Qt.labs.settings: Make plugin optional

This moves the settings types into a new library and is meant to make
them availabe to the QML compiler at some point in the future.

Task-number: QTBUG-90487
Change-Id: I986615b08ea8c1a7312b9d9c6ae0b13c03fb5497
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

4 files changed, 3 insertions, 643 deletions

diff --git a/src/imports/settings/CMakeLists.txt b/src/imports/settings/CMakeLists.txt
index c5c76135ba..f49e741106 100644
--- a/src/imports/settings/CMakeLists.txt
+++ b/src/imports/settings/CMakeLists.txt
@@ -9,14 +9,13 @@ qt_internal_add_qml_module(qmlsettingsplugin
     VERSION "${CMAKE_PROJECT_VERSION}"
     CLASSNAME QmlSettingsPlugin
     SKIP_TYPE_REGISTRATION
-    GENERATE_QMLTYPES
-    INSTALL_QMLTYPES
+    PLUGIN_OPTIONAL
     SOURCES
         plugin.cpp
-        qqmlsettings.cpp qqmlsettings_p.h
     PUBLIC_LIBRARIES
         Qt::Core
         Qt::Qml
+        Qt::LabsSettingsPrivate
 )
 
 #### Keys ignored in scope 1:.:.:settings.pro:<TRUE>:
diff --git a/src/imports/settings/plugin.cpp b/src/imports/settings/plugin.cpp
index e8e640412b..428bd27198 100644
--- a/src/imports/settings/plugin.cpp
+++ b/src/imports/settings/plugin.cpp
@@ -40,9 +40,7 @@
 #include <QtQml/qqmlextensionplugin.h>
 #include <QtQml/qqml.h>
 
-#include "qqmlsettings_p.h"
-
-extern void qml_register_types_Qt_labs_settings();
+#include <QtLabsSettings/private/qqmlsettingsglobal_p.h>
 
 QT_BEGIN_NAMESPACE
 
diff --git a/src/imports/settings/qqmlsettings.cpp b/src/imports/settings/qqmlsettings.cpp
deleted file mode 100644
index ff8ec5e065..0000000000
--- a/src/imports/settings/qqmlsettings.cpp
+++ /dev/null
@@ -1,534 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the examples 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 "qqmlsettings_p.h"
-#include <qcoreevent.h>
-#include <qcoreapplication.h>
-#include <qloggingcategory.h>
-#include <qsettings.h>
-#include <qpointer.h>
-#include <qjsvalue.h>
-#include <qqmlinfo.h>
-#include <qdebug.h>
-#include <qhash.h>
-
-QT_BEGIN_NAMESPACE
-
-/*!
-    \qmlmodule Qt.labs.settings 1.0
-    \title Qt Labs Settings QML Types
-    \ingroup qmlmodules
-    \brief Provides persistent platform-independent application settings.
-
-    To use this module, import the module with the following line:
-
-    \code
-    import Qt.labs.settings
-    \endcode
-*/
-
-/*!
-    \qmltype Settings
-    \instantiates QQmlSettings
-    \inqmlmodule Qt.labs.settings
-    \ingroup settings
-    \brief Provides persistent platform-independent application settings.
-
-    The Settings type provides persistent platform-independent application settings.
-
-    \note This type is made available by importing the \b Qt.labs.settings module.
-    \e {Types in the Qt.labs module are not guaranteed to remain compatible
-    in future versions.}
-
-    Users normally expect an application to remember its settings (window sizes
-    and positions, options, etc.) across sessions. The Settings type enables you
-    to save and restore such application settings with the minimum of effort.
-
-    Individual setting values are specified by declaring properties within a
-    Settings element. All \l {QML Basic Types}{basic type} properties are
-    supported. The recommended approach is to use property aliases in order
-    to get automatic property updates both ways. The following example shows
-    how to use Settings to store and restore the geometry of a window.
