#!/bin/sh
# Check the format of GNU Emacs change log entries.

# Copyright 2019 Free Software Foundation, Inc.

# This file is part of GNU Emacs.

# GNU Emacs is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# GNU Emacs is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

COMMIT_MSG_FILE=$1
COMMIT_SOURCE=$2
SHA1=$3

# Prefer gawk if available, as it handles NUL bytes properly.
if type gawk >/dev/null 2>&1; then
  awk=gawk
else
  awk=awk
fi

# Use a UTF-8 locale if available, so that the UTF-8 check works.
# Use U+00A2 CENT SIGN to test whether the locale works.
cent_sign_utf8_format='\302\242\n'
cent_sign=`printf "$cent_sign_utf8_format"`
print_at_sign='BEGIN {print substr("'$cent_sign'@", 2)}'
at_sign=`$awk "$print_at_sign" </dev/null 2>/dev/null`
if test "$at_sign" != @; then
  at_sign=`LC_ALL=en_US.UTF-8 $awk "$print_at_sign" </dev/null 2>/dev/null`
  if test "$at_sign" = @; then
    LC_ALL=en_US.UTF-8
  else
    LC_ALL=C
  fi
  export LC_ALL
fi

exec $awk -v at_sign="$at_sign" -v cent_sign="$cent_sign" -v file="$COMMIT_MSG_FILE" '
  /^Signed-off-by: / {
    print "'\''Signed-off-by:'\'' in commit message"
    status = 1
  }
  END {
    if (status != 0) {
      print "Commit aborted; please see the file 'CONTRIBUTE'"
    }
    exit status
  }
' <"$COMMIT_MSG_FILE"