Add KPropertySkeletonItem

Summary:
This new item allows to use a QObject property as a source for a
setting. This is especially convenient for using with KCMs present in
systemsettings which tend to store information outside of KConfig (for
interfacing deeper with the system).

Reviewers: #frameworks, dfaure, davidedmundson, bport, crossi

Subscribers: kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D25211

src/core/kcoreconfigskeleton.cpp

@@ -183,6 +183,69 @@ void KConfigSkeletonItem::setIsSaveNeededImpl(const std::function<bool ()> &impl
     d->mIsSaveNeededImpl = impl;
 }
 
+KPropertySkeletonItem::KPropertySkeletonItem(QObject *object, const QByteArray &propertyName, const QVariant &defaultValue)
+    : KConfigSkeletonItem(*new KPropertySkeletonItemPrivate(object, propertyName, defaultValue), {}, {})
+{
+    setIsDefaultImpl([this] {
+        Q_D(const KPropertySkeletonItem);
+        return d->mReference == d->mDefaultValue;
+    });
+    setIsSaveNeededImpl([this] {
+        Q_D(const KPropertySkeletonItem);
+        return d->mReference != d->mLoadedValue;
+    });
+}
+
+QVariant KPropertySkeletonItem::property() const
+{
+    Q_D(const KPropertySkeletonItem);
+    return d->mReference;
+}
+
+void KPropertySkeletonItem::setProperty(const QVariant &p)
+{
+    Q_D(KPropertySkeletonItem);
+    d->mReference = p;
+}
+
+bool KPropertySkeletonItem::isEqual(const QVariant &p) const
+{
+    Q_D(const KPropertySkeletonItem);
+    return d->mReference == p;
+}
+
+void KPropertySkeletonItem::readConfig(KConfig *)
+{
+    Q_D(KPropertySkeletonItem);
+    d->mReference = d->mObject->property(d->mPropertyName.constData());
+    d->mLoadedValue = d->mReference;
+}
+
+void KPropertySkeletonItem::writeConfig(KConfig *)
+{
+    Q_D(KPropertySkeletonItem);
+    d->mObject->setProperty(d->mPropertyName.constData(), d->mReference);
+    d->mLoadedValue = d->mReference;
+}
+
+void KPropertySkeletonItem::readDefault(KConfig *)
+{
+    Q_D(KPropertySkeletonItem);
+    d->mReference = d->mConstDefaultValue;
+}
+
+void KPropertySkeletonItem::setDefault()
+{
+    Q_D(KPropertySkeletonItem);
+    d->mReference = d->mDefaultValue;
+}
+
+void KPropertySkeletonItem::swapDefault()
+{
+    Q_D(KPropertySkeletonItem);
+    std::swap(d->mReference, d->mDefaultValue);
+}
+
 KCoreConfigSkeleton::ItemString::ItemString(const QString &_group, const QString &_key,
         QString &reference,
         const QString &defaultValue,

src/core/kcoreconfigskeleton.h

@@ -247,6 +247,56 @@ protected:
     KConfigSkeletonItemPrivate *const d_ptr;
 };
 
+class KPropertySkeletonItemPrivate;
+
+/**
+ * \class KPropertySkeletonItem kcoreconfigskeleton.h <KCoreConfigSkeleton>
+ *
+ * @short Class for proxying a QObject property as a preferences setting
+ * @author Kevin Ottens
+ * @see KConfigSkeletonItem
+ *
+ * This class represents one preferences setting as used by @ref KCoreConfigSkeleton.
+ * Unlike other @ref KConfigSkeletonItem subclasses, this one won't store the preference
+ * in KConfig but will use a QObject property as storage.
+ * You will have to register instances of this class with the function KCoreConfigSkeleton::addItem().
+ *
+ * @since 5.65
+ */
+class KCONFIGCORE_EXPORT KPropertySkeletonItem : public KConfigSkeletonItem
+{
+    Q_DECLARE_PRIVATE(KPropertySkeletonItem)
+public:
+    /**
+     * Constructor
+     *
+     * @param object The QObject instance which we'll manage the property of
+     * @param propertyName The name of the property in @p object which we'll manage
+     * @param defaultValue The default value of the property
+     */
+    KPropertySkeletonItem(QObject *object, const QByteArray &propertyName, const QVariant &defaultValue);
+
+    /** @copydoc KConfigSkeletonItem::property() */
+    QVariant property() const override;
+    /** @copydoc KConfigSkeletonItem::setProperty(const QVariant &) */
+    void setProperty(const QVariant &p) override;
+    /** @copydoc KConfigSkeletonItem::isEqual(const QVariant &) */
+    bool isEqual(const QVariant &p) const override;
+
+    /** @copydoc KConfigSkeletonItem::readConfig(KConfig *) */
+    void readConfig(KConfig *) override;
+    /** @copydoc KConfigSkeletonItem::writeConfig(KConfig *) */
+    void writeConfig(KConfig *) override;
+
+    /** @copydoc KConfigSkeletonItem::readDefault(KConfig *) */
+    void readDefault(KConfig *) override;
+    /** @copydoc KConfigSkeletonItem::setDefault() */
+    void setDefault() override;
+    /** @copydoc KConfigSkeletonItem::swapDefault() */
+    void swapDefault() override;
+};
+
+
 /**
  * \class KConfigSkeletonGenericItem kcoreconfigskeleton.h <KConfigSkeletonGenericItem>
  */

src/core/kcoreconfigskeleton_p.h

@@ -67,4 +67,26 @@ public:
     std::function<bool()> mIsSaveNeededImpl;
 };
 
+class KPropertySkeletonItemPrivate : public KConfigSkeletonItemPrivate
+{
+public:
+    KPropertySkeletonItemPrivate(QObject *object, const QByteArray &propertyName, const QVariant &defaultValue)
+        : KConfigSkeletonItemPrivate()
+        , mObject(object)
+        , mPropertyName(propertyName)
+        , mDefaultValue(defaultValue)
+        , mConstDefaultValue(defaultValue)
+    {
+        mIsImmutable = false;
+    }
+
+    QObject *mObject;
+    const QByteArray mPropertyName;
+    QVariant mDefaultValue;
+    const QVariant mConstDefaultValue;
+    QVariant mReference;
+    QVariant mLoadedValue;
+};
+
+
 #endif