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// Copyright 2016 The LUCI Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package flag
import (
"flag"
"fmt"
"sort"
"strings"
"go.chromium.org/luci/common/errors"
)
type strMapFlag map[string]string
// StringMap returns a flag.Getter for parsing map[string]string from a
// a set of colon-separated strings.
// Example:
// -f a:1 -f b:3
// The flag.Getter.Set implementation returns an error if the key is already
// in the map.
// Panics if m is nil.
func StringMap(m map[string]string) flag.Getter {
if m == nil {
panic("m is nil")
}
return strMapFlag(m)
}
func (f strMapFlag) String() string {
// This encoding is lossy. It is optimized for readability.
pairs := make([]string, 0, len(f))
for k, v := range f {
pairs = append(pairs, fmt.Sprintf("%s:%s", k, v))
}
sort.Strings(pairs)
return strings.Join(pairs, " ")
}
func (f strMapFlag) Set(s string) error {
parts := strings.Split(s, ":")
if len(parts) == 1 {
return fmt.Errorf("no colon")
}
key := parts[0]
value := parts[1]
if _, ok := f[key]; ok {
return errors.Reason("key %q is already specified", key).Err()
}
f[key] = value
return nil
}
func (f strMapFlag) Get() interface{} {
return map[string]string(f)
}