#!/bin/sh
# gentoo-infra: infra/githooks.git:update-01-basic

# --- Command line
refname=${1}
oldrev=${2}
newrev=${3}

# --- Safety check
if [ -z "${GIT_DIR}" ]; then
	echo "Don't run this script from the command line." >&2
	echo " (if you want, you could supply GIT_DIR then run" >&2
	echo "  ${0} <ref> <oldrev> <newrev>)" >&2
	exit 1
fi

if [ -z "${refname}" -o -z "${oldrev}" -o -z "${newrev}" ]; then
	echo "usage: ${0} <ref> <oldrev> <newrev>" >&2
	exit 1
fi

# --- Check types
# if $newrev is 0000...0000, it's a commit to delete a ref.
zero="0000000000000000000000000000000000000000"

case ${refname} in
	refs/tags/*)
		echo "*** Tags are not allowed in the gentoo repo" >&2
		exit 1
		;;
	refs/heads/master)
		if [ "${newrev}" = "${zero}" ]; then
			echo "*** Errr, removing master is not allowed" >&2
			exit 1
		fi

		# prevent forced updates
		# http://stackoverflow.com/questions/10319110/how-to-detect-a-forced-update
		if [ -n "$(git rev-list "${oldrev}" "^${newrev}")" ]; then
			echo "*** Forced update disallowed!" >&2
			exit 1
		fi

		IFS='
'

		# check that tree is sane
		# (we don't have to filter out removals -- the files weren't
		# allowed, so we won't remove them :))
		cfiles=$(git diff --name-only "${oldrev}".."${newrev}")
		for name in ${cfiles}; do
			case ${name} in
				*/ChangeLog)
					echo "*** ChangeLogs are not allowed in the repository"
					exit 1
					;;
				metadata/*cache*)
					echo "*** Metadata Cache is not allowed in the repository"
					exit 1
					;;
				metadata/glsa*)
					echo "*** GLSAs are not allowed in the repository"
					exit 1
					;;
				metadata/news*)
					echo "*** News is not allowed in the repository"
					exit 1
					;;
				metadata/herds.xml|metadata/dtd*|metadata/timestamp*)
					echo "*** Metadata is not allowed in the repository"
					exit 1
					;;
				profiles/use.local.desc)
					echo "*** Use.local.desc is not allowed in the repository"
					exit 1
					;;
			esac
		done

		;;
	refs/heads/*)
		# dev branches are fine whatever they are
		;;
	refs/notes/*)
		# allow git notes, why not?
		;;
	*)
		echo "*** Unknown object refused" >&2
		exit 1
		;;
esac

# --- Finished
exit 0