#! /bin/sh

# Enhanced sccs diff utility for use with vc mode.
# This version is more compatible with rcsdiff(1).

# Copyright (C) 1992-1993, 1995, 1997, 2001-2012
#   Free Software Foundation, Inc.

# Author: Paul Eggert
# (according to authors.el)

# 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 <http://www.gnu.org/licenses/>.


DIFF="diff"
usage="$0: Usage: vcdiff [--brief] [-q] [-r<sid1>] [-r<sid2>] [diffopts] sccsfile..."

# Now that we use `sccs get' rather than just `get', we don't need this.
# PATH=$PATH:/usr/ccs/bin:/usr/sccs:/usr/xpg4/bin # common SCCS hangouts

echo="echo"
sid1= sid2=

for f
do
	case $f in
	-*)
		case $f in
		--brief)
			DIFF=cmp;;
		-q)
			echo=:;;
		-r?*)
			case $sid1 in
			'')
				sid1=$f
				;;
			*)
				case $sid2 in
				?*) echo "$usage" >&2; exit 2 ;;
				esac
				sid2=$f
				;;
			esac
			;;
		*)
			options="$options $f"
			;;
		esac
		shift
		;;
	*)
		break
		;;
	esac
done

case $# in
0)
	echo "$usage" >&2
	exit 2
esac


rev1= rev2= status=0
trap 'status=2; exit' 1 2 13 15
trap 'rm -f $rev1 $rev2 || status=2; exit $status' 0

for f
do
	s=2

	case $f in
	s.* | */s.*)
		if
			rev1=`mktemp /tmp/geta.XXXXXXXX`
			sccs get -s -p -k $sid1 "$f" > $rev1 &&
			case $sid2 in
			'')
				workfile=`expr " /$f" : '.*/s.\(.*\)'`
				;;
			*)
				rev2=`mktemp /tmp/getb.XXXXXXXX`
				sccs get -s -p -k $sid2 "$f" > $rev2
				workfile=$rev2
			esac
		then
			$echo $DIFF $options $rev1 $workfile >&2
			$DIFF $options $rev1 $workfile
			s=$?
		fi
		;;
	*)
		echo "$0: $f is not an SCCS file" >&2
	esac

	if test $status -lt $s
	then status=$s
	fi
done