// Copyright 2016 VMware, Inc. All Rights Reserved.
//
// 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 flags

import (
	"flag"
)

type optionalString struct {
	val **string
}

func (b *optionalString) Set(s string) error {
	*b.val = &s
	return nil
}

func (b *optionalString) Get() interface{} {
	if *b.val == nil {
		return nil
	}
	return **b.val
}

func (b *optionalString) String() string {
	if b.val == nil || *b.val == nil {
		return "<nil>"
	}
	return **b.val
}

func (b *optionalString) IsBoolFlag() bool { return false }

// NewOptionalString returns a flag.Value implementation where there is no default value.
// This avoids sending a default value over the wire as using flag.StringVar() would.
func NewOptionalString(s **string) flag.Value {
	return &optionalString{s}
}