-
-    \qml
-    import QtQuick.Window
-    import Qt.labs.settings
-
-    Window {
-        id: window
-
-        width: 800
-        height: 600
-
-        Settings {
-            property alias x: window.x
-            property alias y: window.y
-            property alias width: window.width
-            property alias height: window.height
-        }
-    }
-    \endqml
-
-    At first application startup, the window gets default dimensions specified
-    as 800x600. Notice that no default position is specified - we let the window
-    manager handle that. Later when the window geometry changes, new values will
-    be automatically stored to the persistent settings. The second application
-    run will get initial values from the persistent settings, bringing the window
-    back to the previous position and size.
-
-    A fully declarative syntax, achieved by using property aliases, comes at the
-    cost of storing persistent settings whenever the values of aliased properties
-    change. Normal properties can be used to gain more fine-grained control over
-    storing the persistent settings. The following example illustrates how to save
-    a setting on component destruction.
-
-    \qml
-    import QtQuick
-    import Qt.labs.settings
-
-    Item {
-        id: page
-
-        state: settings.state
-
-        states: [
-            State {
-                name: "active"
-                // ...
-            },
-            State {
-                name: "inactive"
-                // ...
-            }
-        ]
-
-        Settings {
-            id: settings
-            property string state: "active"
-        }
-
-        Component.onDestruction: {
-            settings.state = page.state
-        }
-    }
-    \endqml
-
-    Notice how the default value is now specified in the persistent setting property,
-    and the actual property is bound to the setting in order to get the initial value
-    from the persistent settings.
-
-    \section1 Application Identifiers
-
-    Application specific settings are identified by providing application
-    \l {QCoreApplication::applicationName}{name},
-    \l {QCoreApplication::organizationName}{organization} and
-    \l {QCoreApplication::organizationDomain}{domain}, or by specifying
-    \l fileName.
-
-    \code
-    #include <QGuiApplication>
-    #include <QQmlApplicationEngine>
-
-    int main(int argc, char *argv[])
-    {
-        QGuiApplication app(argc, argv);
-        app.setOrganizationName("Some Company");
-        app.setOrganizationDomain("somecompany.com");
-        app.setApplicationName("Amazing Application");
-
-        QQmlApplicationEngine engine("main.qml");
-        return app.exec();
-    }
-    \endcode
-
-    These are typically specified in C++ in the beginning of \c main(),
-    but can also be controlled in QML via the following properties:
-    \list
-        \li \l {Qt::application}{Qt.application.name},
-        \li \l {Qt::application}{Qt.application.organization} and
-        \li \l {Qt::application}{Qt.application.domain}.
-    \endlist
-
-    \section1 Categories
-
-    Application settings may be divided into logical categories by specifying
-    a category name via the \l category property. Using logical categories not
-    only provides a cleaner settings structure, but also prevents possible
-    conflicts between setting keys.
-
-    If several categories are required, use several Settings objects, each with
-    their own category:
-
-    \qml
-    Item {
-        id: panel
-
-        visible: true
-
-        Settings {
-            category: "OutputPanel"
-            property alias visible: panel.visible
-            // ...
-        }
-
-        Settings {
-            category: "General"
-            property alias fontSize: fontSizeSpinBox.value
-            // ...
-        }
-    }
-    \endqml
-
-    Instead of ensuring that all settings in the application have unique names,
-    the settings can be divided into unique categories that may then contain
-    settings using the same names that are used in other categories - without
-    a conflict.
-
-    \section1 Notes
-
-    The current implementation is based on \l QSettings. This imposes certain
-    limitations, such as missing change notifications. Writing a setting value
-    using one instance of Settings does not update the value in another Settings
-    instance, even if they are referring to the same setting in the same category.
-
-    The information is stored in the system registry on Windows, and in XML
-    preferences files on \macos. On other Unix systems, in the absence of a
-    standard, INI text files are used. See \l QSettings documentation for
-    more details.
