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