#!/bin/sh

echo_and_exec()
{
    # echo the argument vector and execute it:
    {
	printf '$'
	printf ' %s' ${1+"$@"}
	printf '\n'
    } >&2
    ${1+"$@"}
}

count=0

create_HIERARCHY()
{
    printf >&2 '# Creating hierarchy    %s\n' "${1?}"
    mkdir -p -- "${1?}" && \
    dd if=/dev/zero count="$count" bs=1 of="$1"/file 2> /dev/null
    count="`expr "$count" + 1`"
}

hardlink_HIERARCHY_to_BACKUPHIERARCHY ()
{
    hierarchy="${1?}" && backuphierarchy="${2?}" && shift 2 && \
    printf >&2 '# Hardlinking hierarchy %s\n' "$hierarchy" && \
    (cd "$hierarchy" && exec find . -print) | \
    while read file
    do
	if test -d "$hierarchy"/"$file"
	then
	    mkdir -p -- "$backuphierarchy"/"$file"
	else
	    ln -f -- "$hierarchy"/"$file" "$backuphierarchy"/"$file"
	fi || return
    done
}

create_ARCHIVE_from_HIERARCHY()
{
    echo_and_exec tar -c -f "${1?}" -- -C "${2?}" file
}

extract_ARCHIVE_to_HIERARCHY_with_OPTIONS()
{
    archive="${1?}" && hierarchy="${2?}" && shift 2 && \
    {
	{
	    printf '$ tar -x -f %s' "$archive"
	    if test -n "${1+defined}"
	    then
		printf ' %s' ${1+"$@"}
	    fi
	    printf ' \\\n'
	    printf '      -- -C %s\n' "$hierarchy"
	} >&2
	tar -x -f "$archive" ${1+"$@"} -- -C "$hierarchy"
    }
}

lookup_ARCHIVE_in_HIERARCHIES()
{
    archive="${1?}" && shift && \
    for hierarchy in ${1+"$@"}
    do
	tar -t -f "$archive" | \
	while read member
	do
	    echo "$hierarchy"/"$member"
	done
    done | \
    {
	# put all filenames into argv:

	# clear argv and set initial empty arg1:
	set ''
	while read file
	do
	    set ${1+"$@"} "$file"
	done
	# remove initial '' arg1
	shift
	if test "$#" -ge 1
	then
	    {
		printf '$ ls -dogi -ctr --'
		if test "$#" -eq 1
		then
		    format=' %s'
		else
		    format=' \\\n     %s'
		fi
		printf "$format" ${1+"$@"}
		printf '\n'
	    } >&2
	    ls -dogi -ctr -- ${1+"$@"}
	fi
    }
}

echo_and_exec uname -srm
echo_and_exec tar --version

echo_and_exec rm -rf -- archive 1 2 && \
{
    ec=0
    for testcase in older/keep-newer-files \
	older/keep-newer-files_overwrite older/overwrite_keep-newer-files \
	older/keep-newer-files_unlink-first older/unlink-first_keep-newer-files
    do
	create_HIERARCHY 1/"$testcase" && \
	hardlink_HIERARCHY_to_BACKUPHIERARCHY 1/"$testcase" 2/"$testcase"
	ec="$?"
	if test "$ec" -ne 0
	then
	    break
	fi
    done
    (exit "$ec")
} && \
echo_and_exec sleep 3 && \
create_HIERARCHY archive && \
create_ARCHIVE_from_HIERARCHY archive.tar archive && \
{
    echo '# table of contents of archive archive.tar:'
    echo_and_exec tar -tv -f archive.tar
} && \
echo_and_exec sleep 3 && \
{
    ec=0
    for testcase in newer/keep-newer-files \
	newer/keep-newer-files_overwrite newer/overwrite_keep-newer-files \
	newer/keep-newer-files_unlink-first newer/unlink-first_keep-newer-files
    do
	create_HIERARCHY 1/"$testcase" && \
	hardlink_HIERARCHY_to_BACKUPHIERARCHY 1/"$testcase" 2/"$testcase"
	ec="$?"
	if test "$ec" -ne 0
	then
	    break
	fi
    done
    (exit "$ec")
} && \
echo_and_exec sleep 3 && \
{
    lookup_ARCHIVE_in_HIERARCHIES archive.tar \
	1/older/keep-newer-files \
	2/older/keep-newer-files \
	1/older/keep-newer-files_overwrite \
	2/older/keep-newer-files_overwrite \
	1/older/overwrite_keep-newer-files \
	2/older/overwrite_keep-newer-files \
	1/older/keep-newer-files_unlink-first \
	2/older/keep-newer-files_unlink-first \
	1/older/unlink-first_keep-newer-files \
	2/older/unlink-first_keep-newer-files \
	archive \
	1/newer/keep-newer-files \
	2/newer/keep-newer-files \
	1/newer/keep-newer-files_overwrite \
	2/newer/keep-newer-files_overwrite \
	1/newer/overwrite_keep-newer-files \
	2/newer/overwrite_keep-newer-files \
	1/newer/keep-newer-files_unlink-first \
	2/newer/keep-newer-files_unlink-first \
	1/newer/unlink-first_keep-newer-files \
	2/newer/unlink-first_keep-newer-files

