1// Copyright 2009 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package pflag
6
7import (
8 goflag "flag"
9 "reflect"
10 "strings"
11)
12
13// flagValueWrapper implements pflag.Value around a flag.Value. The main
14// difference here is the addition of the Type method that returns a string
15// name of the type. As this is generally unknown, we approximate that with
16// reflection.
17type flagValueWrapper struct {
18 inner goflag.Value
19 flagType string
20}
21
22// We are just copying the boolFlag interface out of goflag as that is what
23// they use to decide if a flag should get "true" when no arg is given.
24type goBoolFlag interface {
25 goflag.Value
26 IsBoolFlag() bool
27}
28
29func wrapFlagValue(v goflag.Value) Value {
30 // If the flag.Value happens to also be a pflag.Value, just use it directly.
31 if pv, ok := v.(Value); ok {
32 return pv
33 }
34
35 pv := &flagValueWrapper{
36 inner: v,
37 }
38
39 t := reflect.TypeOf(v)
40 if t.Kind() == reflect.Interface || t.Kind() == reflect.Ptr {
41 t = t.Elem()
42 }
43
44 pv.flagType = strings.TrimSuffix(t.Name(), "Value")
45 return pv
46}
47
48func (v *flagValueWrapper) String() string {
49 return v.inner.String()
50}
51
52func (v *flagValueWrapper) Set(s string) error {
53 return v.inner.Set(s)
54}
55
56func (v *flagValueWrapper) Type() string {
57 return v.flagType
58}
59
60// PFlagFromGoFlag will return a *pflag.Flag given a *flag.Flag
61// If the *flag.Flag.Name was a single character (ex: `v`) it will be accessiblei
62// with both `-v` and `--v` in flags. If the golang flag was more than a single
63// character (ex: `verbose`) it will only be accessible via `--verbose`
64func PFlagFromGoFlag(goflag *goflag.Flag) *Flag {
65 // Remember the default value as a string; it won't change.
66 flag := &Flag{
67 Name: goflag.Name,
68 Usage: goflag.Usage,
69 Value: wrapFlagValue(goflag.Value),
70 // Looks like golang flags don't set DefValue correctly :-(
71 //DefValue: goflag.DefValue,
72 DefValue: goflag.Value.String(),
73 }
74 // Ex: if the golang flag was -v, allow both -v and --v to work
75 if len(flag.Name) == 1 {
76 flag.Shorthand = flag.Name
77 }
78 if fv, ok := goflag.Value.(goBoolFlag); ok && fv.IsBoolFlag() {
79 flag.NoOptDefVal = "true"
80 }
81 return flag
82}
83
84// AddGoFlag will add the given *flag.Flag to the pflag.FlagSet
85func (f *FlagSet) AddGoFlag(goflag *goflag.Flag) {
86 if f.Lookup(goflag.Name) != nil {
87 return
88 }
89 newflag := PFlagFromGoFlag(goflag)
90 f.AddFlag(newflag)
91}
92
93// AddGoFlagSet will add the given *flag.FlagSet to the pflag.FlagSet
94func (f *FlagSet) AddGoFlagSet(newSet *goflag.FlagSet) {
95 if newSet == nil {
96 return
97 }
98 newSet.VisitAll(func(goflag *goflag.Flag) {
99 f.AddGoFlag(goflag)
100 })
101 if f.addedGoFlagSets == nil {
102 f.addedGoFlagSets = make([]*goflag.FlagSet, 0)
103 }
104 f.addedGoFlagSets = append(f.addedGoFlagSets, newSet)
105}