Don't enforce metadata.desktop, cleanup constructor

Makes it possible to use plugins that offer a metadata.json file.
Define the service type when falling back to the desktop file parser, so
the type system is proper.
Don't destroy a KPluginMetadata tuple to instanciate it right away.

REVIEW: 129102

src/plasma/applet.cpp

@@ -60,6 +60,13 @@
 namespace Plasma
 {
 
+static KPluginMetaData appletMetadataForDirectory(const QString &path)
+{
+    return QFile::exists(path + QLatin1String("/metadata.json"))
+                ? KPluginMetaData(path + QLatin1String("/metadata.json"))
+                : KPluginMetaData::fromDesktopFile(path + QLatin1String("/metadata.desktop"), { QStringLiteral("plasma-applet.desktop") });
+}
+
 Applet::Applet(const KPluginMetaData &info, QObject *parent, uint appletId)
     :  QObject(parent),
        d(new AppletPrivate(info, appletId, this))
@@ -88,14 +95,19 @@ Applet::Applet(QObject *parent, const QString &serviceID, uint appletId)
 
 Applet::Applet(QObject *parentObject, const QVariantList &args)
     :  QObject(0),
-       d(new AppletPrivate(
+       d(new AppletPrivate(KPluginMetaData(), args.count() > 1 ? args[1].toInt() : 0, this))
-             KPluginMetaData(args.count() > 0 && args.first().canConvert<QString>() ? args[0].toString() : QString()),
-             args.count() > 1 ? args[1].toInt() : 0, this))
 {
     setParent(parentObject);
-    if (args.count() > 0 && args.first().canConvert<QVariantMap>()) {
+    if (args.count() > 0) {
-        d->appletDescription = KPluginInfo(args).toMetaData();
+        const QVariant first = args.first();
+        if (first.canConvert<QString>()) {
+            d->appletDescription = KPluginMetaData(first.toString());
+        } else if (first.canConvert<QVariantMap>()) {
+            auto metadata = first.toMap().value(QStringLiteral("MetaData")).toMap();
+            d->appletDescription = KPluginMetaData(QJsonObject::fromVariantMap(metadata), {});
+        }
     }
+    d->icon = d->appletDescription.iconName();
 
     if (args.contains("org.kde.plasma:force-create")) {
         setProperty("org.kde.plasma:force-create", true);
@@ -109,7 +121,7 @@ Applet::Applet(QObject *parentObject, const QVariantList &args)
 
 Applet::Applet(const QString &packagePath, uint appletId)
     : QObject(0),
-      d(new AppletPrivate(KPluginMetaData(packagePath + QStringLiteral("/metadata.desktop")), appletId, this))
+      d(new AppletPrivate(appletMetadataForDirectory(packagePath), appletId, this))
 {
     d->init(packagePath);
     d->setupPackage();
@@ -767,15 +779,14 @@ bool Applet::hasValidAssociatedApplication() const
 
 Applet *Applet::loadPlasmoid(const QString &path, uint appletId)
 {
-    const QString metadataPath = path + QLatin1String("/metadata.desktop");
+    const KPluginMetaData md = appletMetadataForDirectory(path);
-    if (QFile::exists(metadataPath)) {
+    if (md.isValid()) {
-        KService service(metadataPath);
+        QStringList types = md.serviceTypes();
-        const QStringList &types = service.serviceTypes();
 
         if (types.contains(QStringLiteral("Plasma/Containment"))) {
-            return new Containment(path, appletId);
+            return new Containment(md, appletId);
         } else {
-            return new Applet(path, appletId);
+            return new Applet(md, nullptr, appletId);
         }
     }
 

src/plasma/containment.cpp

@@ -79,8 +79,8 @@ Containment::Containment(QObject *parent, const QVariantList &args)
     setHasConfigurationInterface(true);
 }
 
-Containment::Containment(const QString &packagePath, uint appletId)
+Containment::Containment(const KPluginMetaData &md, uint appletId)
-    : Applet(packagePath, appletId),
+    : Applet(md, nullptr, appletId),
       d(new ContainmentPrivate(this))
 {
     // WARNING: do not access config() OR globalConfig() in this method!

