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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Environment variables.
package os
import (
"once";
)
// ENOENV is the Error indicating that an environment variable does not exist.
var ENOENV = NewError("no such environment variable");
var env map[string] string;
func copyenv() {
env = make(map[string] string);
for _, s := range Envs {
for j := 0; j < len(s); j++ {
if s[j] == '=' {
env[s[0:j]] = s[j+1:len(s)];
break;
}
}
}
}
// Getenverror retrieves the value of the environment variable named by the key.
// It returns the value and an error, if any.
func Getenverror(key string) (value string, err Error) {
once.Do(copyenv);
if len(key) == 0 {
return "", EINVAL;
}
v, ok := env[key];
if !ok {
return "", ENOENV;
}
return v, nil;
}
// Getenv retrieves the value of the environment variable named by the key.
// It returns the value, which will be empty if the variable is not present.
func Getenv(key string) string {
v, _ := Getenverror(key);
return v;
}
// Setenv sets the value of the environment variable named by the key.
// It returns an Error, if any.
func Setenv(key, value string) Error {
once.Do(copyenv);
if len(key) == 0 {
return EINVAL;
}
env[key] = value;
return nil;
}
// Clearenv deletes all environment variables.
func Clearenv() {
once.Do(copyenv); // prevent copyenv in Getenv/Setenv
env = make(map[string] string);
}
// Environ returns an array of strings representing the environment,
// in the form "key=value".
func Environ() []string {
once.Do(copyenv);
a := make([]string, len(env));
i := 0;
for k, v := range env {
// check i < len(a) for safety,
// in case env is changing underfoot.
if i < len(a) {
a[i] = k + "=" + v;
i++;
}
}
return a[0:i];
}