makepkg: break out checksum generation to its own function

This also fixes a "bug" in which a PKGBUILD without any source array
would generate "md5sums=()". While not technically wrong, we can easily
do better and emit nothing at all.

scripts/makepkg.sh.in

@@ -1119,32 +1119,16 @@ get_integlist() {
 	fi
 }
 
-generate_checksums() {
+generate_one_checksum() {
-	msg "$(gettext "Generating checksums for source files...")"
+	local integ=$1 numsrc=${#source[*]} indentsz idx
 
-	if ! type -p openssl >/dev/null; then
+	if (( numsrc == 0 )); then
-		error "$(gettext "Cannot find the %s binary required for generating sourcefile checksums.")" "openssl"
+		return
-		exit 1 # $E_MISSING_PROGRAM
 	fi
 
-	local integlist
+	printf "%ssums=(%n" "$integ" indentsz
-	if (( $# == 0 )); then
-		IFS=$'\n' read -rd '' -a integlist < <(get_integlist)
-	else
-		integlist=("$@")
-	fi
 
-	local integ
+	for (( idx = 0; idx < numsrc; ++idx )); do
-	for integ in "${integlist[@]}"; do
-		if ! in_array "$integ" "${known_hash_algos[@]}"; then
-			error "$(gettext "Invalid integrity algorithm '%s' specified.")" "$integ"
-			exit 1 # $E_CONFIG_ERROR
-		fi
-
-		local indentsz idx numsrc=${#source[@]}
-		printf "%s%n" "${integ}sums=(" indentsz
-
-		for (( idx = 0; idx < numsrc; i++ )); do
 		local netfile=${source[idx]}
 		local proto sum
 		proto="$(get_protocol "$netfile")"
@@ -1169,10 +1153,35 @@ generate_checksums() {
 		printf "%*s%s" $(( idx ? indentsz : 0 )) '' "'$sum'"
 
 		# print a newline on lines before the last
-			(( ++idx < numsrc )) && echo
+		(( idx < (numsrc - 1) )) && echo
 	done
 
 	echo ")"
+}
+
+generate_checksums() {
+	msg "$(gettext "Generating checksums for source files...")"
+
+	if ! type -p openssl >/dev/null; then
+		error "$(gettext "Cannot find the %s binary required for generating sourcefile checksums.")" "openssl"
+		exit 1 # $E_MISSING_PROGRAM
+	fi
+
+	local integlist
+	if (( $# == 0 )); then
+		IFS=$'\n' read -rd '' -a integlist < <(get_integlist)
+	else
+		integlist=("$@")
+	fi
+
+	local integ
+	for integ in "${integlist[@]}"; do
+		if ! in_array "$integ" "${known_hash_algos[@]}"; then
+			error "$(gettext "Invalid integrity algorithm '%s' specified.")" "$integ"
+			exit 1 # $E_CONFIG_ERROR
+		fi
+
+		generate_one_checksum "$integ"
 	done
 }