libredbdiff: Improve option parsing. Add missing info to usage().

There are a couple of pointless `if true`s in there to avoid whitespace
change.

1 files changed, 55 insertions, 26 deletions

diff --git a/src/abslibre-tools/libredbdiff b/src/abslibre-tools/libredbdiff
index 5ef1029..8bcc6d9 100755
--- a/src/abslibre-tools/libredbdiff
+++ b/src/abslibre-tools/libredbdiff
@@ -150,18 +150,6 @@ initialize() {
 	fi
 }
 
-repo_test() {
-	for repo in "${repos[@]}" ; do
-		if [[ "$repo" == "$1" ]] ; then
-			found=1
-			return 0
-		fi
-	done
-	if [[ "$found" != 1 ]] ; then
-		die "The specified Parabola repo \"%s\" cannot be compared.  It's not in the list of repos in the configuration variable \"repos\"." "$1"
-	fi
-}
-
 compare_pkgs() {
 	local cmp
 	if [[ -n "${ver_arch[$pkgname]}" ]] ; then
@@ -212,7 +200,9 @@ print_cmp() {
 }
 
 usage() {
-	print "Usage: %q [-n|-h]" "$cmd"
+	print "Usage: sudo %q" "$cmd"
+	print "   or: %q -n [REPO]" "$cmd"
+	print "   or: %q -h" "$cmd"
 	print 'Show packages that need to be updated from Arch repositories.'
 	echo
 	prose "Compares packages in Parabola repositories.  Packages from
@@ -225,6 +215,12 @@ usage() {
 	       flag to not download anything, but to compare already downloaded
 	       files."
 	echo
+	prose "In the compare mode (if the \`-n\` flag is given), by default it
+	       will iterate over each of the configured repositories, prefixing
+	       each section with a line in the format \`[REPO]\`.  However, if a
+	       REPO is specified on the command line, it scan for packages only
+	       in that repository, and no \`[REPO]\` line will be printed."
+	echo
 	print 'Options:'
 	flag '-n' "Don't update anything, just compare already downloaded files."
 	flag '-h' 'Show this message'
@@ -242,28 +238,57 @@ usage() {
 }
 
 main() {
-	local UPDATE=1
-	local arg
-	local repo_arg
-
-	for arg in "$@"; do
+	local args arg mode=update badargs=false
+	args="$(getopt -n "$cmd" -o nh -l noupdate,help -- "$@")" || badargs=true
+	eval "set -- $args"
+	while [[ $# -gt 0 ]]; do
+		arg=$1
+		shift
 		case "$arg" in
 			-n|--noupdate)
-				UPDATE=0
+				mode=compare
 				;;
 			-h|--help)
 				usage
 				return 0
 				;;
-			*)
-				repo_test "$arg"
-				repo_arg="$arg"
+			--)
 				break
 				;;
 		esac
 	done
+	if $badargs; then
+		usage >&2
+		return 2
+	fi
+
+	case $mode in
+		update)
+			if [[ $# -gt 0 ]]; then
+				print "%s: found non-flag arguments; a repo list may only be specified with the -n flag: %s" "$cmd" "$*" >&2
+				usage >&2
+				return 2
+			fi
+			main_update
+			;;
+		compare)
+			if [[ $# -gt 1 ]]; then
+				print "%s: found too many non-flag arguments; only one repo may be specified: %s" "$cmd" "$*" >&2
+				usage >&2
+				return 2
+			fi
+			if [[ $# = 1 ]]; then
+				if ! in_array "$1" "${repos[@]}"; then
+					die "The specified Parabola repo \"%s\" cannot be compared.  It's not in the list of repos in the configuration variable \"repos\"." "$1"
+				fi
+			fi
+			main_compare "$@"
+			;;
+	esac
+}
 
-	if (( UPDATE )) ; then
+main_update() {
+	if true; then
 		if [[ $EUID != 0 ]]; then
 			die "To initialize %s or update %s pacman databases, %s must be run as root (without arguments).  Nothing done." \
 				"$name" \
@@ -305,7 +330,11 @@ main() {
 		msg "%s pacman databases are updated.  %s is ready.  Run %q -n to print results." \
 		    "$name" "$name" "$cmd"
 		return 0
-	else
+	fi
+}
+
+main_compare() {
+	if true; then
 		check_vars libredbdiff statedir repos || exit 1
 
 		filenotfound "$dbpath_prbl/sync/libre.db"
@@ -332,8 +361,8 @@ main() {
 			die "expac command to get Parabola package data has failed.  Exiting."
 		chmod 777 "$prbl_packages_tmp"
 
-		if [[ -n "$repo_arg" ]] ; then
-			print_cmp "$repo_arg"
+		if [[ $# == 1 ]]; then
+			print_cmp "$1"
 		else
 			for repo in "${repos[@]}" ; do
 				echo "[$repo]"