-
-    \sa QSettings
-*/
-
-Q_LOGGING_CATEGORY(lcSettings, "qt.labs.settings")
-
-static const int settingsWriteDelay = 500;
-
-class QQmlSettingsPrivate
-{
-    Q_DECLARE_PUBLIC(QQmlSettings)
-
-public:
-    QQmlSettingsPrivate();
-
-    QSettings *instance() const;
-
-    void init();
-    void reset();
-
-    void load();
-    void store();
-
-    void _q_propertyChanged();
-    QVariant readProperty(const QMetaProperty &property) const;
-
-    QQmlSettings *q_ptr = nullptr;
-    int timerId = 0;
-    bool initialized = false;
-    QString category;
-    QString fileName;
-    mutable QPointer<QSettings> settings;
-    QHash<const char *, QVariant> changedProperties;
-};
-
-QQmlSettingsPrivate::QQmlSettingsPrivate() {}
-
-QSettings *QQmlSettingsPrivate::instance() const
-{
-    if (!settings) {
-        QQmlSettings *q = const_cast<QQmlSettings*>(q_func());
-        settings = fileName.isEmpty() ? new QSettings(q) : new QSettings(fileName, QSettings::IniFormat, q);
-        if (settings->status() != QSettings::NoError) {
-            // TODO: can't print out the enum due to the following error:
-            // error: C2666: 'QQmlInfo::operator <<': 15 overloads have similar conversions
-            qmlWarning(q) << "Failed to initialize QSettings instance. Status code is: " << int(settings->status());
-
-            if (settings->status() == QSettings::AccessError) {
-                QVector<QString> missingIdentifiers;
-                if (QCoreApplication::organizationName().isEmpty())
-                    missingIdentifiers.append(QLatin1String("organizationName"));
-                if (QCoreApplication::organizationDomain().isEmpty())
-                    missingIdentifiers.append(QLatin1String("organizationDomain"));
-                if (QCoreApplication::applicationName().isEmpty())
-                    missingIdentifiers.append(QLatin1String("applicationName"));
-
-                if (!missingIdentifiers.isEmpty())
-                    qmlWarning(q) << "The following application identifiers have not been set: " << missingIdentifiers;
-            }
-            return settings;
-        }
-
-        if (!category.isEmpty())
-            settings->beginGroup(category);
-        if (initialized)
-            q->d_func()->load();
-    }
-    return settings;
-}
-
-void QQmlSettingsPrivate::init()
-{
-    if (!initialized) {
-        qCDebug(lcSettings) << "QQmlSettings: stored at" << instance()->fileName();
-        load();
-        initialized = true;
-    }
-}
-
-void QQmlSettingsPrivate::reset()
-{
-    if (initialized && settings && !changedProperties.isEmpty())
-        store();
-    delete settings;
-}
-
-void QQmlSettingsPrivate::load()
-{
-    Q_Q(QQmlSettings);
-    const QMetaObject *mo = q->metaObject();
-    const int offset = mo->propertyOffset();
-    const int count = mo->propertyCount();
-
-    // don't save built-in properties if there aren't any qml properties
-    if (offset == 1)
-        return;
-
-    for (int i = offset; i < count; ++i) {
-        QMetaProperty property = mo->property(i);
-
-        const QVariant previousValue = readProperty(property);
-        const QVariant currentValue = instance()->value(property.name(), previousValue);
-
-        if (!currentValue.isNull() && (!previousValue.isValid()
-                || (currentValue.canConvert(previousValue.metaType())
-                    && previousValue != currentValue))) {
-            property.write(q, currentValue);
-            qCDebug(lcSettings) << "QQmlSettings: load" << property.name() << "setting:" << currentValue << "default:" << previousValue;
-        }
-
-        // ensure that a non-existent setting gets written
