FolderModel::lessThan()

bool FolderModel::lessThan(const QModelIndex &source_left, const QModelIndex &source_right) const
{
    QFileInfo l_info = fsModel_->fileInfo(source_left);
    QFileInfo r_info = fsModel_->fileInfo(source_right);
    bool ascOrder = (sortOrder_ == Qt::AscendingOrder);

    if(dotFirst_)
    {
        if(l_info.fileName() == ".")
        {
            return ascOrder;
        }
        else if(r_info.fileName() == ".")
        {
            return !ascOrder;
        }
        else if(l_info.fileName() == ".." && r_info.fileName() != ".")
        {
            return ascOrder;
        }
        else if(r_info.fileName() == ".." && l_info.fileName() != ".")
        {
            return !ascOrder;
        }
    }

    if(sortFlags_ & QDir::DirsFirst)
    {
        if(!l_info.isDir() && r_info.isDir())
        {
            return !ascOrder;
        }
        else if(l_info.isDir() && !r_info.isDir())
        {
            return ascOrder;
        }
    }
    else if(sortFlags_ & QDir::DirsLast)
    {
        if(!l_info.isDir() && r_info.isDir())
        {
            return ascOrder;
        }
        else if(l_info.isDir() && !r_info.isDir())
        {
            return !ascOrder;
        }
    }
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