github.com/vmware/govmomi@v0.43.0/govc/flags/optional_string.go (about) 1 /* 2 Copyright (c) 2023-2023 VMware, Inc. All Rights Reserved. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package flags 18 19 import ( 20 "flag" 21 ) 22 23 type optionalString struct { 24 val **string 25 } 26 27 func (s *optionalString) Set(input string) error { 28 *s.val = &input 29 return nil 30 } 31 32 func (s *optionalString) Get() interface{} { 33 if *s.val == nil { 34 return nil 35 } 36 return **s.val 37 } 38 39 func (s *optionalString) String() string { 40 if s.val == nil || *s.val == nil { 41 return "<nil>" 42 } 43 return **s.val 44 } 45 46 // NewOptionalString returns a flag.Value implementation where there is no default value. 47 // This avoids sending a default value over the wire as using flag.StringVar() would. 48 func NewOptionalString(v **string) flag.Value { 49 return &optionalString{v} 50 }