-
Notifications
You must be signed in to change notification settings - Fork 1
/
default.go
114 lines (106 loc) · 3.11 KB
/
default.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
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package defval marshals and unmarshals textual forms of default values.
//
// This package handles both the form historically used in Go struct field tags
// and also the form used by google.protobuf.FieldDescriptorProto.default_value
// since they differ in superficial ways.
package defval
import (
"fmt"
"math"
"strconv"
"google.golang.org/protobuf/reflect/protoreflect"
)
// Format is the serialization format used to represent the default value.
type Format int
const (
_ Format = iota
// GoTag uses the historical serialization format in Go struct field tags.
GoTag
)
// Marshal serializes v as the default string according to the given kind k.
// When specifying the Descriptor format for an enum kind, the associated
// enum value descriptor must be provided.
func Marshal(v protoreflect.Value, ev protoreflect.EnumValueDescriptor, k protoreflect.Kind, f Format) (string, error) {
switch k {
case protoreflect.BoolKind:
if f == GoTag {
if v.Bool() {
return "1", nil
} else {
return "0", nil
}
} else {
if v.Bool() {
return "true", nil
} else {
return "false", nil
}
}
case protoreflect.EnumKind:
if f == GoTag {
return strconv.FormatInt(int64(v.Enum()), 10), nil
} else {
return string(ev.Name()), nil
}
case protoreflect.Int32Kind, protoreflect.Sint32Kind, protoreflect.Sfixed32Kind, protoreflect.Int64Kind, protoreflect.Sint64Kind, protoreflect.Sfixed64Kind:
return strconv.FormatInt(v.Int(), 10), nil
case protoreflect.Uint32Kind, protoreflect.Fixed32Kind, protoreflect.Uint64Kind, protoreflect.Fixed64Kind:
return strconv.FormatUint(v.Uint(), 10), nil
case protoreflect.FloatKind, protoreflect.DoubleKind:
f := v.Float()
switch {
case math.IsInf(f, -1):
return "-inf", nil
case math.IsInf(f, +1):
return "inf", nil
case math.IsNaN(f):
return "nan", nil
default:
if k == protoreflect.FloatKind {
return strconv.FormatFloat(f, 'g', -1, 32), nil
} else {
return strconv.FormatFloat(f, 'g', -1, 64), nil
}
}
case protoreflect.StringKind:
// String values are serialized as is without any escaping.
return v.String(), nil
case protoreflect.BytesKind:
if s, ok := marshalBytes(v.Bytes()); ok {
return s, nil
}
}
return "", fmt.Errorf("could not format value for %v: %v", k, v)
}
// marshalBytes serializes bytes by using C escaping.
// To match the exact output of protoc, this is identical to the
// CEscape function in strutil.cc of the protoc source code.
func marshalBytes(b []byte) (string, bool) {
var s []byte
for _, c := range b {
switch c {
case '\n':
s = append(s, `\n`...)
case '\r':
s = append(s, `\r`...)
case '\t':
s = append(s, `\t`...)
case '"':
s = append(s, `\"`...)
case '\'':
s = append(s, `\'`...)
case '\\':
s = append(s, `\\`...)
default:
if printableASCII := c >= 0x20 && c <= 0x7e; printableASCII {
s = append(s, c)
} else {
s = append(s, fmt.Sprintf(`\%03o`, c)...)
}
}
}
return string(s), true
}