-        // even if the property wouldn't change later
-        if (!instance()->contains(property.name()))
-            _q_propertyChanged();
-
-        // setup change notifications on first load
-        if (!initialized && property.hasNotifySignal()) {
-            static const int propertyChangedIndex = mo->indexOfSlot("_q_propertyChanged()");
-            QMetaObject::connect(q, property.notifySignalIndex(), q, propertyChangedIndex);
-        }
-    }
-}
-
-void QQmlSettingsPrivate::store()
-{
-    QHash<const char *, QVariant>::const_iterator it = changedProperties.constBegin();
-    while (it != changedProperties.constEnd()) {
-        instance()->setValue(it.key(), it.value());
-        qCDebug(lcSettings) << "QQmlSettings: store" << it.key() << ":" << it.value();
-        ++it;
-    }
-    changedProperties.clear();
-}
-
-void QQmlSettingsPrivate::_q_propertyChanged()
-{
-    Q_Q(QQmlSettings);
-    const QMetaObject *mo = q->metaObject();
-    const int offset = mo->propertyOffset();
-    const int count = mo->propertyCount();
-    for (int i = offset; i < count; ++i) {
-        const QMetaProperty &property = mo->property(i);
-        const QVariant value = readProperty(property);
-        changedProperties.insert(property.name(), value);
-        qCDebug(lcSettings) << "QQmlSettings: cache" << property.name() << ":" << value;
-    }
-    if (timerId != 0)
-        q->killTimer(timerId);
-    timerId = q->startTimer(settingsWriteDelay);
-}
-
-QVariant QQmlSettingsPrivate::readProperty(const QMetaProperty &property) const
-{
-    Q_Q(const QQmlSettings);
-    QVariant var = property.read(q);
-    if (var.userType() == qMetaTypeId<QJSValue>())
-        var = var.value<QJSValue>().toVariant();
-    return var;
-}
-
-QQmlSettings::QQmlSettings(QObject *parent)
-    : QObject(parent), d_ptr(new QQmlSettingsPrivate)
-{
-    Q_D(QQmlSettings);
-    d->q_ptr = this;
-}
-
-QQmlSettings::~QQmlSettings()
-{
-    Q_D(QQmlSettings);
-    d->reset(); // flush pending changes
-}
-
-/*!
-    \qmlproperty string Settings::category
-
-    This property holds the name of the settings category.
-
-    Categories can be used to group related settings together.
-*/
-QString QQmlSettings::category() const
-{
-    Q_D(const QQmlSettings);
-    return d->category;
-}
-
-void QQmlSettings::setCategory(const QString &category)
-{
-    Q_D(QQmlSettings);
-    if (d->category != category) {
-        d->reset();
-        d->category = category;
-        if (d->initialized)
-            d->load();
-    }
-}
-
-/*!
-    \qmlproperty string Settings::fileName
-
-    This property holds the path to the settings file. If the file doesn't
-    already exist, it is created.
-
-    \since Qt 5.12
-
-    \sa QSettings::fileName, QSettings::IniFormat
-*/
-QString QQmlSettings::fileName() const
-{
-    Q_D(const QQmlSettings);
-    return d->fileName;
-}
-
-void QQmlSettings::setFileName(const QString &fileName)
-{
-    Q_D(QQmlSettings);
-    if (d->fileName != fileName) {
-        d->reset();
-        d->fileName = fileName;
-        if (d->initialized)
-            d->load();
-    }
-}
-
-/*!
-   \qmlmethod var Settings::value(string key, var defaultValue)
-
-   Returns the value for setting \a key. If the setting doesn't exist,
-   returns \a defaultValue.
-
-   \since Qt 5.12
-
-   \sa QSettings::value
-*/
-QVariant QQmlSettings::value(const QString &key, const QVariant &defaultValue) const
-{
-    Q_D(const QQmlSettings);
-    return d->instance()->value(key, defaultValue);
-}
-
-/*!
-   \qmlmethod Settings::setValue(string key, var value)
-
-   Sets the value of setting \a key to \a value. If the key already exists,
-   the previous value is overwritten.
