go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/common/flag/strpairs.go (about)

     1  // Copyright 2018 The LUCI 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  	"flag"
    19  	"fmt"
    20  	"strings"
    21  
    22  	"go.chromium.org/luci/common/data/strpair"
    23  )
    24  
    25  // strpairsFlag implements the flag.Getter returned by StrPairs.
    26  type stringPairsFlag strpair.Map
    27  
    28  // StringPairs returns a flag.Getter for parsing strpair.Map from a
    29  // a set of colon-separated strings.
    30  // Example:
    31  //
    32  //	"-f a:1"
    33  //	"-f a:2"
    34  //	"-f b:3:3" (The value contains a colon ":")
    35  //
    36  // Panics if m is nil.
    37  func StringPairs(m strpair.Map) flag.Getter {
    38  	if m == nil {
    39  		panic("m is nil")
    40  	}
    41  	return stringPairsFlag(m)
    42  }
    43  
    44  // String implements the flag.Value interface.
    45  func (f stringPairsFlag) String() string {
    46  	return strings.Join(strpair.Map(f).Format(), ", ")
    47  }
    48  
    49  // Set implements the flag.Value interface.
    50  func (f stringPairsFlag) Set(s string) error {
    51  	// Splits the string into at most two parts by the first colon ":" because
    52  	// the value part might contain a colon ":".
    53  	parts := strings.SplitN(s, ":", 2)
    54  	if len(parts) == 1 {
    55  		return fmt.Errorf("no colon")
    56  	}
    57  	strpair.Map(f).Add(parts[0], parts[1])
    58  	return nil
    59  }
    60  
    61  // Get retrieves the flag value.
    62  func (f stringPairsFlag) Get() any {
    63  	return strpair.Map(f)
    64  }