github.com/rkt/rkt@v1.30.1-0.20200224141603-171c416fac02/pkg/flag/discard.go (about)

     1  // Copyright 2016 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 "fmt"
    18  
    19  // DiscardFlag is a flag type that discards all options with a warning
    20  type DiscardFlag struct {
    21  	Name string
    22  	used bool // pflag calls .set at least once always
    23  }
    24  
    25  func NewDiscardFlag(name string) *DiscardFlag {
    26  	df := DiscardFlag{
    27  		Name: name,
    28  	}
    29  	return &df
    30  }
    31  
    32  func (df *DiscardFlag) Set(_ string) error {
    33  	fmt.Printf("Warning: -%s not supported; ignoring\n", df.Name)
    34  	return nil
    35  }
    36  
    37  func (df *DiscardFlag) String() string {
    38  	return ""
    39  }
    40  
    41  func (df *DiscardFlag) Type() string {
    42  	return "DiscardFlag"
    43  }