forked from coreos/ignition
/
hash.go
81 lines (67 loc) · 1.8 KB
/
hash.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
// Copyright 2016 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package types
import (
"crypto"
"encoding/hex"
"encoding/json"
"errors"
"strings"
)
var (
ErrHashMalformed = errors.New("malformed hash specifier")
ErrHashWrongSize = errors.New("incorrect size for hash sum")
ErrHashUnrecognized = errors.New("unrecognized hash function")
)
type Hash struct {
Function string
Sum string
}
func (h *Hash) UnmarshalYAML(unmarshal func(interface{}) error) error {
return h.unmarshal(unmarshal)
}
func (h *Hash) UnmarshalJSON(data []byte) error {
return h.unmarshal(func(th interface{}) error {
return json.Unmarshal(data, th)
})
}
func (h Hash) MarshalJSON() ([]byte, error) {
return []byte(`"` + h.Function + "-" + h.Sum + `"`), nil
}
func (h *Hash) unmarshal(unmarshal func(interface{}) error) error {
var th string
if err := unmarshal(&th); err != nil {
return err
}
parts := strings.SplitN(th, "-", 2)
if len(parts) != 2 {
return ErrHashMalformed
}
h.Function = parts[0]
h.Sum = parts[1]
return h.assertValid()
}
func (h Hash) assertValid() error {
var hash crypto.Hash
switch h.Function {
case "sha512":
hash = crypto.SHA512
default:
return ErrHashUnrecognized
}
if len(h.Sum) != hex.EncodedLen(hash.Size()) {
return ErrHashWrongSize
}
return nil
}