src/lib/os/env.go

// 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";
	"os";
)

var (
	ENOENV = NewError("no such environment variable");

	env map[string] string;
)

func copyenv() {
	env = make(map[string] string);
	for i, s := range sys.Envs {
		for j := 0; j < len(s); j++ {
			if s[j] == '=' {
				env[s[0:j]] = s[j+1:len(s)];
				break;
			}
		}
	}
}

func Getenv(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;
}

func Setenv(key, value string) *Error {
	once.Do(copyenv);

	if len(key) == 0 {
		return EINVAL;
	}
	env[key] = value;
	return nil;
}

func Clearenv() {
	once.Do(copyenv);	// prevent copyenv in Getenv/Setenv
	env = make(map[string] string);
}

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];
}