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 19 package credentials
20 21 import (
22 "crypto/tls"
23 )
24 25 const alpnProtoStrH2 = "h2"
26 27 // AppendH2ToNextProtos appends h2 to next protos.
28 func 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.
46 func CloneTLSConfig(cfg *tls.Config) *tls.Config {
47 if cfg == nil {
48 return &tls.Config{}
49 }
50 51 return cfg.Clone()
52 }
53