mirror of
https://github.com/golang/go
synced 2024-11-15 06:50:32 -07:00
8dc08394f0
The immediate reason is that we want to use godebug from math/rand, and math/rand importing godebug importing os causes an import cycle in package testing. More generally, the new approach to backward compatibility outlined in discussion #55090 will require using this package from other similarly sensitive places, perhaps even package os itself. Best to remove all dependencies. Preparation for #54880. Change-Id: Ia01657a2d90e707a8121a336c9db3b7247c0198f Reviewed-on: https://go-review.googlesource.com/c/go/+/439418 Auto-Submit: Russ Cox <rsc@golang.org> Run-TryBot: Russ Cox <rsc@golang.org> Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org>
71 lines
1.6 KiB
Go
71 lines
1.6 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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import "unsafe"
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func gogetenv(key string) string {
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env := environ()
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if env == nil {
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throw("getenv before env init")
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}
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for _, s := range env {
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if len(s) > len(key) && s[len(key)] == '=' && envKeyEqual(s[:len(key)], key) {
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return s[len(key)+1:]
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}
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}
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return ""
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}
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// envKeyEqual reports whether a == b, with ASCII-only case insensitivity
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// on Windows. The two strings must have the same length.
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func envKeyEqual(a, b string) bool {
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if GOOS == "windows" { // case insensitive
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for i := 0; i < len(a); i++ {
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ca, cb := a[i], b[i]
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if ca == cb || lowerASCII(ca) == lowerASCII(cb) {
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continue
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}
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return false
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}
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return true
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}
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return a == b
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}
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func lowerASCII(c byte) byte {
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if 'A' <= c && c <= 'Z' {
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return c + ('a' - 'A')
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}
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return c
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}
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var _cgo_setenv unsafe.Pointer // pointer to C function
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var _cgo_unsetenv unsafe.Pointer // pointer to C function
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// Update the C environment if cgo is loaded.
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func setenv_c(k string, v string) {
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if _cgo_setenv == nil {
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return
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}
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arg := [2]unsafe.Pointer{cstring(k), cstring(v)}
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asmcgocall(_cgo_setenv, unsafe.Pointer(&arg))
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}
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// Update the C environment if cgo is loaded.
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func unsetenv_c(k string) {
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if _cgo_unsetenv == nil {
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return
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}
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arg := [1]unsafe.Pointer{cstring(k)}
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asmcgocall(_cgo_unsetenv, unsafe.Pointer(&arg))
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}
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func cstring(s string) unsafe.Pointer {
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p := make([]byte, len(s)+1)
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copy(p, s)
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return unsafe.Pointer(&p[0])
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}
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