#! /bin/bash

# creating a broken out RT patch set


#-----  process script arguments

diff_patches=0
diff_series=0
save_diff=0
verbose=0

old_argc=0
while [[ ($# != ${old_argc}) && ($# > 0) ]] ; do
	old_argc=$#
	case $1 in
		-h | -help | --help )
			shift $# ;;
		--patches )
			diff_patches=1
			shift 1;;
		--sd )
			save_diff=1
			diff_file=$2
			shift 2;;
		--series )
			diff_series=1
			shift 1;;
		-v | --verbose )
			verbose=1
			shift ;;
	esac
done

if (( ($# < 1) || ($# > 2) )) ; then
	echo ""                                                                   >&2
	echo "usage: `basename $0` OLD_RT_KERNEL_VERSION NEW_RT_KERNEL_VERSION"   >&2
	echo "            -h         print this usage text"                       >&2
	echo "            -help      synonym for -h"                              >&2
	echo "           --help      synonym for -h"                              >&2
	echo "           --sd FILE   save diff file as FILE"                      >&2
	echo "            -v         verbose output"                              >&2
	echo "            -verbose   synonym for -v"                              >&2
	echo "           --verbose   synonym for -v"                              >&2
	echo ""                                                                   >&2
	echo "   examples:"                                                       >&2
	echo "       compare 3.0.12-rt29 to 3.0.32-rt52"                          >&2
	echo "          `basename $0` 3.0.12-rt29 3.0.32-rt52"                    >&2
	echo ""                                                                   >&2
	echo "   notes:"                                                          >&2
	echo ""                                                                   >&2
	echo "     --patches does not show changes to the series file,"           >&2
	echo "               contents of deleted patches, and contents"           >&2
	echo "               of added patches"                                    >&2
	echo ""                                                                   >&2
	exit 1
fi



# Choose the versions to be compared

#old_rt_version=3.0.12-rt29
#new_rt_version=3.0.23-rt38


old_rt_version=$1
old_patch_dir=patches_${old_rt_version}

new_rt_version=$2
new_patch_dir=patches_${new_rt_version}


#-----  error checks

if [[ ! -d ${old_patch_dir} ]] ; then
	echo ""                                                                   >&2
	echo "ERROR:"                                                             >&2
	echo "  Root patch directory ${old_patch_dir} does not exist"             >&2
	echo ""                                                                   >&2
	exit 1
fi


if [[ ! -d ${new_patch_dir} ]] ; then
	echo ""                                                                   >&2
	echo "ERROR:"                                                             >&2
	echo "  Root patch directory ${new_patch_dir} does not exist"             >&2
	echo ""                                                                   >&2
	exit 1
fi

if [[ "${diff_patches}" == "0" && "${diff_series}" == "0" ]] ; then
	echo ""                                                                   >&2
	echo "ERROR:"                                                             >&2
	echo "  no type of diff specified"                                        >&2
	echo ""                                                                   >&2
	exit 1
fi


#-----  patches added or deleted

# two different ways to see the same info, comment out the second way

if [[ "${diff_series}" == "1" ]] ; then

	echo

	diff -u {${old_patch_dir},${new_patch_dir}}/series \
		| grep -v "^--- " \
		| grep -v "^\+\+\+ " \
		| grep "^[-]" \
		| sort

	echo

	diff -u {${old_patch_dir},${new_patch_dir}}/series \
		| grep -v "^--- " \
		| grep -v "^\+\+\+ " \
		| grep "^[+]" \
		| sort

#	echo
#	echo
#
#	cat ${diff_file} | grep "^Only in ${old_patch_dir}" | sort
#
#	echo
#
#	cat ${diff_file} | grep "^Only in ${new_patch_dir}" | sort

	echo

fi


#-----  Changes to patch files

if [[ "${diff_patches}" == "1" ]] ; then

	if [[ "${save_diff}" == "1" ]] ; then

		if [[ "${diff_file}" == "" ]] ; then
			echo ""                                                             >&2
			echo "ERROR:"                                                       >&2
			echo "  -sd FILE name is blank"                                     >&2
			echo ""                                                             >&2
			exit 1
		fi

		if [[ -a ${diff_file} ]] ; then
			echo ""                                                             >&2
			echo "ERROR:"                                                       >&2
			echo "  ${diff_file} already exists"                                >&2
			echo ""                                                             >&2
			exit 1
		fi

	else
		diff_file=`mktemp`
	fi

	diff -x series -ru ${old_patch_dir}/ ${new_patch_dir}/ > ${diff_file}


	# (the files which are listed, but contain no # + or - lines are due to
	# changed commit IDs and Subject lines from rebasing)
	#
	# Changes that are "^[+-][+-]" are changes to the patch.
	#
	# Changes that are "^[+-] "    are changes of context.

	cat ${diff_file} \
		| grep -v "^[+-]From " \
		| grep -v "^[+-]Subject: "  \
		| grep -v "^--- ${old_patch_dir}" \
		| grep -v "^+++ ${new_patch_dir}" \
		| grep -E "(^diff |^[+-])" \
		| grep -v  "^[+-]index " \
		| grep -v  "^[+-]@@ "


	#-----  clean up

	if [[ "${save_diff}" == "0" ]] ; then
		rm ${diff_file}
	fi

fi

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