github.com/blixtra/rkt@v0.8.1-0.20160204105720-ab0d1add1a43/rkt/flag/optionlist.go (about)

     1  // Copyright 2015 The rkt 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 flag
    16  
    17  import (
    18  	"errors"
    19  	"fmt"
    20  	"strings"
    21  
    22  	"github.com/hashicorp/errwrap"
    23  	"github.com/spf13/pflag"
    24  )
    25  
    26  // OptionList is a flag value type supporting a csv list of options
    27  type OptionList struct {
    28  	// Options field holds all specified and valid options. Should
    29  	// not be modified.
    30  	Options     []string
    31  	allOptions  []string
    32  	permissible map[string]struct{}
    33  	typeName    string
    34  }
    35  
    36  var _ pflag.Value = (*OptionList)(nil)
    37  
    38  func NewOptionList(permissibleOptions []string, defaultOptions string) (*OptionList, error) {
    39  	permissible := make(map[string]struct{})
    40  	ol := &OptionList{
    41  		allOptions:  permissibleOptions,
    42  		permissible: permissible,
    43  		typeName:    "optionList",
    44  	}
    45  
    46  	for _, o := range permissibleOptions {
    47  		ol.permissible[o] = struct{}{}
    48  	}
    49  
    50  	if err := ol.Set(defaultOptions); err != nil {
    51  		return nil, errwrap.Wrap(errors.New("problem setting defaults"), err)
    52  	}
    53  
    54  	return ol, nil
    55  }
    56  
    57  func (ol *OptionList) Set(s string) error {
    58  	ol.Options = nil
    59  	if s == "" {
    60  		return nil
    61  	}
    62  	options := strings.Split(strings.ToLower(s), ",")
    63  	seen := map[string]struct{}{}
    64  	for _, o := range options {
    65  		if _, ok := ol.permissible[o]; !ok {
    66  			return fmt.Errorf("unknown option %q", o)
    67  		}
    68  		if _, ok := seen[o]; ok {
    69  			return fmt.Errorf("duplicated option %q", o)
    70  		}
    71  		ol.Options = append(ol.Options, o)
    72  		seen[o] = struct{}{}
    73  	}
    74  
    75  	return nil
    76  }
    77  
    78  func (ol *OptionList) String() string {
    79  	return strings.Join(ol.Options, ",")
    80  }
    81  
    82  func (ol *OptionList) Type() string {
    83  	return ol.typeName
    84  }
    85  
    86  func (ol *OptionList) PermissibleString() string {
    87  	return fmt.Sprintf(`"%s"`, strings.Join(ol.allOptions, `", "`))
    88  }