github.com/rkt/rkt@v1.30.1-0.20200224141603-171c416fac02/tools/depsgen/util.go (about)

     1  // Copyright 2015 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 main
    16  
    17  import (
    18  	"flag"
    19  	"os"
    20  	"path/filepath"
    21  	"strings"
    22  
    23  	"github.com/rkt/rkt/tools/common"
    24  )
    25  
    26  // toMap creates a map from passed strings. This function expects an
    27  // even number of strings, otherwise it will bail out. Odd (first,
    28  // third and so on) strings are keys, even (second, fourth and so on)
    29  // strings are values.
    30  func toMap(kv ...string) map[string]string {
    31  	if len(kv)%2 != 0 {
    32  		common.Die("Expected even number of strings in toMap")
    33  	}
    34  	r := make(map[string]string, len(kv))
    35  	lastKey := ""
    36  	for i, kv := range kv {
    37  		if i%2 == 0 {
    38  			lastKey = kv
    39  		} else {
    40  			r[lastKey] = kv
    41  		}
    42  	}
    43  	return r
    44  }
    45  
    46  // appName returns application name, like depsgen
    47  func appName() string {
    48  	return filepath.Base(os.Args[0])
    49  }
    50  
    51  // replacePlaceholders replaces placeholders with values in kv in
    52  // initial str. Placeholders are in form of !!!FOO!!!, but those
    53  // passed here should be without exclamation marks.
    54  func replacePlaceholders(str string, kv ...string) string {
    55  	for ph, value := range toMap(kv...) {
    56  		str = strings.Replace(str, "!!!"+ph+"!!!", value, -1)
    57  	}
    58  	return str
    59  }
    60  
    61  // standardFlags returns a new flag set with target flag already set up
    62  func standardFlags(cmd string) (*flag.FlagSet, *string) {
    63  	f := flag.NewFlagSet(appName()+" "+cmd, flag.ExitOnError)
    64  	target := f.String("target", "", "Make target (example: $(FOO_BINARY))")
    65  	return f, target
    66  }