spf13--viper/flags.go
David Calavera 66249a6550 Add FlagValue interface to support other flag systems.
Using an interface allows people to use their favourite flag system
with viper without being restricted to the semantics of pflag or the
standard library.

This change introduce two new functions `BindFlagValues` and
`BindFlagValue` that behave like `BindFlags` and `BindFlag` but using
the new interface as values.

This change also introduces two internal structures to transform
`*pflag.FlagSet` and `*pflag.Flag` into the new interface. This way,
viper keeps working as expected for people that are currently using the
pflag package without breaking backwards compatibility.

Signed-off-by: David Calavera <david.calavera@gmail.com>
2015-12-24 10:16:41 -05:00

57 lines
1.3 KiB
Go

package viper
import "github.com/spf13/pflag"
// FlagValueSet is an interface that users can implement
// to bind a set of flags to viper.
type FlagValueSet interface {
VisitAll(fn func(FlagValue))
}
// FlagValue is an interface that users can implement
// to bind different flags to viper.
type FlagValue interface {
HasChanged() bool
Name() string
ValueString() string
ValueType() string
}
// pflagValueSet is a wrapper around *pflag.ValueSet
// that implements FlagValueSet.
type pflagValueSet struct {
flags *pflag.FlagSet
}
// VisitAll iterates over all *pflag.Flag inside the *pflag.FlagSet.
func (p pflagValueSet) VisitAll(fn func(flag FlagValue)) {
p.flags.VisitAll(func(flag *pflag.Flag) {
fn(pflagValue{flag})
})
}
// pflagValue is a wrapper aroung *pflag.flag
// that implements FlagValue
type pflagValue struct {
flag *pflag.Flag
}
// HasChanges returns whether the flag has changes or not.
func (p pflagValue) HasChanged() bool {
return p.flag.Changed
}
// Name returns the name of the flag.
func (p pflagValue) Name() string {
return p.flag.Name
}
// ValueString returns the value of the flag as a string.
func (p pflagValue) ValueString() string {
return p.flag.Value.String()
}
// ValueType returns the type of the flag as a string.
func (p pflagValue) ValueType() string {
return p.flag.Value.Type()
}