#!/bin/bash
#
#    $Revision: 1.13 $
#
# rpmdiff
#    Perform a diff on the files contained within different rpms and show
#    the result.
#    - Intended to be used on src rpms for comparing package builds but can
#      also be used on binary rpms.
#
# Copyright (C) 2005 Simon J. Mudd (sjmudd@pobox.com)
#
#    Newer versions of this script may be made available at:
#        http://ftp.wl0.org/rpmdiff
#
# Usage: rpmdiff [diffoptions] <from_rpm> <to_rpm>
#
# diffoptions:
#    Most of the single letter options allowable by GNU diff(1) are acceptable.
#    By default -uNr is used. If providing a value don't forget the -r option.
#
# Exit Status
#    Same as GNU diff(1): 0 = same, 1 = different and 2 = trouble.
#
# License:
#    This program 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 2
#    of the License, or (at your option) any later version.
#
#    This program 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 may have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
#    USA.
#
#    An on-line copy of the GNU General Public License can be found
#    http://www.fsf.org/copyleft/gpl.html.

[ -n "$DEBUG" ] && set -x
myname=$(basename $0)
myversion=$(echo '$Id: rpmdiff,v 1.13 2006/10/11 20:42:05 sjmudd Exp $' | awk '{ print $3 }')
rpm2cpio=rpm2cpio
cpio=cpio
cpiooptions="-idm --quiet"	# src rpms don't normally have directories but allow their creation

# fatal error and stop
msg_fatal () {
    echo "FATAL: $*" >&2
    exit 2
}

# standard message
msg_info () {
    echo "$*"
}

# cleanup on shutdown
cleanup () {
    test -n "${from_dir}" && test -d ${from_dir} && rm -rf ${from_dir}
    test -n "${to_dir}"   && test -d ${to_dir}   && rm -rf ${to_dir}
}

# extract rpm to given directory
# - the directory already exists
extract_rpm () {
    local local_rpm="$1"
    local local_dir="$2"

    msg_info "Extracting files from ${local_rpm} into $(basename ${local_dir})"
    ${rpm2cpio} ${local_rpm} |\
	( cd ${local_dir} && ${cpio} ${cpiooptions} ) ||\
    msg_fatal "problem extracting ${local_rpm} into ${local_dir}"
}

diffoptions=
while getopts bBcdeilnNuqrtTwy flag
do
	diffoptions="$diffoptions$flag"
done

shift $(($OPTIND - 1))

[ $# = 2 ] || msg_fatal "usage: rpmdiff [diffoptions] <from-rpm> <to-rpm>"

from_rpm="$1"
to_rpm="$2"
diffoptions=${diffoptions:-uNr}
tmpdir=${TMPDIR:-/tmp}

# checks if rpms are the same
[ "${from_rpm}" = "${to_rpm}" ] && msg_fatal "no difference between the same rpms"

# get the from
[ -n ${from_rpm} ] || msg_fatal "empty rpm ${from_rpm} (from)"
from_dir=$(mktemp -dp ${tmpdir} from.XXXXX) || msg_fatal "can not create directory for extracting ${from_rpm}"

# get the to
[ -n ${to_rpm} ] || msg_fatal "empty rpm ${to_rpm} (to)"
to_dir=$(mktemp -dp ${tmpdir} to.XXXXX) || msg_fatal "can not create directory for extracting ${to_rpm}"

# Clean up when done or when aborting.
trap cleanup 0 1 2 3 15

# extract if we have given an rpm name
extract_rpm ${from_rpm} ${from_dir}
extract_rpm ${to_rpm}   ${to_dir}

# get the metadata for non-src-RPMs (which have the spec file inside)
# - patch from Jan Iven <jan.iven@cern.ch>
if [[ ! ${from_rpm} =~ ".src.rpm\$" ]]; then
    rpm -qp --info --changelog --scripts --obsoletes --provides --requires --triggers ${from_rpm} > ${from_dir}/_RPM_METADATA
fi 
if [[ ! ${to_rpm} =~ ".src.rpm\$" ]]; then
    rpm -qp --info --changelog --scripts --obsoletes --provides --requires --triggers ${to_rpm} > ${to_dir}/_RPM_METADATA
fi 

msg_info "Performing diff -$diffoptions between $(basename ${from_rpm}) and $(basename ${to_rpm})"
msg_info ""
# perform a diff and change ${from_dir} -> ${from_rpm}, ${to_dir} -> ${to_rpm}
diff -${diffoptions} ${from_dir} ${to_dir} | \
	sed -e "s|${from_dir}|$(basename ${from_rpm})|" -e "s|${to_dir}|$(basename ${to_rpm})|"

# finished