scripts/library: introduce parseopts

This will replace our current options parser used in pacman-key,
makepkg, and ideally elsewhere. It follows heuristics closer to that of
GNU getopt long (and thus pacman itself), with the exception that it
does not allow for options with optional arguments. Due to the way this
parser will be used, this sort of functionality will not be needed.

Instead of relying on eval+set, options are normalized into an array,
OPTRET, which callers should expect to be populated after returning from
parseopts. This avoids problems with quotes and spaces in arguments,
assuming that the user quotes properly when passing into the
application.

A new test harness for parseopts is added in test/scripts.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>

2 files changed, 161 insertions, 0 deletions

diff --git a/scripts/library/README b/scripts/library/README
index 1e9c962b..f43873f3 100644
--- a/scripts/library/README
+++ b/scripts/library/README
@@ -13,3 +13,23 @@ A getopt replacement to avoids portability issues, in particular the
 lack of long option name support in the default getopt provided by some
 platforms.
 Usage: parse_option $SHORT_OPTS $LONG_OPTS "$@"
+
+parseopts.sh:
+A getopt_long-like parser which portably supports longopts and shortopts
+with some GNU extensions. It does not allow for options with optional
+arguments. For both short and long opts, options requiring an argument
+should be suffixed with a colon. After the first argument containing
+the short opts, any number of valid long opts may be be passed. The end
+of the options delimiter must then be added, followed by the user arguments
+to the calling program.
+
+Reccommended Usage:
+  OPT_SHORT='fb:z'
+  OPT_LONG=('foo' 'bar:' 'baz')
+  if ! parseopts "$OPT_SHORT" "${OPT_LONG[@]}" -- "$@"; then
+    exit 1
+  fi
+  set -- "${OPTRET[@]}"
+Returns:
+  0: parse success
+  1: parse failure (error message supplied)
diff --git a/scripts/library/parseopts.sh b/scripts/library/parseopts.sh
new file mode 100644
index 00000000..11589ce3
--- /dev/null
+++ b/scripts/library/parseopts.sh
@@ -0,0 +1,141 @@
+# getopt-like parser
+parseopts() {
+	local opt= optarg= i= shortopts=$1
+	local -a longopts=() unused_argv=()
+
+	shift
+	while [[ $1 && $1 != '--' ]]; do
+		longopts+=("$1")
+		shift
+	done
+	shift
+
+	longoptmatch() {
+		local o longmatch=()
+		for o in "${longopts[@]}"; do
+			if [[ ${o%:} = "$1" ]]; then
+				longmatch=("$o")
+				break
+			fi
+			[[ ${o%:} = "$1"* ]] && longmatch+=("$o")
+		done
+
+		case ${#longmatch[*]} in
+			1)
+				# success, override with opt and return arg req (0 == none, 1 == required)
+				opt=${longmatch%:}
+				if [[ $longmatch = *: ]]; then
+					return 1
+				else
+					return 0
+				fi ;;
+			0)
+				# fail, no match found
+				return 255 ;;
+			*)
+				# fail, ambiguous match
+				printf "@SCRIPTNAME@: $(gettext "option '%s' is ambiguous; possibilities:")" "--$1"
+				printf " '%s'" "${longmatch[@]%:}"
+				printf '\n'
+				return 254 ;;
+		esac >&2
+	}
+
+	while (( $# )); do
+		case $1 in
+			--) # explicit end of options
+				shift
+				break
+				;;
+			-[!-]*) # short option
+				for (( i = 1; i < ${#1}; i++ )); do
+					opt=${1:i:1}
+
+					# option doesn't exist
+					if [[ $shortopts != *$opt* ]]; then
+						printf "@SCRIPTNAME@: $(gettext "invalid option") -- '%s'\n" "$opt" >&2
+						OPTRET=(--)
+						return 1
+					fi
+
+					OPTRET+=("-$opt")
+					# option requires optarg
+					if [[ $shortopts = *$opt:* ]]; then
+						# if we're not at the end of the option chunk, the rest is the optarg
+						if (( i < ${#1} - 1 )); then
+							OPTRET+=("${1:i+1}")
+							break
+						# if we're at the end, grab the the next positional, if it exists
+						elif (( i == ${#1} - 1 )) && [[ $2 ]]; then
+							OPTRET+=("$2")
+							shift
+							break
+						# parse failure
+						else
+							printf "@SCRIPTNAME@: $(gettext "option requires an argument") -- '%s'\n" "$opt" >&2
+							OPTRET=(--)
+							return 1
+						fi
+					fi
+				done
+				;;
+			--?*=*|--?*) # long option
+				IFS='=' read -r opt optarg <<< "${1#--}"
+				longoptmatch "$opt"
+				case $? in
+					0)
+						# parse failure
+						if [[ $optarg ]]; then
+							printf "@SCRIPTNAME@: $(gettext "option '%s' does not allow an argument")\n" "--$opt" >&2
+							OPTRET=(--)
+							return 1
+						# --longopt
+						else
+							OPTRET+=("--$opt")
+							shift
+							continue 2
+						fi
+						;;
+					1)
+						# --longopt=optarg
+						if [[ $optarg ]]; then
+							OPTRET+=("--$opt" "$optarg")
+							shift
+						# --longopt optarg
+						elif [[ $2 ]]; then
+							OPTRET+=("--$opt" "$2" )
+							shift 2
+						# parse failure
+						else
+							printf "@SCRIPTNAME@: $(gettext "option '%s' requires an argument")\n" "--$opt" >&2
+							OPTRET=(--)
+							return 1
+						fi
+						continue 2
+						;;
+					254)
+						# ambiguous option -- error was reported for us by longoptmatch()
+						OPTRET=(--)
+						return 1
+						;;
+					255)
+						# parse failure
+						printf "@SCRIPTNAME@: $(gettext "invalid option") '--%s'\n" "$opt" >&2
+						OPTRET=(--)
+						return 1
+						;;
+				esac
+				;;
+			*) # non-option arg encountered, add it as a parameter
+				unused_argv+=("$1")
+				;;
+		esac
+		shift
+	done
+
+	# add end-of-opt terminator and any leftover positional parameters
+	OPTRET+=('--' "${unused_argv[@]}" "$@")
+	unset longoptmatch
+
+	return 0
+}