Function cloneHash

handshake_server_tls13.go:568–591

cloneHash uses the encoding.BinaryMarshaler and encoding.BinaryUnmarshaler interfaces implemented by standard library hashes to clone the state of in to a new instance of h. It returns nil if the operation fails.

(in hash.Hash, h crypto.Hash)

// interfaces implemented by standard library hashes to clone the state of in
// to a new instance of h. It returns nil if the operation fails.
func cloneHash(in hash.Hash, h crypto.Hash) hash.Hash {
	// Recreate the interface to avoid importing encoding.
	type binaryMarshaler interface {
		MarshalBinary() (data []byte, err error)
		UnmarshalBinary(data []byte) error
	}
	marshaler, ok := in.(binaryMarshaler)
	if !ok {
		return nil
	}
	state, err := marshaler.MarshalBinary()
	if err != nil {
		return nil
	}
	out := h.New()
	unmarshaler, ok := out.(binaryMarshaler)
	if !ok {
		return nil
	}
	if err := unmarshaler.UnmarshalBinary(state); err != nil {
		return nil
	}
	return out
}

func (hs *serverHandshakeStateTLS13) pickCertificate() error {
	c := hs.c