systemd/shell-completion/bash/resolvectl

# resolvectl(1) completion                                  -*- shell-script -*-
# SPDX-License-Identifier: LGPL-2.1+
#
# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# systemd is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with systemd; If not, see <http://www.gnu.org/licenses/>.

__contains_word () {
    local w word=$1; shift
    for w in "$@"; do
        [[ $w = "$word" ]] && return
    done
}

__get_interfaces(){
    local name
    for name in $(cd /sys/class/net && ls); do
        [[ "$name" != "lo" ]] && echo "$name"
    done
}

_resolvectl() {
    local i comps verb name
    local cur=${COMP_WORDS[COMP_CWORD]} prev=${COMP_WORDS[COMP_CWORD-1]}
    local -A OPTS=(
        [STANDALONE]='-h --help --version --no-pager -4 -6
                      --service-address=no --service-txt=no
                      --cname=no --search=no --legend=no'
        [ARG]='-i --interface -p --protocol -t --type -c --class --raw'
    )
    local -A VERBS=(
        [DOMAIN]='query service openpgp'
        [FAMILY]='tlsa'
        [STATUS]='status'
        [LINK]='revert dns domain nta'
        [RESOLVE]='llmnr mdns'
        [DNSSEC]='dnssec'
        [DNSOVERTLS]='dnsovertls'
        [STANDALONE]='statistics reset-statistics flush-caches reset-server-features'
    )
    local -A ARGS=(
        [FAMILY]='tcp udp sctp'
        [RESOLVE]='yes no resolve'
        [DNSSEC]='yes no allow-downgrade'
        [DNSOVERTLS]='yes no opportunistic'
    )
    local interfaces=$( __get_interfaces )

    if __contains_word "$prev" ${OPTS[ARG]}; then
        case $prev in
            --interface|-i)
                comps="$interfaces"
                ;;
            --protocol|-p|--type|-t|--class|-c)
                comps=$( resolvectl --legend=no "$prev" help; echo help )
                ;;
            --raw)
                comps="payload packet"
                ;;
        esac
        COMPREPLY=( $(compgen -W '$comps' -- "$cur") )
        return 0
    fi

    if [[ "$cur" = -* ]]; then
        COMPREPLY=( $(compgen -W '${OPTS[*]}' -- "$cur") )
        return 0
    fi

    for ((i=0; i < COMP_CWORD; i++)); do
        if __contains_word "${COMP_WORDS[i]}" ${VERBS[*]} &&
                ! __contains_word "${COMP_WORDS[i-1]}" ${OPTS[ARG]}; then
            verb=${COMP_WORDS[i]}
            break
        fi
    done

    if [[ -z $verb ]]; then
        comps="${VERBS[*]}"

    elif __contains_word "$verb" ${VERBS[STANDALONE]} ${VERBS[DOMAIN]}; then
        comps=''

    elif __contains_word "$verb" ${VERBS[STATUS]}; then
        comps="$interfaces"

    elif __contains_word "$verb" ${VERBS[FAMILY]}; then
        for ((i++; i < COMP_CWORD; i++)); do
            if __contains_word "${COMP_WORDS[i]}" ${ARGS[FAMILY]} &&
                    ! __contains_word "${COMP_WORDS[i-1]}" ${OPTS[ARG]}; then
                name=${COMP_WORDS[i]}
                break;
            fi
        done
        if [[ -z $name ]]; then
            comps=${ARGS[FAMILY]}
        else
            comps=""
        fi

    elif __contains_word "$verb" ${VERBS[LINK]} ${VERBS[RESOLVE]} ${VERBS[DNSSEC]} ${VERBS[DNSOVERTLS]}; then
        for ((i++; i < COMP_CWORD; i++)); do
            if __contains_word "${COMP_WORDS[i]}" $interfaces &&
                    ! __contains_word "${COMP_WORDS[i-1]}" ${OPTS[ARG]}; then
                name=${COMP_WORDS[i]}
                break;
            fi
        done

        if [[ -z $name ]]; then
            comps="$interfaces"

        elif __contains_word "$verb" ${VERBS[RESOLVE]}; then
            name=
            for ((i++; i < COMP_CWORD; i++)); do
                if __contains_word "${COMP_WORDS[i]}" ${ARGS[RESOLVE]} &&
                        ! __contains_word "${COMP_WORDS[i-1]}" ${OPTS[ARG]}; then
                    name=${COMP_WORDS[i]}
                    break;
                fi
            done

            if [[ -z $name ]]; then
                comps=${ARGS[RESOLVE]}
            else
                comps=''
            fi

        elif __contains_word "$verb" ${VERBS[DNSSEC]}; then
            name=
            for ((i++; i < COMP_CWORD; i++)); do
                if __contains_word "${COMP_WORDS[i]}" ${ARGS[DNSSEC]} &&
                        ! __contains_word "${COMP_WORDS[i-1]}" ${OPTS[ARG]}; then
                    name=${COMP_WORDS[i]}
                    break;
                fi
            done

            if [[ -z $name ]]; then
                comps=${ARGS[DNSSEC]}
            else
                comps=''
            fi

        elif __contains_word "$verb" ${VERBS[DNSOVERTLS]}; then
            name=
            for ((i++; i < COMP_CWORD; i++)); do
                if __contains_word "${COMP_WORDS[i]}" ${ARGS[DNSOVERTLS]} &&
                        ! __contains_word "${COMP_WORDS[i-1]}" ${OPTS[ARG]}; then
                    name=${COMP_WORDS[i]}
                    break;
                fi
            done

            if [[ -z $name ]]; then
                comps=${ARGS[DNSOVERTLS]}
            else
                comps=''
            fi

        else
            comps=''
        fi
    fi

    COMPREPLY=( $(compgen -W '$comps' -- "$cur") )
    return 0
}

complete -F _resolvectl resolvectl