[plasmalnf] Prepare a new model

- start a model for available themes, to replace the list held
  by the widget which just duplicates information.
- move preselected theme to Config.

src/modules/plasmalnf/Config.cpp

@@ -15,8 +15,99 @@
 #include "utils/Logger.h"
 #include "utils/Variant.h"
 
+#ifdef WITH_KCONFIG
+#include <KConfigGroup>
+#include <KSharedConfig>
+#endif
+
+#include <KPackage/Package>
+#include <KPackage/PackageLoader>
+
+#include <QAbstractListModel>
+#include <QList>
+
+class ThemesModel : public QAbstractListModel
+{
+    Q_OBJECT
+
+public:
+    enum
+    {
+        LabelRole = Qt::DisplayRole,
+        KeyRole = Qt::UserRole
+    };
+
+    explicit ThemesModel( QObject* parent );
+
+    int rowCount( const QModelIndex& = QModelIndex() ) const override;
+    QVariant data( const QModelIndex& index, int role ) const override;
+
+    QHash< int, QByteArray > roleNames() const override;
+
+private:
+    QList< KPluginMetaData > m_themes;
+};
+
+ThemesModel::ThemesModel( QObject* parent )
+    : QAbstractListModel( parent )
+    , m_themes( KPackage::PackageLoader::self()->listPackages( "Plasma/LookAndFeel" ) )
+{
+}
+
+int
+ThemesModel::rowCount( const QModelIndex& ) const
+{
+    return m_themes.count();
+}
+
+QVariant
+ThemesModel::data( const QModelIndex& index, int role ) const
+{
+    if ( !index.isValid() )
+    {
+        return QVariant();
+    }
+    if ( index.row() < 0 || index.row() >= m_themes.count() )
+    {
+        return QVariant();
+    }
+
+    const auto& item = m_themes.at( index.row() );
+    switch ( role )
+    {
+    case LabelRole:
+        return item.name();
+    case KeyRole:
+        return item.pluginId();
+    default:
+        return QVariant();
+    }
+    __builtin_unreachable();
+}
+
+QHash< int, QByteArray >
+ThemesModel::roleNames() const
+{
+    return { { LabelRole, "label" }, { KeyRole, "key" } };
+}
+
+
+static QString
+currentPlasmaTheme()
+{
+#ifdef WITH_KCONFIG
+    KConfigGroup cg( KSharedConfig::openConfig( QStringLiteral( "kdeglobals" ) ), "KDE" );
+    return cg.readEntry( "LookAndFeelPackage", QString() );
+#else
+    cWarning() << "No KConfig support, cannot determine Plasma theme.";
+    return QString();
+#endif
+}
+
+
 Config::Config( QObject* parent )
     : QObject( parent )
+    , m_themeModel( new ThemesModel( this ) )
 {
 }
 
@@ -31,6 +122,13 @@ Config::setConfigurationMap( const QVariantMap& configurationMap )
     }
 
     m_liveUser = CalamaresUtils::getString( configurationMap, "liveuser" );
+
+    QString preselect = CalamaresUtils::getString( configurationMap, "preselect" );
+    if ( preselect == QStringLiteral( "*" ) )
+    {
+        preselect = currentPlasmaTheme();
+    }
+    m_preselectThemeId = preselect;
 }
 
 Calamares::JobList
@@ -92,3 +190,7 @@ Config::setTheme( const QString& id )
     }
     emit themeChanged( id );
 }
+
+#include "utils/moc-warnings.h"
+
+#include "Config.moc"

src/modules/plasmalnf/Config.h

@@ -14,15 +14,19 @@
 
 #include <QObject>
 
+class QAbstractItemModel;
+
 class Config : public QObject
 {
     Q_OBJECT
 
+    Q_PROPERTY( QString preselectedTheme READ preselectedTheme CONSTANT )
     Q_PROPERTY( QString theme READ theme WRITE setTheme NOTIFY themeChanged )
+    Q_PROPERTY( QAbstractItemModel* themeModel READ themeModel CONSTANT )
 
 public:
     Config( QObject* parent = nullptr );
-    virtual ~Config() override = default;
+    virtual ~Config() override = default;  // QObject cleans up the model pointer
 
     void setConfigurationMap( const QVariantMap& );
     Calamares::JobList createJobs() const;
@@ -42,6 +46,17 @@ public:
      */
     QString theme() const { return m_themeId; }
 
+    /** @brief The theme we start with
+     *
+     * This can be configured, or is taken from the live environment
+     * if the environment is (also) KDE Plasma.
+     */
+    QString preselectedTheme() const { return m_preselectThemeId; }
+
+    /** @brief The (list) model of available themes.
+     */
+    QAbstractItemModel* themeModel() const { return m_themeModel; }
+
 public slots:
     void setTheme( const QString& id );
 
@@ -52,7 +67,10 @@ private:
     QString m_lnfPath;  // Path to the lnf tool
     QString m_liveUser;  // Name of the live user (for OEM mode)
 
+    QString m_preselectThemeId;
     QString m_themeId;  // Id of selected theme
+
+    QAbstractItemModel* m_themeModel = nullptr;
 };
 
 #endif

src/modules/plasmalnf/PlasmaLnfViewStep.cpp

@@ -15,28 +15,10 @@
 #include "utils/Logger.h"
 #include "utils/Variant.h"
 
-#include <QProcess>
 #include <QVariantMap>
 
-#ifdef WITH_KCONFIG
-#include <KConfigGroup>
-#include <KSharedConfig>
-#endif
-
 CALAMARES_PLUGIN_FACTORY_DEFINITION( PlasmaLnfViewStepFactory, registerPlugin< PlasmaLnfViewStep >(); )
 
-static QString
-currentPlasmaTheme()
-{
-#ifdef WITH_KCONFIG
-    KConfigGroup cg( KSharedConfig::openConfig( QStringLiteral( "kdeglobals" ) ), "KDE" );
-    return cg.readEntry( "LookAndFeelPackage", QString() );
-#else
-    cWarning() << "No KConfig support, cannot determine Plasma theme.";
-    return QString();
-#endif
-}
-
 PlasmaLnfViewStep::PlasmaLnfViewStep( QObject* parent )
     : Calamares::ViewStep( parent )
     , m_config( new Config( this ) )
@@ -117,16 +99,7 @@ PlasmaLnfViewStep::setConfigurationMap( const QVariantMap& configurationMap )
     m_config->setConfigurationMap( configurationMap );
 
     m_widget->setLnfPath( m_config->lnfToolPath() );
-
-    QString preselect = CalamaresUtils::getString( configurationMap, "preselect" );
-    if ( preselect == QStringLiteral( "*" ) )
-    {
-        preselect = currentPlasmaTheme();
-    }
-    if ( !preselect.isEmpty() )
-    {
-        m_widget->setPreselect( preselect );
-    }
+    m_widget->setPreselect( m_config->preselectedTheme() );
 
     bool showAll = CalamaresUtils::getBool( configurationMap, "showAll", false );