xfconf-query

#!/hint/bash -efu

#
# Bash programmable completion rules for xfconf-query
#

# Copyright (C) 2018 Denis Ollier
#
# This script is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

_xfconf_query()
{
    local cur prev words cword
    _init_completion || return  # requires bash-completion >= 1.90 (2011-11-03)

    #
    # Get full completion context
    #
    local action channel property proptype
    local array create recursive verbose
    local set_count type_count

    local i length
    length=${#words[@]}
    # Skip the last word if it is the one being completed
    ((cword == length - 1)) && [ "${cur}" ] && ((length--))

    for ((i = 0; i < length; i++)); do
        case ${words[i]} in
            '-h'|'--help')    return;;  # No completion for -h/--help
            '-V'|'--version') return;;  # No completion for -V/--version

            # See file xfconf-query/main.c:main() for actions priority order
            '-m'|'--monitor') action='monitor';;
            '-l'|'--list')    [[ ${action} != @('monitor') ]] && action='list';;
            '-r'|'--reset')   [[ ${action} != @('monitor'|'list') ]] && action='reset';;
            '-s'|'--set')     [[ ${action} != @('monitor'|'list'|'reset') ]] && action='set'
                              ((set_count++));;  # Multiple set options are allowed to support arrays
            '-T'|'--toggle')  [[ ${action} != @('monitor'|'list'|'reset'|'set') ]] && action='toggle';;

            '-c'|'--channel')  channel=${words[i+1]};;
            '-p'|'--property') property=${words[i+1]};;
            '-t'|'--type')     proptype+=("${words[i+1]}")
                               ((type_count++));;  # Multiple type options are allowed to support arrays

            '-a'|'--force-array') array=1;;
            '-n'|'--create')      create=1;;
            '-R'|'--recursive')   recursive=1;;
            '-v'|'--verbose')     verbose=1;;
        esac
    done

    #
    # Generate smart completions
    #

    # Non-ambiguous completions
    case ${prev} in
        '-c'|'--channel')
            local channels

            channels=(
              $(LC_ALL=C command xfconf-query --list \
              | { IFS='' read line  # Remove "Channels:" header
                  while IFS='' read line; do printf '%s\n' "${line}"; done })
            )

            COMPREPLY=($(compgen -W '"${channels[@]}"' -- "${cur}"))
            return
        ;;
        '-p'|'--property')
            [ ! "${channel}" ] && return

            local properties

            if [ "${action}" = 'toggle' ]; then
                # Keep only boolean properties for toggle action
                properties=(
                  $(LC_ALL=C command xfconf-query --list --verbose --channel="${channel}" \
                  | while read propname propvalue; do
                        if [[ "${propvalue}" == @('true'|'false') ]]; then
                            printf '%s\n' "${propname}"
                        fi
                    done)
                )
            else
                properties=($(LC_ALL=C command xfconf-query --list --channel="${channel}"))
            fi

            COMPREPLY=($(compgen -W '"${properties[@]}"' -- "${cur}"))
            return
        ;;
        '-s'|'--set')
            case ${proptype[set_count-1]} in
                'bool') COMPREPLY=($(compgen -W '"true" "false"' -- "${cur}"));;
                 # Can't guess wanted value for types other than booleans
            esac
            return
        ;;
        '-t'|'--type')
            local types
            # See file common/xfconf-gvaluefuncs.c:_xfconf_gtype_from_string()
            # for the list of supported types
            types=(
              'string' 'int' 'double' 'bool' 'uint' 'uchar' 'char'
              'uint16' 'int16' 'uint64' 'int64' 'float'
            )
            COMPREPLY=($(compgen -W '"${types[@]}"' -- "${cur}"))
            return
        ;;
    esac

    # Fallback to suggesting possible completions
    local suggests

    case ${action} in
        'list')    ((!verbose)) && suggests=('-v' '--verbose');;

        'reset')   ((!recursive)) && suggests=('-R' '--recursive');;

        'set')     ((!array)) && suggests+=('-s' '--set')
                   ((!array && (set_count <= 1))) && suggests+=('-a' '--force-array')
                   ((!create)) && suggests+=('-n' '--create')
                   ((set_count > type_count)) && suggests+=('-t' '--type')
        ;;

        '')  suggests=('-l' '--list' '-r' '--reset' '-s' '--set' '-T' '--toggle')
             [ ! "${property}" ] && suggests+=('-m' '--monitor')
             ((${#words[@]} == 2)) && suggests+=('-h' '--help' '-V' '--version')
        ;;
    esac

    [ ! "${channel}"  ] && suggests+=('-c' '--channel')
    [ ! "${property}" ] && [ "${channel}" ] && [ "${action}" != 'monitor' ] && suggests+=('-p' '--property')

    COMPREPLY=($(compgen -W '"${suggests[@]}"' -- "${cur}"))
}

complete -F _xfconf_query xfconf-query

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