VCS_INFO_detect_by_dir() { #{{{
    local dirname=$1
    local basedir="." realbasedir

    realbasedir="$(VCS_INFO_realpath ${basedir})"
    while [[ ${realbasedir} != '/' ]]; do
        if [[ -n ${vcs_comm[detect_need_file]} ]] ; then
            [[ -d ${basedir}/${dirname} ]] && \
            [[ -e ${basedir}/${dirname}/${vcs_comm[detect_need_file]} ]] && \
                break
        else
            [[ -d ${basedir}/${dirname} ]] && break
        fi

        basedir=${basedir}/..
        realbasedir="$(VCS_INFO_realpath ${basedir})"
    done

    [[ ${realbasedir} == "/" ]] && return 1
    vcs_comm[basedir]=${realbasedir}
    return 0
}