metrics-server/vendor/k8s.io/apiserver/pkg/util/flag/tristate.go

/*
Copyright 2014 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package flag

import (
	"fmt"
	"strconv"
)

// Tristate is a flag compatible with flags and pflags that
// keeps track of whether it had a value supplied or not.
type Tristate int

const (
	Unset Tristate = iota // 0
	True
	False
)

func (f *Tristate) Default(value bool) {
	*f = triFromBool(value)
}

func (f Tristate) String() string {
	b := boolFromTri(f)
	return fmt.Sprintf("%t", b)
}

func (f Tristate) Value() bool {
	b := boolFromTri(f)
	return b
}

func (f *Tristate) Set(value string) error {
	boolVal, err := strconv.ParseBool(value)
	if err != nil {
		return err
	}

	*f = triFromBool(boolVal)
	return nil
}

func (f Tristate) Provided() bool {
	if f != Unset {
		return true
	}
	return false
}

func (f *Tristate) Type() string {
	return "tristate"
}

func boolFromTri(t Tristate) bool {
	if t == True {
		return true
	} else {
		return false
	}
}

func triFromBool(b bool) Tristate {
	if b {
		return True
	} else {
		return False
	}
}