shlibs_hash

#! /bin/sh
# brings hash API to SH
#
# Usage :
# HASH=$(hash_create)
# hash_set $HASH foo bar
# hash_get $HASH foo
# ...
# hash_destroy $HASH

hash_check() {
	[ -z "$1" ] && return 1
	[ ! -e "$1/0_shlib_hash.canary" ] && return 2
	return 0
}

hash_create() {
	HASH_DIR=$(mktemp -d)
	echo "hash for $0 : $$" > ${HASH_DIR}/0_shlib_hash.canary
	echo $HASH_DIR
}

hash_destroy() {
	hash_check "$@" && HASH_DIR="$1" || return 1
	shift

	rm -Rf "$HASH_DIR"
}

hash_len()
{
        hash_check "$@" && HASH_DIR="$1" || return 1
        shift

	(
		cd "$HASH_DIR"
		LAST_ELEM=$(ls -1r | head -n 1)
		[ "$LAST_ELEM" = "0_shlib_hash.canary" ] && echo 0 || echo $LAST_ELEM
	)
}

hash_set()
{
	hash_check "$@" && HASH_DIR="$1" || return 1
	shift

	(
		cd "$HASH_DIR"
		# XXX - Should be escaped !		
		HASH_ELEM="$1"
		shift
		echo "$@" > $HASH_ELEM
	)
}

hash_get()
{
        hash_check "$@" && HASH_DIR="$1" || return 1
        shift

	(
		cd "$HASH_DIR"
		# XXX - Should be escaped !		
		HASH_ELEM="$1"
		shift
		[ -r $HASH_ELEM ] && cat "$HASH_ELEM"
	)
}