+// migration / backend selection
+bool Core::selectBackend(const QString &backend)
+{
+ // reregister all storage backends
+ registerStorageBackends();
+ auto storage = storageBackend(backend);
+ if (!storage) {
+ QStringList backends;
+ std::transform(_registeredStorageBackends.begin(), _registeredStorageBackends.end(),
+ std::back_inserter(backends), [](const DeferredSharedPtr<Storage>& backend) {
+ return backend->displayName();
+ });
+ quWarning() << qPrintable(tr("Unsupported storage backend: %1").arg(backend));
+ quWarning() << qPrintable(tr("Supported backends are:")) << qPrintable(backends.join(", "));
+ return false;
+ }
+
+ QVariantMap settings = promptForSettings(storage.get());
+
+ Storage::State storageState = storage->init(settings);
+ switch (storageState) {
+ case Storage::IsReady:
+ if (!saveBackendSettings(backend, settings)) {
+ qCritical() << qPrintable(QString("Could not save backend settings, probably a permission problem."));
+ }
+ quWarning() << qPrintable(tr("Switched storage backend to: %1").arg(backend));
+ quWarning() << qPrintable(tr("Backend already initialized. Skipping Migration..."));
+ return true;
+ case Storage::NotAvailable:
+ qCritical() << qPrintable(tr("Storage backend is not available: %1").arg(backend));
+ return false;
+ case Storage::NeedsSetup:
+ if (!storage->setup(settings)) {
+ quWarning() << qPrintable(tr("Unable to setup storage backend: %1").arg(backend));
+ return false;
+ }
+
+ if (storage->init(settings) != Storage::IsReady) {
+ quWarning() << qPrintable(tr("Unable to initialize storage backend: %1").arg(backend));
+ return false;
+ }
+
+ if (!saveBackendSettings(backend, settings)) {
+ qCritical() << qPrintable(QString("Could not save backend settings, probably a permission problem."));
+ }
+ quWarning() << qPrintable(tr("Switched storage backend to: %1").arg(backend));
+ break;
+ }
+
+ // let's see if we have a current storage object we can migrate from
+ auto reader = getMigrationReader(_storage.get());
+ auto writer = getMigrationWriter(storage.get());
+ if (reader && writer) {
+ qDebug() << qPrintable(tr("Migrating storage backend %1 to %2...").arg(_storage->displayName(), storage->displayName()));
+ _storage.reset();
+ storage.reset();
+ if (reader->migrateTo(writer.get())) {
+ qDebug() << "Migration finished!";
+ qDebug() << qPrintable(tr("Migration finished!"));
+ if (!saveBackendSettings(backend, settings)) {
+ qCritical() << qPrintable(QString("Could not save backend settings, probably a permission problem."));
+ return false;
+ }
+ return true;
+ }
+ quWarning() << qPrintable(tr("Unable to migrate storage backend! (No migration writer for %1)").arg(backend));
+ return false;
+ }