-
Notifications
You must be signed in to change notification settings - Fork 10
/
string.go
136 lines (120 loc) · 3.46 KB
/
string.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
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
// Package null contains SQL types that consider zero input and null input as separate values,
// with convenient support for JSON and text marshaling.
// Types in this package will always encode to their null value if null.
// Use the zero subpackage if you want zero values and null to be treated the same.
package null
import (
"database/sql"
"encoding/json"
"fmt"
"math/rand"
"reflect"
"github.com/google/uuid"
)
// String is a nullable string. It supports SQL and JSON serialization.
// It will marshal to null if null. Blank string input will be considered null.
type String struct {
sql.NullString
}
// StringFrom creates a new String that will never be blank.
func StringFrom(s string) String {
return NewString(s, true)
}
// StringFromRandom creates a new random String that will never be blank.
func StringFromRandom(n int) String {
var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
b := make([]rune, n)
for i := range b {
b[i] = letters[rand.Intn(len(letters))]
}
return NewString(string(b), true)
}
// StringFromUUID creates a new String that will never be blank.
func StringFromUUID() String {
return NewString(uuid.Must(uuid.NewUUID()).String(), true)
}
// StringFromPtr creates a new String that be null if s is nil.
func StringFromPtr(s *string) String {
if s == nil {
return NewString("", false)
}
return NewString(*s, true)
}
// ValueOrZero returns the inner value if valid, otherwise zero.
func (s String) ValueOrZero() string {
if !s.Valid {
return ""
}
return s.String
}
// NewString creates a new String
func NewString(s string, valid bool) String {
return String{
NullString: sql.NullString{
String: s,
Valid: valid,
},
}
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports string and null input. Blank string input does not produce a null String.
// It also supports unmarshalling a sql.NullString.
func (s *String) UnmarshalJSON(data []byte) error {
var err error
var v interface{}
if err = json.Unmarshal(data, &v); err != nil {
return err
}
switch x := v.(type) {
case string:
s.String = x
case map[string]interface{}:
err = json.Unmarshal(data, &s.NullString)
case nil:
s.Valid = false
return nil
default:
err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.String", reflect.TypeOf(v).Name())
}
s.Valid = err == nil
return err
}
// MarshalJSON implements json.Marshaler.
// It will encode null if this String is null.
func (s String) MarshalJSON() ([]byte, error) {
if !s.Valid {
return []byte("null"), nil
}
return json.Marshal(s.String)
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a blank string when this String is null.
func (s String) MarshalText() ([]byte, error) {
if !s.Valid {
return []byte{}, nil
}
return []byte(s.String), nil
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null String if the input is a blank string.
func (s *String) UnmarshalText(text []byte) error {
s.String = string(text)
s.Valid = s.String != ""
return nil
}
// SetValid changes this String's value and also sets it to be non-null.
func (s *String) SetValid(v string) {
s.String = v
s.Valid = true
}
// Ptr returns a pointer to this String's value, or a nil pointer if this String is null.
func (s String) Ptr() *string {
if !s.Valid {
return nil
}
return &s.String
}
// IsZero returns true for null strings, for potential future omitempty support.
func (s String) IsZero() bool {
return !s.Valid
}