| // 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 os |
| |
| import ( |
| "syscall" |
| "utf16" |
| "unsafe" |
| ) |
| |
| // ENOENV is the Error indicating that an environment variable does not exist. |
| var ENOENV = NewError("no such environment variable") |
| |
| // 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) { |
| b := make([]uint16, 100) |
| n, e := syscall.GetEnvironmentVariable(syscall.StringToUTF16Ptr(key), &b[0], uint32(len(b))) |
| if n == 0 && e == syscall.ERROR_ENVVAR_NOT_FOUND { |
| return "", ENOENV |
| } |
| if n > uint32(len(b)) { |
| b = make([]uint16, n) |
| n, e = syscall.GetEnvironmentVariable(syscall.StringToUTF16Ptr(key), &b[0], uint32(len(b))) |
| if n > uint32(len(b)) { |
| n = 0 |
| } |
| } |
| if n == 0 { |
| return "", NewSyscallError("GetEnvironmentVariable", e) |
| } |
| return string(utf16.Decode(b[0:n])), 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 { |
| var v *uint16 |
| if len(value) > 0 { |
| v = syscall.StringToUTF16Ptr(value) |
| } |
| ok, e := syscall.SetEnvironmentVariable(syscall.StringToUTF16Ptr(key), v) |
| if !ok { |
| return NewSyscallError("SetEnvironmentVariable", e) |
| } |
| return nil |
| } |
| |
| // Clearenv deletes all environment variables. |
| 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 |
| } |
| } |
| } |
| } |
| |
| // Environ returns an array of strings representing the environment, |
| // in the form "key=value". |
| func Environ() []string { |
| s, e := syscall.GetEnvironmentStrings() |
| if e != 0 { |
| return nil |
| } |
| defer syscall.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 |
| } |
| |
| // TempDir returns the default directory to use for temporary files. |
| func TempDir() string { |
| const pathSep = '\\' |
| dirw := make([]uint16, syscall.MAX_PATH) |
| n, _ := syscall.GetTempPath(uint32(len(dirw)), &dirw[0]) |
| if n > uint32(len(dirw)) { |
| dirw = make([]uint16, n) |
| n, _ = syscall.GetTempPath(uint32(len(dirw)), &dirw[0]) |
| if n > uint32(len(dirw)) { |
| n = 0 |
| } |
| } |
| if n > 0 && dirw[n-1] == pathSep { |
| n-- |
| } |
| return string(utf16.Decode(dirw[0:n])) |
| } |