github.com/westcoastroms/westcoastroms-build@v0.0.0-20190928114312-2350e5a73030/build/soong/env/env.go (about)

     1  // Copyright 2015 Google Inc. 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  // env implements the environment JSON file handling for the soong_env command line tool run before
    16  // the builder and for the env writer in the builder.
    17  package env
    18  
    19  import (
    20  	"encoding/json"
    21  	"fmt"
    22  	"io/ioutil"
    23  	"os"
    24  	"sort"
    25  )
    26  
    27  type envFileEntry struct{ Key, Value string }
    28  type envFileData []envFileEntry
    29  
    30  func WriteEnvFile(filename string, envDeps map[string]string) error {
    31  	contents := make(envFileData, 0, len(envDeps))
    32  	for key, value := range envDeps {
    33  		contents = append(contents, envFileEntry{key, value})
    34  	}
    35  
    36  	sort.Sort(contents)
    37  
    38  	data, err := json.MarshalIndent(contents, "", "    ")
    39  	if err != nil {
    40  		return err
    41  	}
    42  
    43  	data = append(data, '\n')
    44  
    45  	err = ioutil.WriteFile(filename, data, 0664)
    46  	if err != nil {
    47  		return err
    48  	}
    49  
    50  	return nil
    51  }
    52  
    53  func StaleEnvFile(filename string) (bool, error) {
    54  	data, err := ioutil.ReadFile(filename)
    55  	if err != nil {
    56  		return true, err
    57  	}
    58  
    59  	var contents envFileData
    60  
    61  	err = json.Unmarshal(data, &contents)
    62  	if err != nil {
    63  		return true, err
    64  	}
    65  
    66  	var changed []string
    67  	for _, entry := range contents {
    68  		key := entry.Key
    69  		old := entry.Value
    70  		cur := os.Getenv(key)
    71  		if old != cur {
    72  			changed = append(changed, fmt.Sprintf("%s (%q -> %q)", key, old, cur))
    73  		}
    74  	}
    75  
    76  	if len(changed) > 0 {
    77  		fmt.Printf("environment variables changed value:\n")
    78  		for _, s := range changed {
    79  			fmt.Printf("   %s\n", s)
    80  		}
    81  		return true, nil
    82  	}
    83  
    84  	return false, nil
    85  }
    86  
    87  func (e envFileData) Len() int {
    88  	return len(e)
    89  }
    90  
    91  func (e envFileData) Less(i, j int) bool {
    92  	return e[i].Key < e[j].Key
    93  }
    94  
    95  func (e envFileData) Swap(i, j int) {
    96  	e[i], e[j] = e[j], e[i]
    97  }