// Err returns the most recent decoder error if any, or nil
func (d *Decoder) Err() error { return d.err }

// MaxDepth will set the maximum recursion depth.
// If the maximum depth is exceeded, ErrMaxDepth is returned.
// Less than or 0 means no limit (default).
func (d *Decoder) MaxDepth(n int) *Decoder {
	d.maxDepth = n
	return d
}

// Decode parses the JSON-encoded data and returns an interface value

// keys, so we need to use this technique to merge the
// keys.
func sanitizePolicy(r io.Reader) (io.Reader, error) {
	var buf bytes.Buffer
	e := json.NewEncoder(&buf)
	d := jstream.NewDecoder(r, 0).ObjectAsKVS().MaxDepth(10)
	sset := set.NewStringSet()
	for mv := range d.Stream() {
		var kvs jstream.KVS
		if mv.ValueType == jstream.Object {
			// This is a JSON object type (that preserves key order)
			kvs = mv.Value.(jstream.KVS)