1/*
 2 *
 3 * Copyright 2020 gRPC authors.
 4 *
 5 * Licensed under the Apache License, Version 2.0 (the "License");
 6 * you may not use this file except in compliance with the License.
 7 * You may obtain a copy of the License at
 8 *
 9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19package credentials
20
21import (
22	"crypto/tls"
23)
24
25const alpnProtoStrH2 = "h2"
26
27// AppendH2ToNextProtos appends h2 to next protos.
28func AppendH2ToNextProtos(ps []string) []string {
29	for _, p := range ps {
30		if p == alpnProtoStrH2 {
31			return ps
32		}
33	}
34	ret := make([]string, 0, len(ps)+1)
35	ret = append(ret, ps...)
36	return append(ret, alpnProtoStrH2)
37}
38
39// CloneTLSConfig returns a shallow clone of the exported
40// fields of cfg, ignoring the unexported sync.Once, which
41// contains a mutex and must not be copied.
42//
43// If cfg is nil, a new zero tls.Config is returned.
44//
45// TODO: inline this function if possible.
46func CloneTLSConfig(cfg *tls.Config) *tls.Config {
47	if cfg == nil {
48		return &tls.Config{}
49	}
50
51	return cfg.Clone()
52}