[pluginloader] Add methods to list containments using KPluginMetaData

To replace the KPluginInfo-based variants

autotests/pluginloadertest.cpp

@@ -55,6 +55,10 @@ void PluginTest::listContainmentsOfType()
     const KPluginInfo::List plugins = Plasma::PluginLoader::listContainmentsOfType(QStringLiteral("Desktop"));
     qDebug() << "Desktop Containments: " << plugins.count();
     QVERIFY(plugins.count() > 0 || m_buildonly);
+
+    const QList<KPluginMetaData> pluginsMetaData = Plasma::PluginLoader::listContainmentsMetaDataOfType(QStringLiteral("Desktop"));
+    qDebug() << "Desktop Containments MetaData: " << pluginsMetaData.count();
+    QVERIFY(pluginsMetaData.count() > 0 || m_buildonly);
 }
 
 static const auto source = QStringLiteral("Europe/Sofia");

src/plasma/pluginloader.cpp

@@ -663,6 +663,28 @@ KPluginInfo::List PluginLoader::listContainments(const QString &category, const
     return listContainmentsOfType(QString(), category, parentApp);
 }
 
+QList<KPluginMetaData> PluginLoader::listContainmentsMetaData(std::function<bool(const KPluginMetaData &)> filter)
+{
+    auto ownFilter = [filter](const KPluginMetaData &md) -> bool {
+        if (!md.serviceTypes().contains(QLatin1String("Plasma/Containment"))) {
+            return false;
+        }
+
+        return filter(md);
+    };
+
+    return KPackage::PackageLoader::self()->findPackages(QStringLiteral("Plasma/Applet"), QString(), ownFilter);
+}
+
+QList<KPluginMetaData> PluginLoader::listContainmentsMetaDataOfType(const QString &type)
+{
+    auto filter = [type](const KPluginMetaData &md) -> bool {
+        return md.value(QStringLiteral("X-Plasma-ContainmentType")) == type;
+    };
+
+    return listContainmentsMetaData(filter);
+}
+
 KPluginInfo::List PluginLoader::listContainmentsOfType(const QString &type, const QString &category, const QString &parentApp)
 {
     KConfigGroup group(KSharedConfig::openConfig(), "General");

src/plasma/pluginloader.h

@@ -280,6 +280,24 @@ public:
      **/
     static KPluginInfo::List listContainments(const QString &category = QString(), const QString &parentApp = QString());
 
+    /**
+     * Returns a list of all known containments.
+     *
+     * @param filter An optional predicate that can be used for filtering.
+     *
+     * @return list of containments
+     */
+    static QList<KPluginMetaData> listContainmentsMetaData(std::function<bool(const KPluginMetaData &)> filter = {});
+
+    /**
+     * Returns a list of containments of the specified type.
+     *
+     * @param type The target containment type
+     *
+     * @return list of containments
+     */
+    static QList<KPluginMetaData> listContainmentsMetaDataOfType(const QString &type);
+
     /**
      * Returns a list of all known containments that match the parameters.
      *