systemd/shell-completion/bash/resolvectl

# resolvectl(1) completion                                  -*- shell-script -*-
# SPDX-License-Identifier: LGPL-2.1+
#
# This file is part of systemd.
#
# Copyright 2018 Yu Watanabe
#
# 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(){
        { cd /sys/class/net && echo *; } | \
        while read -d' ' -r name; 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'
               [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'
        )
        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]} ${VERBS[DNSSEC]}; then
                for ((i++; i < COMP_CWORD; i++)); do
                        if __contains_word "${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

                else
                        comps=''
                fi
        fi

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

complete -F _resolvectl resolvectl