Proposal for a backup/sync interface for MultiMC 5

SyncInterface.h

/*
 * Possible backends:
 * Git: https://projects.kde.org/projects/playground/libs/libqgit2/, http://libgit2.github.com/
 * Dropbox: https://www.dropbox.com/developers/core/docs (HTTP)
 */

class SyncVersion : public BaseVersion
{
public:
    QString identifier;
    QDateTime timestamp;

    QString descriptor()
    {
        return identifier;
    }
    QString name()
    {
        return timestamp.toString("ddd MMM d yyyy HH:mm:ss");
    }
    QString typeString()
    {
        return QString();
    }
};

class EntityBase
{
public:
    enum Type
    {
        InstanceFolder,
        Save,
        Configs
    };
    
    EntityBase(const Type type, const QString &path) : type(type), path(path)
    {
        
    }
    virtual ~EntityBase();
    
    Type type;
    /// What's in here depends on the type. If the type is Save it's the name of a save for example.
    QString path;
    
    virtual EntityBase *getChild(const QString &id) = 0;
};

class SyncInterface : public QObject
{
    Q_OBJECT
public:
    SyncInterface(BaseInstance *instance, QObject *parent = 0) : QObject(parent), m_instance(instance), m_settings(0) {}
    virtual ~SyncInterface() {}
    
    void setSettings(SettingsObject *settings)
    {
        m_settings = settings;
    }
    SettingsObject *getSettings() const
    {
        return m_settings;
    }
    
    virtual QWidget *getConfigWidget() = 0;
    
    void addRootEntity(EntityBase *entity) = 0;
    void removeRootEntity(EntityBase *entity) = 0;
    QList<EntityBase *> getRootEntities() = 0;
    
    /**
     * Used when rolling back files
     */
    virtual BaseVersionList *getVersionList(const EntityBase *entity) = 0;
    
    /// git add/commit/push
    virtual bool push(const EntityBase *entity) = 0;
    /// git checkout <version>
    virtual bool setVersion(const EntityBase *entity, const SyncVersion &version) = 0;
    /// git fetch (+ pull if we are on the latest version)
    virtual bool pull(const EntityBase *entity) = 0;
    
protected:
    BaseInstance *m_instance;
    SettingsObject *m_settings;
};