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go/src/pkg/syscall/env_windows.go
Alex Brainman 04b405c7fc syscall: handle empty environment variable values properly on windows
Setenv("AN_ENV_VAR", "") deletes AN_ENV_VAR instead of setting it
to "" at this moment. Also Getenv("AN_ENV_VAR") returns "not found",
if AN_ENV_VAR is "". Change it, so they behave like unix.

Fixes #5610

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/10594043
2013-06-27 10:11:30 +10:00

83 lines
1.7 KiB
Go

// Copyright 2010 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.
// Windows environment variables.
package syscall
import (
"unicode/utf16"
"unsafe"
)
func Getenv(key string) (value string, found bool) {
keyp, err := UTF16PtrFromString(key)
if err != nil {
return "", false
}
b := make([]uint16, 100)
n, e := GetEnvironmentVariable(keyp, &b[0], uint32(len(b)))
if n == 0 && e == ERROR_ENVVAR_NOT_FOUND {
return "", false
}
if n > uint32(len(b)) {
b = make([]uint16, n)
n, e = GetEnvironmentVariable(keyp, &b[0], uint32(len(b)))
if n > uint32(len(b)) {
n = 0
}
}
return string(utf16.Decode(b[0:n])), true
}
func Setenv(key, value string) error {
v, err := UTF16PtrFromString(value)
if err != nil {
return err
}
keyp, err := UTF16PtrFromString(key)
if err != nil {
return err
}
e := SetEnvironmentVariable(keyp, v)
if e != nil {
return e
}
return nil
}
func Clearenv() {
for _, s := range Environ() {
// Environment variables can begin with =
// so start looking for the separator = at j=1.
// http://blogs.msdn.com/b/oldnewthing/archive/2010/05/06/10008132.aspx
for j := 1; j < len(s); j++ {
if s[j] == '=' {
Setenv(s[0:j], "")
break
}
}
}
}
func Environ() []string {
s, e := GetEnvironmentStrings()
if e != nil {
return nil
}
defer FreeEnvironmentStrings(s)
r := make([]string, 0, 50) // Empty with room to grow.
for from, i, p := 0, 0, (*[1 << 24]uint16)(unsafe.Pointer(s)); true; i++ {
if p[i] == 0 {
// empty string marks the end
if i <= from {
break
}
r = append(r, string(utf16.Decode(p[from:i])))
from = i + 1
}
}
return r
}