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// Copyright 2013 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.
package vcs
import (
"os"
"strings"
)
// envForDir returns a copy of the environment
// suitable for running in the given directory.
// The environment is the current process's environment
// but with an updated $PWD, so that an os.Getwd in the
// child will be faster.
func envForDir(dir string) []string {
env := os.Environ()
// Internally we only use rooted paths, so dir is rooted.
// Even if dir is not rooted, no harm done.
return mergeEnvLists([]string{"PWD=" + dir}, env)
}
// mergeEnvLists merges the two environment lists such that
// variables with the same name in "in" replace those in "out".
func mergeEnvLists(in, out []string) []string {
NextVar:
for _, inkv := range in {
k := strings.SplitAfterN(inkv, "=", 2)[0]
for i, outkv := range out {
if strings.HasPrefix(outkv, k) {
out[i] = inkv
continue NextVar
}
}
out = append(out, inkv)
}
return out
}