langle_separated_map_string_string.go

Documentation: k8s.io/component-base/cli/flag

     1  /*
     2  Copyright 2017 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package flag
    18  
    19  import (
    20  	"fmt"
    21  	"sort"
    22  	"strings"
    23  )
    24  
    25  // LangleSeparatedMapStringString can be set from the command line with the format `--flag "string<string"`.
    26  // Multiple comma-separated key-value pairs in a single invocation are supported. For example: `--flag "a<foo,b<bar"`.
    27  // Multiple flag invocations are supported. For example: `--flag "a<foo" --flag "b<foo"`.
    28  type LangleSeparatedMapStringString struct {
    29  	Map         *map[string]string
    30  	initialized bool // set to true after first Set call
    31  }
    32  
    33  // NewLangleSeparatedMapStringString takes a pointer to a map[string]string and returns the
    34  // LangleSeparatedMapStringString flag parsing shim for that map
    35  func NewLangleSeparatedMapStringString(m *map[string]string) *LangleSeparatedMapStringString {
    36  	return &LangleSeparatedMapStringString{Map: m}
    37  }
    38  
    39  // String implements github.com/spf13/pflag.Value
    40  func (m *LangleSeparatedMapStringString) String() string {
    41  	pairs := []string{}
    42  	for k, v := range *m.Map {
    43  		pairs = append(pairs, fmt.Sprintf("%s<%s", k, v))
    44  	}
    45  	sort.Strings(pairs)
    46  	return strings.Join(pairs, ",")
    47  }
    48  
    49  // Set implements github.com/spf13/pflag.Value
    50  func (m *LangleSeparatedMapStringString) Set(value string) error {
    51  	if m.Map == nil {
    52  		return fmt.Errorf("no target (nil pointer to map[string]string)")
    53  	}
    54  	if !m.initialized || *m.Map == nil {
    55  		// clear default values, or allocate if no existing map
    56  		*m.Map = make(map[string]string)
    57  		m.initialized = true
    58  	}
    59  	for _, s := range strings.Split(value, ",") {
    60  		if len(s) == 0 {
    61  			continue
    62  		}
    63  		arr := strings.SplitN(s, "<", 2)
    64  		if len(arr) != 2 {
    65  			return fmt.Errorf("malformed pair, expect string<string")
    66  		}
    67  		k := strings.TrimSpace(arr[0])
    68  		v := strings.TrimSpace(arr[1])
    69  		(*m.Map)[k] = v
    70  	}
    71  	return nil
    72  }
    73  
    74  // Type implements github.com/spf13/pflag.Value
    75  func (*LangleSeparatedMapStringString) Type() string {
    76  	return "mapStringString"
    77  }
    78  
    79  // Empty implements OmitEmpty
    80  func (m *LangleSeparatedMapStringString) Empty() bool {
    81  	return len(*m.Map) == 0
    82  }
    83
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