    extract_ARCHIVE_to_HIERARCHY_with_OPTIONS \
	archive.tar 1/older/keep-newer-files --keep-newer-files
    lookup_ARCHIVE_in_HIERARCHIES \
	archive.tar 1/older/keep-newer-files
    extract_ARCHIVE_to_HIERARCHY_with_OPTIONS \
	archive.tar 1/older/keep-newer-files_overwrite \
	--keep-newer-files --overwrite
    lookup_ARCHIVE_in_HIERARCHIES \
	archive.tar 1/older/keep-newer-files_overwrite
    extract_ARCHIVE_to_HIERARCHY_with_OPTIONS \
	archive.tar 1/older/overwrite_keep-newer-files \
	--overwrite --keep-newer-files
    lookup_ARCHIVE_in_HIERARCHIES \
	archive.tar 1/older/overwrite_keep-newer-files

    extract_ARCHIVE_to_HIERARCHY_with_OPTIONS \
	archive.tar 1/older/keep-newer-files_unlink-first \
	--keep-newer-files --unlink-first
    lookup_ARCHIVE_in_HIERARCHIES \
	archive.tar 1/older/keep-newer-files_unlink-first
    extract_ARCHIVE_to_HIERARCHY_with_OPTIONS \
	archive.tar 1/older/unlink-first_keep-newer-files \
	--unlink-first --keep-newer-files
    lookup_ARCHIVE_in_HIERARCHIES \
	archive.tar 1/older/unlink-first_keep-newer-files

    extract_ARCHIVE_to_HIERARCHY_with_OPTIONS \
	archive.tar 1/newer/keep-newer-files \
	--keep-newer-files
    lookup_ARCHIVE_in_HIERARCHIES \
	archive.tar 1/newer/keep-newer-files
    extract_ARCHIVE_to_HIERARCHY_with_OPTIONS \
	archive.tar 1/newer/keep-newer-files_overwrite \
	--keep-newer-files --overwrite
    lookup_ARCHIVE_in_HIERARCHIES \
	archive.tar 1/newer/keep-newer-files_overwrite
    extract_ARCHIVE_to_HIERARCHY_with_OPTIONS \
	archive.tar 1/newer/overwrite_keep-newer-files \
	--overwrite --keep-newer-files
    lookup_ARCHIVE_in_HIERARCHIES \
	archive.tar 1/newer/overwrite_keep-newer-files

    extract_ARCHIVE_to_HIERARCHY_with_OPTIONS \
	archive.tar 1/newer/keep-newer-files_unlink-first \
	--keep-newer-files --unlink-first
    lookup_ARCHIVE_in_HIERARCHIES \
	archive.tar 1/newer/keep-newer-files_unlink-first
    extract_ARCHIVE_to_HIERARCHY_with_OPTIONS \
	archive.tar 1/newer/unlink-first_keep-newer-files \
	--unlink-first --keep-newer-files
    lookup_ARCHIVE_in_HIERARCHIES \
	archive.tar 1/newer/unlink-first_keep-newer-files
}