forked from alecthomas/kingpin
-
Notifications
You must be signed in to change notification settings - Fork 0
/
flags.go
214 lines (188 loc) · 4.75 KB
/
flags.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
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
package kingpin
import (
"fmt"
"strings"
)
type flagGroup struct {
short map[string]*FlagClause
long map[string]*FlagClause
flagOrder []*FlagClause
}
func newFlagGroup() *flagGroup {
return &flagGroup{
short: make(map[string]*FlagClause),
long: make(map[string]*FlagClause),
}
}
// Flag defines a new flag with the given long name and help.
func (f *flagGroup) Flag(name, help string) *FlagClause {
flag := newFlag(name, help)
f.long[name] = flag
f.flagOrder = append(f.flagOrder, flag)
return flag
}
func (f *flagGroup) init() {
for _, flag := range f.long {
flag.init()
if flag.shorthand != 0 {
f.short[string(flag.shorthand)] = flag
}
}
}
func (f *flagGroup) parse(tokens tokens, ignoreRequired bool) (tokens, error) {
// Track how many required flags we've seen.
remaining := make(map[string]struct{})
for k, flag := range f.long {
if flag.required && !ignoreRequired {
remaining[k] = struct{}{}
}
}
var token *token
loop:
for {
token, tokens = tokens.Next()
switch token.Type {
case TokenEOF:
break loop
case TokenLong, TokenShort:
flagToken := token
defaultValue := ""
var flag *FlagClause
var ok bool
invert := false
name := token.Value
if token.Type == TokenLong {
if strings.HasPrefix(name, "no-") {
name = name[3:]
invert = true
}
flag, ok = f.long[name]
if !ok {
return nil, fmt.Errorf("unknown long flag '%s'", flagToken)
}
} else {
flag, ok = f.short[name]
if !ok {
return nil, fmt.Errorf("unknown short flag '%s", flagToken)
}
}
delete(remaining, flag.name)
fb, ok := flag.value.(boolFlag)
if ok && fb.IsBoolFlag() {
if invert {
defaultValue = "false"
} else {
defaultValue = "true"
}
} else {
if invert {
return nil, fmt.Errorf("unknown long flag '%s'", flagToken)
}
token, tokens = tokens.Next()
if token.Type != TokenArg {
return nil, fmt.Errorf("expected argument for flag '%s'", flagToken)
}
defaultValue = token.Value
}
if err := flag.value.Set(defaultValue); err != nil {
return nil, err
}
if flag.dispatch != nil {
if err := flag.dispatch(); err != nil {
return nil, err
}
}
default:
tokens = tokens.Return(token)
break loop
}
}
// Check that required flags were provided.
if len(remaining) == 1 {
for k := range remaining {
return nil, fmt.Errorf("required flag --%s not provided", k)
}
} else if len(remaining) > 1 {
flags := make([]string, 0, len(remaining))
for k := range remaining {
flags = append(flags, "--"+k)
}
return nil, fmt.Errorf("required flags %s not provided", strings.Join(flags, ", "))
}
return tokens, nil
}
// FlagClause is a fluid interface used to build flags.
type FlagClause struct {
parserMixin
name string
shorthand byte
help string
defaultValue string
placeholder string
dispatch Dispatch
}
func newFlag(name, help string) *FlagClause {
f := &FlagClause{
name: name,
help: help,
}
return f
}
func (f *FlagClause) formatPlaceHolder() string {
if f.placeholder != "" {
return f.placeholder
}
if f.defaultValue != "" {
if _, ok := f.value.(*stringValue); ok {
return fmt.Sprintf("%q", f.value)
}
return f.value.String()
}
return strings.ToUpper(f.name)
}
func (f *FlagClause) init() {
if f.required && f.defaultValue != "" {
panic(fmt.Sprintf("required flag '--%s' with default value that will never be used", f.name))
}
if f.value == nil {
panic(fmt.Sprintf("no value defined for --%s", f.name))
}
if f.defaultValue != "" {
if err := f.value.Set(f.defaultValue); err != nil {
panic(fmt.Sprintf("default value for --%s is invalid: %s", f.name, err))
}
}
}
// Dispatch to the given function when the flag is parsed.
func (f *FlagClause) Dispatch(dispatch Dispatch) *FlagClause {
f.dispatch = dispatch
return f
}
// Default value for this flag. It *must* be parseable by the value of the flag.
func (f *FlagClause) Default(value string) *FlagClause {
f.defaultValue = value
return f
}
// PlaceHolder sets the place-holder string used for flag values in the help. The
// default behaviour is to use the value provided by Default() if provided,
// then fall back on the capitalized flag name.
func (f *FlagClause) PlaceHolder(placeholder string) *FlagClause {
f.placeholder = placeholder
return f
}
// Required makes the flag required. You can not provide a Default() value to a Required() flag.
func (f *FlagClause) Required() *FlagClause {
f.required = true
return f
}
// Short sets the short flag name.
func (f *FlagClause) Short(name byte) *FlagClause {
f.shorthand = name
return f
}
// Bool makes this flag a boolean flag.
func (f *FlagClause) Bool() (target *bool) {
target = new(bool)
f.SetValue(newBoolValue(false, target))
return
}