From b14d0b56dd24c705130e76d6f290ee87c1ffe339 Mon Sep 17 00:00:00 2001
From: Patrick McDermott <patrick.mcdermott@libiquity.com>
Date: Tue, 12 Mar 2019 19:29:58 -0400
Subject: ob_parse_control(): Rewrite field checking

Get rid of the echo and sed pipeline and use case constructs instead of
"[" commands with "${parameter%word}" expansions.

The new logic also will only report duplicate unknown fields once.
---
diff --git a/lib/control.sh b/lib/control.sh
index 48b71fa..b99a05c 100644
--- a/lib/control.sh
+++ b/lib/control.sh
@@ -75,7 +75,6 @@ ob_parse_control()
 	local req_fields=
 	local opt_fields=
 	local check_fields=
-	local all_fields=
 	local got_fields=
 	local line_nr=
 	local line=
@@ -91,10 +90,9 @@ ob_parse_control()
 		file="${1}"
 		field_cb="${2}"
 		user_data="${3}"
-		req_fields="${4}"
-		opt_fields="${5}"
+		req_fields=" ${4} "
+		opt_fields=" ${5} "
 		check_fields='true'
-		all_fields=" ${req_fields} ${opt_fields} "
 	else
 		return 125
 	fi
@@ -127,26 +125,31 @@ ob_parse_control()
 						'control_bad_nv'
 					continue
 				fi
-				if ${check_fields}; then
-					if [ "${all_fields% ${name} *}" = \
-							"${all_fields}" ]; then
-						# Unknown field.
-						_ob_parse_control_error \
-							"${file}" "${line_nr}" \
-							'control_unknown_field' "${name}"
-					else
-						# Remove field from list of required fields.
-						req_fields="$(echo "${req_fields}" | \
-							sed "s/${name}//")"
-					fi
-				fi
-				if [ "${got_fields% ${name} *}" != \
-						"${got_fields}" ]; then
+				case "${got_fields}" in *" ${name} "*)
 					# Duplicate field.
-					_ob_parse_control_error "${file}" "${line_nr}" \
-						'control_duplicate_field' "${name}"
-				else
-					got_fields="${got_fields}${name} "
+					_ob_parse_control_error \
+						"${file}" "${line_nr}" \
+						'control_duplicate_field' \
+						"${name}"
+					continue
+				esac
+				got_fields="${got_fields}${name} "
+				case "${req_fields}" in *" ${name} "*)
+					# Required field: remove from list.
+					req_fields="${req_fields% ${name} *}$(:\
+						) ${req#* ${field} }"
+					continue
+				esac
+				if ${check_fields}; then
+					case "${opt_fields}" in *" ${name} "*)
+						# Optional field.
+						continue
+					esac
+					# Unknown field.
+					_ob_parse_control_error \
+						"${file}" "${line_nr}" \
+						'control_unknown_field' \
+						"${name}"
 				fi
 				;;
 			' '*)  # Continuation line.
--
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