Auxiliary function for args checks.

src/scripts/common.sh

 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Common constants for build scripts
 # This must evaluate properly for both /bin/bash and /bin/sh
 
 # All scripts should die on error unless commands are specifically excepted
 # by prefixing with '!' or surrounded by 'set +e' / 'set -e'.
 # TODO: Re-enable this once shflags is less prone to dying.
@@ skipping 237 matching lines @@
   local file=$1
   local whitelist="$FLAGS_whitelist"
   test -f "$whitelist" || (echo "Whitelist file missing ($whitelist)" && exit 1)
 
   local checksum=$(md5sum "$file" | awk '{ print $1 }')
   local count=$(sed -e "s/#.*$//" "${whitelist}" | grep -c "$checksum" \
                 || /bin/true)
   test $count -ne 0
 }
 
+# Check that all arguments are flags; that is, there are no remaining arguments
+# after parsing from shflags.  Allow (with a warning) a single empty-string
+# argument.
+#
+# TODO: fix buildbot so that it doesn't pass the empty-string parameter,
+# then change this function.
+#
+# Usage: check_flags_only_and_allow_null_arg "$@" && set --
+function check_flags_only_and_allow_null_arg {
+  do_shift=1
+  if [[ $# == 1 && -z "$@" ]]; then
+    echo "$0: warning: ignoring null argument" >&2
+    shift
+    do_shift=0
+  fi
+  if [[ $# -gt 0 ]]; then
+    echo "error: invalid arguments: \"$@\"" >&2
+    flags_help
+    exit 1
+  fi
+  return $do_shift
+}
+
 V_RED="\e[31m"
 V_YELLOW="\e[33m"
 
 function warn {
   echo -e "${V_YELLOW}Warning..: $1${V_VIDOFF}"
 }
 
 function error {
   echo -e "${V_RED}Error....: $1${V_VIDOFF}"
 }