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Dan Willemsen1e704462016-08-21 15:17:17 -07001// Copyright 2017 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
15package build
16
17import (
18 "bufio"
19 "fmt"
20 "io"
21 "os"
22 "strings"
23)
24
25// Environment adds a number of useful manipulation functions to the list of
26// strings returned by os.Environ() and used in exec.Cmd.Env.
27type Environment []string
28
29// OsEnvironment wraps the current environment returned by os.Environ()
30func OsEnvironment() *Environment {
31 env := Environment(os.Environ())
32 return &env
33}
34
35// Get returns the value associated with the key, and whether it exists.
36// It's equivalent to the os.LookupEnv function, but with this copy of the
37// Environment.
38func (e *Environment) Get(key string) (string, bool) {
39 for _, env := range *e {
40 if k, v, ok := decodeKeyValue(env); ok && k == key {
41 return v, true
42 }
43 }
44 return "", false
45}
46
47// Set sets the value associated with the key, overwriting the current value
48// if it exists.
49func (e *Environment) Set(key, value string) {
50 e.Unset(key)
51 *e = append(*e, key+"="+value)
52}
53
54// Unset removes the specified keys from the Environment.
55func (e *Environment) Unset(keys ...string) {
56 out := (*e)[:0]
57 for _, env := range *e {
58 if key, _, ok := decodeKeyValue(env); ok && inList(key, keys) {
59 continue
60 }
61 out = append(out, env)
62 }
63 *e = out
64}
65
Dan Willemsened869522018-01-08 14:58:46 -080066// UnsetWithPrefix removes all keys that start with prefix.
67func (e *Environment) UnsetWithPrefix(prefix string) {
68 out := (*e)[:0]
69 for _, env := range *e {
70 if key, _, ok := decodeKeyValue(env); ok && strings.HasPrefix(key, prefix) {
71 continue
72 }
73 out = append(out, env)
74 }
75 *e = out
76}
77
Dan Willemsenfb1271a2018-09-26 15:00:42 -070078// Allow removes all keys that are not present in the input list
79func (e *Environment) Allow(keys ...string) {
80 out := (*e)[:0]
81 for _, env := range *e {
82 if key, _, ok := decodeKeyValue(env); ok && inList(key, keys) {
83 out = append(out, env)
84 }
85 }
86 *e = out
87}
88
Dan Willemsen1e704462016-08-21 15:17:17 -070089// Environ returns the []string required for exec.Cmd.Env
90func (e *Environment) Environ() []string {
91 return []string(*e)
92}
93
94// Copy returns a copy of the Environment so that independent changes may be made.
95func (e *Environment) Copy() *Environment {
96 ret := Environment(make([]string, len(*e)))
97 for i, v := range *e {
98 ret[i] = v
99 }
100 return &ret
101}
102
103// IsTrue returns whether an environment variable is set to a positive value (1,y,yes,on,true)
104func (e *Environment) IsEnvTrue(key string) bool {
105 if value, ok := e.Get(key); ok {
106 return value == "1" || value == "y" || value == "yes" || value == "on" || value == "true"
107 }
108 return false
109}
110
111// IsFalse returns whether an environment variable is set to a negative value (0,n,no,off,false)
112func (e *Environment) IsFalse(key string) bool {
113 if value, ok := e.Get(key); ok {
114 return value == "0" || value == "n" || value == "no" || value == "off" || value == "false"
115 }
116 return false
117}
118
119// AppendFromKati reads a shell script written by Kati that exports or unsets
120// environment variables, and applies those to the local Environment.
121func (e *Environment) AppendFromKati(filename string) error {
122 file, err := os.Open(filename)
123 if err != nil {
124 return err
125 }
126 defer file.Close()
127
128 return e.appendFromKati(file)
129}
130
131func (e *Environment) appendFromKati(reader io.Reader) error {
132 scanner := bufio.NewScanner(reader)
133 for scanner.Scan() {
134 text := strings.TrimSpace(scanner.Text())
135
136 if len(text) == 0 || text[0] == '#' {
137 continue
138 }
139
140 cmd := strings.SplitN(text, " ", 2)
141 if len(cmd) != 2 {
142 return fmt.Errorf("Unknown kati environment line: %q", text)
143 }
144
145 if cmd[0] == "unset" {
146 str, ok := singleUnquote(cmd[1])
147 if !ok {
Dan Willemsen59339a22018-07-22 21:18:45 -0700148 return fmt.Errorf("Failed to unquote kati line: %q", text)
Dan Willemsen1e704462016-08-21 15:17:17 -0700149 }
150 e.Unset(str)
151 } else if cmd[0] == "export" {
152 key, value, ok := decodeKeyValue(cmd[1])
153 if !ok {
154 return fmt.Errorf("Failed to parse export: %v", cmd)
155 }
156
157 key, ok = singleUnquote(key)
158 if !ok {
159 return fmt.Errorf("Failed to unquote kati line: %q", text)
160 }
161 value, ok = singleUnquote(value)
162 if !ok {
163 return fmt.Errorf("Failed to unquote kati line: %q", text)
164 }
165
166 e.Set(key, value)
167 } else {
168 return fmt.Errorf("Unknown kati environment command: %q", text)
169 }
170 }
171 if err := scanner.Err(); err != nil {
172 return err
173 }
174 return nil
175}