src/plasma/containment.h

@@ -330,7 +330,7 @@ private:
      * @param parent a QObject parent; you probably want to pass in 0
      * @since 4.3
      */
-    Containment(const QString &packagePath, uint appletId);
+    Containment(const KPluginMetaData &md, uint appletId);
 
     Q_PRIVATE_SLOT(d, void appletDeleted(Plasma::Applet *))
     Q_PRIVATE_SLOT(d, void triggerShowAddWidgets())

src/plasma/pluginloader.cpp

@@ -221,7 +221,7 @@ Applet *PluginLoader::loadApplet(const QString &name, uint appletId, const QVari
         p.setRequired("mainscript", false);
         p.setPath(name);
 
-        KPluginMetaData md(p.filePath("metadata"));
+        const KPluginMetaData md(p.metadata());
         const KPackage::Package fp = KPackage::PackageLoader::self()->loadPackage(QStringLiteral("Plasma/Applet"), md.value(QStringLiteral("X-Plasma-RootPath")));
         p.setFallbackPackage(fp);
 
@@ -234,8 +234,7 @@ Applet *PluginLoader::loadApplet(const QString &name, uint appletId, const QVari
     if (!applet) {
         //qCDebug(LOG_PLASMA) << name << "not a C++ applet: Falling back to an empty one";
 
-        QVariantList allArgs;
+        QVariantList allArgs = { p.metadata().fileName(), appletId, args };
-        allArgs << p.metadata().fileName() << appletId << args;
 
         if (p.metadata().serviceTypes().contains(QStringLiteral("Plasma/Containment"))) {
             return new Containment(0, allArgs);
@@ -499,42 +498,22 @@ Package PluginLoader::loadPackage(const QString &packageFormat, const QString &s
     return Package();
 }
 
-KPluginInfo::List PluginLoader::listAppletInfo(const QString &category, const QString &parentApp)
+QList<KPluginMetaData> PluginLoader::listAppletMetaData(const QString &category, const QString &parentApp)
 {
-    KPluginInfo::List list;
-
-    if (!d->isDefaultLoader && (parentApp.isEmpty() || parentApp == QCoreApplication::instance()->applicationName())) {
-        list = internalAppletInfo(category);
-    }
-
     //FIXME: this assumes we are always use packages.. no pure c++
+    std::function<bool(const KPluginMetaData&)> filter;
     if (category.isEmpty()) { //use all but the excluded categories
         KConfigGroup group(KSharedConfig::openConfig(), "General");
         QStringList excluded = group.readEntry("ExcludeCategories", QStringList());
 
-        auto filter = [&excluded, &parentApp](const KPluginMetaData &md) -> bool
+        filter = [excluded, parentApp](const KPluginMetaData &md) -> bool
         {
             const QString pa = md.value(QStringLiteral("X-KDE-ParentApp"));
             return (pa.isEmpty() || pa == parentApp) && !excluded.contains(md.category());
         };
-
-        //NOTE: it still produces kplugininfos from KServices because some user code expects
-        //info.sevice() to be valid and would crash ohtherwise
-        auto plugins = KPackage::PackageLoader::self()->findPackages(QStringLiteral("Plasma/Applet"), QString(), filter);
-        foreach (auto& md, plugins) {
-            auto pi = KPluginInfo(KService::serviceByStorageId(md.metaDataFileName()));
-            if (!pi.isValid()) {
-                qCWarning(LOG_PLASMA) << "Could not load plugin info for plugin :" << md.pluginId() << "skipping plugin";
-                continue;
-            }
-            list << pi;
-        }
-        return list;
-
-
     } else { //specific category (this could be an excluded one - is that bad?)
 
