live-build/scripts/build/chroot_cache

#!/bin/sh

## live-build(7) - System Build Scripts
## Copyright (C) 2016-2020 The Debian Live team
## Copyright (C) 2006-2015 Daniel Baumann <mail@daniel-baumann.ch>
##
## This program comes with ABSOLUTELY NO WARRANTY; for details see COPYING.
## This is free software, and you are welcome to redistribute it
## under certain conditions; see COPYING for details.


set -e

# Including common functions
[ -e "${LIVE_BUILD}/scripts/build.sh" ] && . "${LIVE_BUILD}/scripts/build.sh" || . /usr/lib/live/build.sh

# Setting static variables
DESCRIPTION="Cache chroot stage"
USAGE="${PROGRAM} {restore|save} [--force]"

# Processing arguments and configuration files
Init_config_data "${@}"

_ACTION="${1}"
shift

if ! In_list "chroot" ${LB_CACHE_STAGES}
then
	exit 0
fi

# Set non-default stage file name
# Setting to default name with appended action name
STAGE_FILE="$(Stagefile_name "${_ACTION}")"

case "${_ACTION}" in
	restore)
		Echo_message "Restoring chroot stage from cache..."

		# Checking stage file
		Check_stagefile "${STAGE_FILE}"

		if [ -d cache/chroot ]
		then
			# Acquire lock file
			Acquire_lockfile

			# Removing old chroot
			rm -rf chroot

			# Restoring old cache
			cp -a cache/chroot chroot

			# Creating stage file
			Create_stagefile "${STAGE_FILE}"

			exit 0
		fi
		;;

	save)
		Echo_message "Saving chroot stage to cache..."

		# Checking stage file
		Check_stagefile "${STAGE_FILE}"

		# Acquire lock file
		Acquire_lockfile

		rm -rf cache/chroot

		mkdir -p cache

		cp -a chroot cache/chroot

		# Creating stage file
		Create_stagefile "${STAGE_FILE}"
		;;

	*)
		Echo_error "Invalid action parameter: '${_ACTION}'"
		Usage --fail
		;;
esac