flag.go

Documentation: github.com/bazelbuild/bazel-gazelle/flag

     1  // Copyright 2017 The Bazel Authors. All rights reserved.
     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 provides some general-purpose types which satisfy the
    16  // flag.Value interface.
    17  package flag
    18  
    19  import (
    20  	stdflag "flag"
    21  	"fmt"
    22  	"strings"
    23  )
    24  
    25  // MultiFlag collects repeated string flags into a slice.
    26  type MultiFlag struct {
    27  	IsSet  *bool
    28  	Values *[]string
    29  }
    30  
    31  var _ stdflag.Value = (*MultiFlag)(nil)
    32  
    33  func (m *MultiFlag) Set(v string) error {
    34  	if m.IsSet != nil && !*m.IsSet {
    35  		*m.IsSet = true
    36  		*m.Values = nil // clear any default values
    37  	}
    38  	*m.Values = append(*m.Values, v)
    39  	return nil
    40  }
    41  
    42  func (m *MultiFlag) String() string {
    43  	if m == nil || m.Values == nil {
    44  		return ""
    45  	}
    46  	return strings.Join(*m.Values, ",")
    47  }
    48  
    49  // ExplicitFlag is a string flag that tracks whether it was set.
    50  type ExplicitFlag struct {
    51  	IsSet *bool
    52  	Value *string
    53  }
    54  
    55  var _ stdflag.Value = (*ExplicitFlag)(nil)
    56  
    57  func (f *ExplicitFlag) Set(value string) error {
    58  	*f.IsSet = true
    59  	*f.Value = value
    60  	return nil
    61  }
    62  
    63  func (f *ExplicitFlag) String() string {
    64  	if f == nil || f.Value == nil {
    65  		return ""
    66  	}
    67  	return *f.Value
    68  }
    69  
    70  var _ stdflag.Value = (*AllowedStringFlag)(nil)
    71  
    72  type AllowedStringFlag struct {
    73  	Allowed []string
    74  	Value   *string
    75  }
    76  
    77  func (f *AllowedStringFlag) Set(v string) error {
    78  	for _, a := range f.Allowed {
    79  		if v == a {
    80  			*f.Value = v
    81  			return nil
    82  		}
    83  	}
    84  	return fmt.Errorf("Invalid argument %q. Possible values are: %s", v, strings.Join(f.Allowed, ", "))
    85  }
    86  
    87  func (f *AllowedStringFlag) String() string {
    88  	if f == nil || f.Value == nil {
    89  		return ""
    90  	}
    91  	return *f.Value
    92  }
    93
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