eos-pkgbuild-setup/ShowPkgbuildValue

#!/bin/bash

# NOTE: this implementation is considered experimental and isn't fit for production!

_PBV_Help() {
    cat <<EOF >&2
$_PBV_progname shows the value of one or more named variables in the PKGBUILD file.
The PKGBUILD file is expected to reside in the current working directory.

Usage:    $_PBV_progname [options] variable-name(s)
Options:  -h, --help               This help.
          --combined               Show values concatenated as "v1-v2-v3" and so on.
See also: man PKGBUILD

Examples:
   $ ShowPkgbuildValue pkgrel               # a non-array variable
     1
   $ ShowPkgbuildValue depends              # an array variable
     curl
     xdg-utils
   $ ShowPkgbuildValue pkgrel depends       # non-array and array variables
     pkgrel:
         1
     depends:
         curl
         xdg-utils
EOF
}

_PBV_DIE()  { echo -e "==> $_PBV_progname: error: $1" >&2; exit 1; }
_PBV_WARN() { echo -e "==> $_PBV_progname: warning: $1" >&2; }

_PBV_ShowValue() {
    local _PBV_vararg="$1"

    if [ "$_PBV_vararg" ] ; then
        local _PBV_varname="$_PBV_vararg"
    else
        local -n _PBV_varname="${_PBV_VAR}"
    fi
    if [ "${_PBV_varname[0]}" ] ; then
        case "$_PBV_combined" in
            no)
                case "$_PBV_varcount" in
                    0) ;;
                    1) printf "%s\n" "${_PBV_varname[@]}" ;;
                    *) echo "$_PBV_VAR:"; printf "    %s\n" "${_PBV_varname[@]}" ;;
                esac
                ;;
            yes)
                case "${#_PBV_varname[@]}" in
                    0) ;;
                    1)  if [ "$_PBV_combined_val" ] ; then
                            _PBV_combined_val+="-${_PBV_varname[0]}"
                        else
                            _PBV_combined_val="${_PBV_varname[0]}"
                        fi
                        ;;
                    *)
                        _PBV_DIE "sorry, don't know how to return a combines value from $_PBV_VAR that includes ${#_PBV_varname[*]} members"
                        ;;
                esac
                ;;
        esac
    fi
}

_PBV_Show_pkgver() {
    # Handle pkgver() if it exists.

    local _PBV_pkgver="$pkgver"

    if declare -F pkgver &>/dev/null ; then
        local _PBV_log _PBV_code=0
        _PBV_log=$(mktemp)
        chmod go-rwx "$_PBV_log"
        makepkg --skipinteg -od &> "$_PBV_log" || _PBV_code=$?
        [ "$_PBV_code" -eq 0 ] || _PBV_DIE "$pkgname: pkgver: makepkg failed, exit code $_PBV_code.\n    See file $_PBV_log for the details."
        rm -f "$_PBV_log"
        _PBV_pkgver="$(grep ^pkgver= ./PKGBUILD)"
        [ "$_PBV_pkgver" ]                       || _PBV_DIE "$pkgname: 'pkgver' is not set in $PWD/PKGBUILD!?"
        [ "$(echo "$_PBV_pkgver" | wc -l)" = 1 ] || _PBV_DIE "$pkgname: failed to extract the value of 'pkgver' from $PWD/PKGBUILD."
        _PBV_pkgver=${_PBV_pkgver#*=}
        _PBV_pkgver=${_PBV_pkgver%%[$'\t' ]*}
        _PBV_pkgver=${_PBV_pkgver//[\'\"]/}
    fi
    _PBV_ShowValue "$_PBV_pkgver"
}

_PBV_GetPkgbuildFieldValue() {
    local _PBV_VAR _PBV_VARS=("$@")
    local -r _PBV_varcount=${#_PBV_VARS[@]}
    local _PBV_combined_val=""

    source ./PKGBUILD || _PBV_DIE "$PWD/PKGBUILD not found or is not readable."

    for _PBV_VAR in "$@" ; do
        # shellcheck disable=2154

        case "$_PBV_VAR" in
            # arrays
            arch |\
            b2sums | b2sums_* |\
            backup |\
            changelog |\
            checkdepends | checkdepends_* |\
            cksums | cksums_* |\
            conflicts | conflicts_* |\
            depends | depends_* |\
            epoch |\
            groups |\
            install |\
            license |\
            makedepends | makedepends_* |\
            md5ums | md5sums_* |\
            noextract |\
            optdepends | optdepends_* |\
            options | options_* |\
            pkgdesc |\
            pkgname |\
            pkgrel |\
            provides | provides_* |\
            replaces | replaces_* |\
            sha1sums | sha1sums_* |\
            sha224sums | sha224sums_* |\
            sha256sums | sha256sums_* |\
            sha384sums | sha384sums_* |\
            sha512sums | sha512sums_* |\
            "source" | source_* |\
            url |\
            validpgpkeys |\
            xdata)
                _PBV_ShowValue ;;
            pkgver)
                _PBV_Show_pkgver ;;
            *)
                _PBV_WARN "variable name '$_PBV_VAR' is not supported"
                ;;
        esac
    done
}

_PBV_Main() {
    local -r _PBV_progname=${0##*/}
    local _PBV_arg
    local _PBV_combined=no
    local _PBV_variables=()

    for _PBV_arg in "$@" ; do
        case "$_PBV_arg" in
            -h | --help)            _PBV_Help; exit 0 ;;
            --combined)             _PBV_combined=yes ;;
            --list-supported-names) _PBV_ListSupportedNames; exit 0 ;;
            --options)              echo "-h --help --combined --list-supported-names --options"; exit 0 ;;
            -*)                     ;;
            *)                      _PBV_variables+=("$_PBV_arg") ;;
        esac
    done
    _PBV_GetPkgbuildFieldValue "${_PBV_variables[@]}"
}

_PBV_AllArchs() {
    local _PBV_name="$1"
    echo "${_PBV_name}"{,_x86_64,_arm,_armv7h,_aarch64}
}

_PBV_ListSupportedNames() {
    # shellcheck disable=2207
    local _PBV_varnames=(
        arch
        $(_PBV_AllArchs b2sums)
        backup
        changelog
        $(_PBV_AllArchs checkdepends)
        $(_PBV_AllArchs cksums)
        $(_PBV_AllArchs conflicts)
        $(_PBV_AllArchs depends)
        epoch
        groups
        install
        license
        $(_PBV_AllArchs makedepends)
        $(_PBV_AllArchs md5ums)
        noextract
        $(_PBV_AllArchs optdepends)
        $(_PBV_AllArchs options)
        pkgdesc
        pkgname
        pkgrel
        pkgver
        $(_PBV_AllArchs provides)
        $(_PBV_AllArchs replaces)
        $(_PBV_AllArchs sha1sums)
        $(_PBV_AllArchs sha224sums)
        $(_PBV_AllArchs sha256sums)
        $(_PBV_AllArchs sha384sums)
        $(_PBV_AllArchs sha512sums)
        $(_PBV_AllArchs source)
        url
        validpgpkeys
        xdata
    )
    echo "${_PBV_varnames[*]}"
}

_PBV_Main "$@"