Copy ConfigPropertyMap from KDeclarative to new KConfig QML module

This way consumers which want to use the ConfigPropertyMap don't have to
pull in KDeclarative's entire dependency tree.

Also we can remove the automatic saving of the config, previously
this was opt-out - which makes is difficult to deprecate anything.

This way the API design is also more clear, since the object only takes care of exposing the
data to QML. The writing has to be done manually, which makes more sense anyways when we have
the notify opt-in.

As discussed on the KF6 weekly thread, an optional QML submodule is seen as the best
way to handle the QML dependency.

Task: https://phabricator.kde.org/T12131

Relates to https://phabricator.kde.org/T12126, after his change the KDeclarative stuff can be deprecated.
Because we don't register the property map in any QML plugin, there is
no conflict in duplicating and modifying it now.

1 files changed, 148 insertions, 0 deletions

diff --git a/src/qml/kconfigpropertymap.cpp b/src/qml/kconfigpropertymap.cpp
new file mode 100644
index 00000000..55b2991d
--- /dev/null
+++ b/src/qml/kconfigpropertymap.cpp
@@ -0,0 +1,148 @@
+/*
+    SPDX-FileCopyrightText: 2013 Marco Martin <notmart@gmail.com>
+    SPDX-FileCopyrightText: 2020 David Edmundson <davidedmundson@kde.org>
+    SPDX-FileCopyrightText: 2021 Alexander Lohnau <alexander.lohnau@gmx.de>
+
+    SPDX-License-Identifier: LGPL-2.0-or-later
+*/
+
+#include "kconfigpropertymap.h"
+
+#include <KCoreConfigSkeleton>
+#include <QJSValue>
+#include <QPointer>
+
+#include <functional>
+
+class KConfigPropertyMapPrivate
+{
+public:
+    KConfigPropertyMapPrivate(KConfigPropertyMap *map)
+        : q(map)
+    {
+    }
+
+    enum LoadConfigOption {
+        DontEmitValueChanged,
+        EmitValueChanged,
+    };
+
+    void loadConfig(LoadConfigOption option);
+    void writeConfig();
+    void writeConfigValue(const QString &key, const QVariant &value);
+
+    KConfigPropertyMap *q;
+    QPointer<KCoreConfigSkeleton> config;
+    bool updatingConfigValue = false;
+    bool autosave = true;
+    bool notify = false;
+};
+
+KConfigPropertyMap::KConfigPropertyMap(KCoreConfigSkeleton *config, QObject *parent)
+    : QQmlPropertyMap(this, parent)
+    , d(new KConfigPropertyMapPrivate(this))
+{
+    Q_ASSERT(config);
+    d->config = config;
+
+    // Reload the config only if the change signal has *not* been emitted by ourselves updating the config
+    connect(config, &KCoreConfigSkeleton::configChanged, this, [this]() {
+        if (!d->updatingConfigValue) {
+            d->loadConfig(KConfigPropertyMapPrivate::EmitValueChanged);
+        }
+    });
+    connect(this, &KConfigPropertyMap::valueChanged, this, [this](const QString &key, const QVariant &value) {
+        d->writeConfigValue(key, value);
+    });
+
+    d->loadConfig(KConfigPropertyMapPrivate::DontEmitValueChanged);
+}
+
+KConfigPropertyMap::~KConfigPropertyMap() = default;
+
+bool KConfigPropertyMap::isNotify() const
+{
+    return d->notify;
+}
+
+void KConfigPropertyMap::setNotify(bool notify)
+{
+    d->notify = notify;
+}
+
+void KConfigPropertyMap::writeConfig()
+{
+    d->writeConfig();
+}
+
+QVariant KConfigPropertyMap::updateValue(const QString &key, const QVariant &input)
+{
+    Q_UNUSED(key);
+    if (input.userType() == qMetaTypeId<QJSValue>()) {
+        return input.value<QJSValue>().toVariant();
+    }
+    return input;
+}
+
+bool KConfigPropertyMap::isImmutable(const QString &key) const
+{
+    KConfigSkeletonItem *item = d->config.data()->findItem(key);
+    if (item) {
+        return item->isImmutable();
+    }
+
+    return false;
+}
+
+void KConfigPropertyMapPrivate::loadConfig(KConfigPropertyMapPrivate::LoadConfigOption option)
+{
+    if (!config) {
+        return;
+    }
+
+    const auto &items = config.data()->items();
+    for (KConfigSkeletonItem *item : items) {
+        q->insert(item->key() + QStringLiteral("Default"), item->getDefault());
+        q->insert(item->key(), item->property());
+        if (option == EmitValueChanged) {
+            Q_EMIT q->valueChanged(item->key(), item->property());
+        }
+    }
+}
+
+void KConfigPropertyMapPrivate::writeConfig()
+{
+    if (!config) {
+        return;
+    }
+
+    const auto lstItems = config.data()->items();
+    for (KConfigSkeletonItem *item : lstItems) {
+        item->setWriteFlags(notify ? KConfigBase::Notify : KConfigBase::Normal);
+        item->setProperty(q->value(item->key()));
+    }
+
+    if (autosave) {
+        updatingConfigValue = true;
+        config.data()->save();
+        updatingConfigValue = false;
+    }
+}
+
+void KConfigPropertyMapPrivate::writeConfigValue(const QString &key, const QVariant &value)
+{
+    KConfigSkeletonItem *item = config.data()->findItem(key);
+    if (item) {
+        updatingConfigValue = true;
+        item->setWriteFlags(notify ? KConfigBase::Notify : KConfigBase::Normal);
+        item->setProperty(value);
+        if (autosave) {
+            config.data()->save();
+            // why read? read will update KConfigSkeletonItem::mLoadedValue,
+            // allowing a write operation to be performed next time
+            config.data()->read();
+        }
+        updatingConfigValue = false;
+    }
+}
+