go.etcd.io/etcd@v3.3.27+incompatible/pkg/flags/strings.go (about)

     1  // Copyright 2015 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  	"errors"
    19  	"flag"
    20  	"sort"
    21  	"strings"
    22  )
    23  
    24  // NewStringsFlag creates a new string flag for which any one of the given
    25  // strings is a valid value, and any other value is an error.
    26  //
    27  // valids[0] will be default value. Caller must be sure len(valids)!=0 or
    28  // it will panic.
    29  func NewStringsFlag(valids ...string) *StringsFlag {
    30  	return &StringsFlag{Values: valids, val: valids[0]}
    31  }
    32  
    33  // StringsFlag implements the flag.Value interface.
    34  type StringsFlag struct {
    35  	Values []string
    36  	val    string
    37  }
    38  
    39  // Set verifies the argument to be a valid member of the allowed values
    40  // before setting the underlying flag value.
    41  func (ss *StringsFlag) Set(s string) error {
    42  	for _, v := range ss.Values {
    43  		if s == v {
    44  			ss.val = s
    45  			return nil
    46  		}
    47  	}
    48  	return errors.New("invalid value")
    49  }
    50  
    51  // String returns the set value (if any) of the StringsFlag
    52  func (ss *StringsFlag) String() string {
    53  	return ss.val
    54  }
    55  
    56  // StringsValueV2 wraps "sort.StringSlice".
    57  type StringsValueV2 sort.StringSlice
    58  
    59  // Set parses a command line set of strings, separated by comma.
    60  // Implements "flag.Value" interface.
    61  func (ss *StringsValueV2) Set(s string) error {
    62  	*ss = strings.Split(s, ",")
    63  	return nil
    64  }
    65  
    66  // String implements "flag.Value" interface.
    67  func (ss *StringsValueV2) String() string { return strings.Join(*ss, ",") }
    68  
    69  // NewStringsValueV2 implements string slice as "flag.Value" interface.
    70  // Given value is to be separated by comma.
    71  func NewStringsValueV2(s string) (ss *StringsValueV2) {
    72  	if s == "" {
    73  		return &StringsValueV2{}
    74  	}
    75  	ss = new(StringsValueV2)
    76  	if err := ss.Set(s); err != nil {
    77  		plog.Panicf("new StringsValueV2 should never fail: %v", err)
    78  	}
    79  	return ss
    80  }
    81  
    82  // StringsFromFlagV2 returns a string slice from the flag.
    83  func StringsFromFlagV2(fs *flag.FlagSet, flagName string) []string {
    84  	return []string(*fs.Lookup(flagName).Value.(*StringsValueV2))
    85  }