#!/bin/bash

# Author: Thomas Renninger <trenn@suse.de>
# This code is covered and distributed under
# the General Public Licence v2

function usage(){
    echo "$(basename $0) [ git_tag ]"
    echo
    echo "git_tag   must be a valid kernel git tag, for example v3.1"
    echo "          if git_tag is not passed HEAD will be used which"
    echo "          may produce a package incompatible tarball name"
    echo "          BEST ALWAYS PASS AN EXISTING TAG"
    echo "          cpupower got introduced in 3.1-rc1"
    echo
    echo "export GIT_DIR= environment variable if the git repo is not the current directory"
    echo "For example: GIT_DIR=/path_to_git_repo/.git"
}

if [ $# -eq 1 ];then
    if [ "$1" = "-h" ] || [ "$1" == "--help" ];then
	usage
	exit 0
    fi
    GIT_TAG="$1"
    echo "Exporting cpupower from kernel version $GIT_TAG"
    # convert - to . as package versions do not allow -
    VERSION="${GIT_TAG/-/.}"
    # remove leading v
    VERSION="-${VERSION#v}"
else
    GIT_TAG="HEAD"
    VERSION=""
fi

# Tried to do this with one git archive command, but
# --remote= param seem not to be configured for kernel.org gits

# set -x
DIR=`mktemp -d`
pushd "$DIR"
git archive --format=tar $GIT_TAG tools/power/cpupower |tar -x
mv tools/power/cpupower cpupower${VERSION}
tar -cvjf cpupower${VERSION}.tar.bz2 cpupower${VERSION}
popd
mv "$DIR/cpupower${VERSION}".tar.bz2 .
rm -rf "$DIR"
# set +x
echo cpupower${VERSION}.tar.bz2