-        auto filter = [&category, &parentApp](const KPluginMetaData &md) -> bool
+        filter = [category, parentApp](const KPluginMetaData &md) -> bool
         {
             const QString pa = md.value(QStringLiteral("X-KDE-ParentApp"));
             if (category == QLatin1String("Miscellaneous")) {
@@ -543,21 +522,31 @@ KPluginInfo::List PluginLoader::listAppletInfo(const QString &category, const QS
                 return (pa.isEmpty() || pa == parentApp) && md.category() == category;
             }
         };
-
-
-        //NOTE: it still produces kplugininfos from KServices because some user code expects
-        //info.sevice() to be valid and would crash ohtherwise
-        const auto plugins = KPackage::PackageLoader::self()->findPackages(QStringLiteral("Plasma/Applet"), QString(), filter);
-        foreach (auto& md, plugins) {
-            auto pi =  KPluginInfo(KService::serviceByStorageId(md.metaDataFileName()));
-            if (!pi.isValid()) {
-                qCWarning(LOG_PLASMA) << "Could not load plugin info for plugin :" << md.pluginId() << "skipping plugin";
-                continue;
-            }
-            list << pi;
-        }
-        return list;
     }
+
+    QList<KPluginMetaData> list;
+    if (!d->isDefaultLoader && (parentApp.isEmpty() || parentApp == QCoreApplication::instance()->applicationName())) {
+        list = KPluginInfo::toMetaData(internalAppletInfo(category)).toList();
+    }
+    return KPackage::PackageLoader::self()->findPackages(QStringLiteral("Plasma/Applet"), QString(), filter);
+}
+
+KPluginInfo::List PluginLoader::listAppletInfo(const QString &category, const QString &parentApp)
+{
+    KPluginInfo::List list;
+    const auto plugins = listAppletMetaData(category, parentApp);
+
+    //NOTE: it still produces kplugininfos from KServices because some user code expects
+    //info.sevice() to be valid and would crash ohtherwise
+    foreach (auto& md, plugins) {
+        auto pi = md.metaDataFileName().endsWith(".json") ? KPluginInfo(md) : KPluginInfo(KService::serviceByStorageId(md.metaDataFileName()));
+        if (!pi.isValid()) {
+            qCWarning(LOG_PLASMA) << "Could not load plugin info for plugin :" << md.pluginId() << "skipping plugin";
+            continue;
+        }
+        list << pi;
+    }
+    return list;
 }
 
 KPluginInfo::List PluginLoader::listAppletInfoForMimeType(const QString &mimeType)

src/plasma/pluginloader.h

@@ -167,8 +167,31 @@ public:
      *                  list containing only applets not specifically
      *                  registered to an application.
      * @return list of applets
+     *
+     * @deprecated use listAppletMetaData. Doesn't support metadata.json packages.
      **/
-    KPluginInfo::List listAppletInfo(const QString &category, const QString &parentApp = QString());
+    PLASMA_DEPRECATED KPluginInfo::List listAppletInfo(const QString &category, const QString &parentApp = QString());
+
+    /**
+     * Returns a list of all known applets.
+     * This may skip applets based on security settings and ExcludeCategories in the application's config.
+     *
+     * @param category Only applets matchin this category will be returned.
+     *                 Useful in conjunction with knownCategories.
+     *                 If "Misc" is passed in, then applets without a
+     *                 Categories= entry are also returned.
+     *                 If an empty string is passed in, all applets are
+     *                 returned.
+     * @param parentApp the application to filter applets on. Uses the
+     *                  X-KDE-ParentApp entry (if any) in the plugin info.
+     *                  The default value of QString() will result in a
+     *                  list containing only applets not specifically
+     *                  registered to an application.
+     * @return list of applets
+     *
+     * @since 5.28
+     **/
+    QList<KPluginMetaData> listAppletMetaData(const QString &category, const QString &parentApp = QString());
 
     /**
      * Returns a list of all known applets associated with a certain mimetype.

src/plasma/private/applet_p.cpp

@@ -57,7 +57,7 @@ AppletPrivate::AppletPrivate(const KPluginMetaData &info, int uniqueID, Applet *
       immutability(Types::Mutable),
       oldImmutability(Types::Mutable),
       appletDescription(info),
-      icon(appletDescription.isValid() ? appletDescription.iconName() : QString()),
+      icon(appletDescription.iconName()),
       mainConfig(0),
       pendingConstraints(Types::NoConstraint),
       script(0),