genkernel.bash

# genkernel (8) completion
# Copyright 2006 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# Written by Aron Griffis <agriffis@gentoo.org>

_genkernel()
{
    declare cur prev genkernel_help actions params
    COMPREPLY=()
    cur=${COMP_WORDS[COMP_CWORD]}
    prev=${COMP_WORDS[COMP_CWORD-1]}

    # extract initial list of params/actions from genkernel --help
    genkernel_help=$(command genkernel --help)
    actions=( $(<<<"$genkernel_help" sed -n \
        '/^Available Actions:/,/^$/s/^[[:space:]]\+\([^[:space:]]\+\).*/\1/p') )
    params=( $(<<<"$genkernel_help" egrep -oe '--[^[:space:]]{2,}') )

    # attempt to complete the current parameter based on the list
    COMPREPLY=($(compgen -W "${params[*]/=*/=} ${actions[*]}" -- "$cur"))

    # if we don't have a rhs to complete
    if [[ ${#COMPREPLY[@]} -gt 1 ]]; then
        return
    elif [[ ${#COMPREPLY[@]} -eq 0 && $cur != --*=* ]]; then
        return
    elif [[ ${#COMPREPLY[@]} -eq 1 && $COMPREPLY != --*= ]]; then
        # using nospace completion, add an explicit space
        COMPREPLY="${COMPREPLY} "
        return
    fi

    # we have a unique lhs and need to complete the rhs
    declare args lhs rhs
    if [[ ${#COMPREPLY[@]} -eq 1 ]]; then
        lhs=$COMPREPLY
    else
        lhs=${cur%%=*}=
        rhs=${cur#*=}
    fi

    # genkernel's help gives clues as to what belongs on the rhs.
    # extract the clue for the current parameter
    args=" ${params[*]} "
    args="${args##* $lhs}"
    args="${args%% *}"

    # generate a list of completions for the argument; this replaces args with
    # an array of results
    args=( $(case $args in
        ('<0-5>') compgen -W "$(echo {1..5})" -- "$rhs" ;;
        ('<outfile>'|'<file>') compgen -A file -o plusdirs -- "$rhs" ;;
        ('<dir>') compgen -A directory -S / -- "$rhs" ;;
        ('<tbz2>') compgen -G '*.tbz2' -G '*.tar.bz2' -o plusdirs -- "$rhs" ;;
        (*) compgen -o bashdefault -- "$rhs" ;; # punt
    esac) )

    # we're using nospace completion to prevent spaces after paths that aren't
    # "done" yet.  So do some hacking to the args to add spaces after
    # non-directories.
    declare slash=/
    args=( "${args[@]/%/ }" )  # add space to all
    args=( "${args[@]/%$slash /$slash}" )  # remove space from dirs

    # recreate COMPREPLY
    if [[ $cur == "$lhs"* ]]; then
        COMPREPLY=( "${args[@]}" )
    elif [[ ${#args[@]} -gt 0 ]]; then
        COMPREPLY=( "${args[@]/#/$lhs}" )
    fi
}

complete -o nospace -F _genkernel genkernel