pacman-db-upgrade: use pacman-style options

* convert dbpath from argument to option
* add --config and --root options
* read dbpath and root from config file
* if root is set but not dbpath, dbpath is set relative to root

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>

scripts/Makefile.am

@@ -54,6 +54,7 @@ endif
 
 #### Taken from the autoconf scripts Makefile.am ####
 edit = sed \
+	-e 's|@rootdir[@]|$(ROOTDIR)|g' \
 	-e 's|@localedir[@]|$(localedir)|g' \
 	-e 's|@sysconfdir[@]|$(sysconfdir)|g' \
 	-e 's|@localstatedir[@]|$(localstatedir)|g' \

scripts/pacman-db-upgrade.sh.in

@@ -25,19 +25,25 @@ export TEXTDOMAINDIR='@localedir@'
 
 declare -r myver='@PACKAGE_VERSION@'
 
-eval $(awk '/DBPath/ {print $1$2$3}' @sysconfdir@/pacman.conf)
-dbroot="${DBPath:-@localstatedir@/lib/pacman/}"
-
-USE_COLOR='y'
-
 m4_include(library/output_format.sh)
 
+m4_include(library/parseopts.sh)
+
 usage() {
 	printf "pacman-db-upgrade (pacman) %s\n" "${myver}"
 	echo
 	printf -- "$(gettext "Upgrade the local pacman database to a newer format")\n"
 	echo
-	printf -- "$(gettext "Usage: %s [--nocolor] [pacman_db_root]")\n" "$0"
+	printf -- "$(gettext "Usage: %s [options]")\n" "$0"
+	echo
+	printf -- "$(gettext "options:")\n"
+	printf -- "$(gettext "  -b, --dbpath <path>  set an alternate database location")\n"
+	printf -- "$(gettext "  -h, --help           show this help message and exit")\n"
+	printf -- "$(gettext "  -r, --root <path>    set an alternate installation root")\n"
+	printf -- "$(gettext "  -V, --version        show version information and exit")\n"
+	printf -- "$(gettext "  --config <path>      set an alternate configuration file")\n"
+	printf -- "$(gettext "  --nocolor            disable colorized output messages")\n"
+	echo
 }
 
 version() {
@@ -58,6 +64,18 @@ die_r() {
 	die "$@"
 }
 
+get_opt_from_config() {
+	local keyname="$1" conffile="$2"
+	local key value
+
+	while IFS=$'= \t' read -r key value _; do
+		if [[ $key = $keyname ]]; then
+			echo "$value"
+			return
+		fi
+	done <"$conffile"
+}
+
 # PROGRAM START
 
 # determine whether we have gettext; make it a no-op if we do not
@@ -67,27 +85,40 @@ if ! type gettext &>/dev/null; then
 	}
 fi
 
-if [[ $1 = "-h" || $1 = "--help" ]]; then
-	usage
-	exit 0
-fi
+USE_COLOR='y'
 
-if [[ $1 = "-V" || $1 = "--version" ]]; then
-	version
-	exit 0
+OPT_SHORT="d:hr:V"
+OPT_LONG=('confg' 'dbpath:' 'help' 'nocolor' 'root:' 'version')
+if ! parseopts "$OPT_SHORT" "${OPT_LONG[@]}" -- "$@"; then
+	exit 1 # E_INVALID_OPTION
 fi
+set -- "${OPTRET[@]}"
+unset OPT_SHORT OPT_LONG OPTRET
 
-if [[ $1 = "--nocolor" ]]; then
-	USE_COLOR='n'
+while true; do
+	case "$1" in
+		--config)     shift; conffile="$1" ;;
+		-d|--dbpath)  shift; dbroot="$1" ;;
+		-r|--root)    shift; pacroot="$1" ;;
+		-h|--help)    usage; exit 0 ;;
+		--nocolor)    USE_COLOR='n' ;;
+		-V|--version) version; exit 0 ;;
+		-- )          shift; break 2 ;;
+	esac
 	shift
-fi
+done
+
+conffile=${conffile:-@sysconfdir@/pacman.conf}
+[[ -z $pacroot ]] && pacroot="$(get_opt_from_config "RootDir" "$conffile")"
+[[ -z $dbroot ]] && dbroot="$(get_opt_from_config "DBPath" "$conffile")"
+
+[[ -z $dbroot && -n $pacroot ]] && dbroot="$pacroot/@localstatedir@/lib/pacman"
+
+[[ -z $pacroot ]] && pacroot="@rootdir@"
+[[ -z $dbroot ]] && dbroot="@localstatedir@/lib/pacman/"
 
 m4_include(library/term_colors.sh)
 
-if [[ -n $1 ]]; then
-	dbroot="$1"
-fi
-
 if [[ ! -d $dbroot ]]; then
 	die "$(gettext "%s does not exist or is not a directory.")" "$dbroot"
 fi