-
-   \since Qt 5.12
-
-   \sa QSettings::setValue
-*/
-void QQmlSettings::setValue(const QString &key, const QVariant &value)
-{
-    Q_D(const QQmlSettings);
-    d->instance()->setValue(key, value);
-    qCDebug(lcSettings) << "QQmlSettings: setValue" << key << ":" << value;
-}
-
-/*!
-   \qmlmethod Settings::sync()
-
-    Writes any unsaved changes to permanent storage, and reloads any
-    settings that have been changed in the meantime by another
-    application.
-
-    This function is called automatically from QSettings's destructor and
-    by the event loop at regular intervals, so you normally don't need to
-    call it yourself.
-
-   \sa QSettings::sync
-*/
-void QQmlSettings::sync()
-{
-    Q_D(QQmlSettings);
-    d->instance()->sync();
-}
-
-void QQmlSettings::classBegin()
-{
-}
-
-void QQmlSettings::componentComplete()
-{
-    Q_D(QQmlSettings);
-    d->init();
-}
-
-void QQmlSettings::timerEvent(QTimerEvent *event)
-{
-    Q_D(QQmlSettings);
-    if (event->timerId() == d->timerId) {
-        killTimer(d->timerId);
-        d->timerId = 0;
-
-        d->store();
-    }
-    QObject::timerEvent(event);
-}
-
-QT_END_NAMESPACE
-
-#include "moc_qqmlsettings_p.cpp"
diff --git a/src/imports/settings/qqmlsettings_p.h b/src/imports/settings/qqmlsettings_p.h
deleted file mode 100644
index 100d0136ff..0000000000
--- a/src/imports/settings/qqmlsettings_p.h
+++ /dev/null
@@ -1,103 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the examples 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 QQMLSETTINGS_P_H
-#define QQMLSETTINGS_P_H
-
-//
-//  W A R N I N G
-//  -------------
-//
-// This file is not part of the Qt API.  It exists purely as an
-// implementation detail.  This header file may change from version to
-// version without notice, or even be removed.
-//
-// We mean it.
-//
-
-#include <QtQml/qqml.h>
-#include <QtCore/qobject.h>
-#include <QtCore/qscopedpointer.h>
-#include <QtQml/qqmlparserstatus.h>
-
-QT_BEGIN_NAMESPACE
-
-class QQmlSettingsPrivate;
-
-class QQmlSettings : public QObject, public QQmlParserStatus
-{
-    Q_OBJECT
-    Q_INTERFACES(QQmlParserStatus)
-    Q_PROPERTY(QString category READ category WRITE setCategory FINAL)
-    Q_PROPERTY(QString fileName READ fileName WRITE setFileName FINAL)
-    QML_NAMED_ELEMENT(Settings)
-    QML_ADDED_IN_VERSION(1, 0)
-
-public:
-    explicit QQmlSettings(QObject *parent = 0);
-    ~QQmlSettings();
-
-    QString category() const;
-    void setCategory(const QString &category);
-
-    QString fileName() const;
-    void setFileName(const QString &fileName);
-
-    Q_INVOKABLE QVariant value(const QString &key, const QVariant &defaultValue = QVariant()) const;
-    Q_INVOKABLE void setValue(const QString &key, const QVariant &value);
-    Q_INVOKABLE void sync();
-
-protected:
-    void timerEvent(QTimerEvent *event) override;
-
-    void classBegin() override;
-    void componentComplete() override;
-
-private:
-    Q_DISABLE_COPY(QQmlSettings)
-    Q_DECLARE_PRIVATE(QQmlSettings)
-    QScopedPointer<QQmlSettingsPrivate> d_ptr;
-    Q_PRIVATE_SLOT(d_func(), void _q_propertyChanged())
-};
-
-QT_END_NAMESPACE
-
-QML_DECLARE_TYPE(QQmlSettings)
-
-#endif // QQMLSETTINGS_P_H