1 // Copyright 2018 The etcd Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package flags 16 17 import ( 18 "flag" 19 "fmt" 20 "sort" 21 "strings" 22 ) 23 24 // StringsValue wraps "sort.StringSlice". 25 type StringsValue sort.StringSlice 26 27 // Set parses a command line set of strings, separated by comma. 28 // Implements "flag.Value" interface. 29 func (ss *StringsValue) Set(s string) error { 30 *ss = strings.Split(s, ",") 31 return nil 32 } 33 34 // String implements "flag.Value" interface. 35 func (ss *StringsValue) String() string { return strings.Join(*ss, ",") } 36 37 // NewStringsValue implements string slice as "flag.Value" interface. 38 // Given value is to be separated by comma. 39 func NewStringsValue(s string) (ss *StringsValue) { 40 if s == "" { 41 return &StringsValue{} 42 } 43 ss = new(StringsValue) 44 if err := ss.Set(s); err != nil { 45 panic(fmt.Sprintf("new StringsValue should never fail: %v", err)) 46 } 47 return ss 48 } 49 50 // StringsFromFlag returns a string slice from the flag. 51 func StringsFromFlag(fs *flag.FlagSet, flagName string) []string { 52 return []string(*fs.Lookup(flagName).Value.(*StringsValue)) 53 } 54