[libcalamares] Allow QML ViewSteps to expose a config object

src/libcalamaresui/viewpages/QmlViewStep.cpp

@@ -29,6 +29,7 @@
 #include "widgets/WaitingWidget.h"
 
 #include <QQmlComponent>
+#include <QQmlContext>
 #include <QQmlEngine>
 #include <QQuickItem>
 #include <QQuickWidget>
@@ -209,6 +210,11 @@ QmlViewStep::loadComplete()
             // It is marked \internal in the Qt sources, but does exactly
             // what is needed: sets up visual parent by replacing the root
             // item, and handling resizes.
+            QObject* config = this->getConfig();
+            if ( config )
+            {
+                m_qmlWidget->engine()->rootContext()->setContextProperty( "config", config );
+            }
             m_qmlWidget->setContent( QUrl( m_qmlFileName ), m_qmlComponent, m_qmlObject );
             showQml();
         }
@@ -336,4 +342,10 @@ QmlViewStep::showFailedQml()
     m_spinner->setText( prettyName() + ' ' + tr( "Loading failed." ) );
 }
 
+QObject*
+QmlViewStep::getConfig()
+{
+    return nullptr;
+}
+
 }  // namespace Calamares

src/libcalamaresui/viewpages/QmlViewStep.h

@@ -76,6 +76,18 @@ public:
     /// @brief Configure search paths; subclasses should call this as well
     virtual void setConfigurationMap( const QVariantMap& configurationMap ) override;
 
+protected:
+    /** @brief Gets a pointer to the Config of this view step
+     *
+     * Parts of the configuration of the viewstep can be passed to QML
+     * by placing them in a QObject (as properties). The default
+     * implementation returns nullptr, for no-config.
+     *
+     * Ownership of the config object remains with the ViewStep; it is possible
+     * to return a pointer to a member variable.
+     */
+    virtual QObject* getConfig();
+
 private Q_SLOTS:
     void loadComplete();
 

src/modules/welcomeq/WelcomeQmlViewStep.cpp

@@ -194,3 +194,9 @@ WelcomeQmlViewStep::setCountry( const QString& countryCode, CalamaresUtils::GeoI
         }
     }
 }
+
+QObject*
+WelcomeQmlViewStep::getConfig()
+{
+    return &m_config;
+}

src/modules/welcomeq/WelcomeQmlViewStep.h

@@ -61,6 +61,9 @@ public:
 
     Calamares::RequirementsList checkRequirements() override;
 
+protected:
+    QObject* getConfig() override;
+
 private:
     // TODO: a generic QML viewstep should return a config object from a method
     Config m_config;