled;
}
 
/*!
    \since 4.5
 
    Returns true if dynamic retranslation on language change is enabled;
    returns false otherwise.
 
    \sa setLanguageChangeEnabled()
*/
 
bool QUiLoader::isLanguageChangeEnabled() const
{
    Q_D(const QUiLoader);
    return d->builder.dynamicTr;
}
 
/*!
    \internal
    \since 4.5
 
    If \a enabled is true, user interfaces loaded by this loader will be
    translated. Otherwise, the user interfaces will not be translated.
 
    \note This is orthogonal to languageChangeEnabled.
 
    \sa isLanguageChangeEnabled(), setLanguageChangeEnabled()
*/
 
void QUiLoader::setTranslationEnabled(bool enabled)
{
    Q_D(QUiLoader);
    d->builder.trEnabled = enabled;
}
 
/*!
    \internal
    \since 4.5
 
    Returns true if translation is enabled; returns false otherwise.
 
    \sa setTranslationEnabled()
*/
 
bool QUiLoader::isTranslationEnabled() const
{
    Q_D(const QUiLoader);
    return d->builder.trEnabled;
}
 
/*!
    Returns a human-readable description of the last error occurred in load().
 
    \since 5.0
    \sa load()
*/
 
QString QUiLoader::errorString() const
{
    Q_D(const QUiLoader);
    return d->builder.errorString();
}
 
QT_END_NAMESPACE
 
#include "quiloader.moc"