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// 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.
package exec
import (
"errors"
"os"
"strings"
)
// ErrNotFound is the error resulting if a path search failed to find an executable file.
var ErrNotFound = errors.New("executable file not found in %PATH%")
func chkStat(file string) error {
d, err := os.Stat(file)
if err != nil {
return err
}
if d.IsDir() {
return os.EPERM
}
return nil
}
func findExecutable(file string, exts []string) (string, error) {
if len(exts) == 0 {
return file, chkStat(file)
}
f := strings.ToLower(file)
for _, e := range exts {
if strings.HasSuffix(f, e) {
return file, chkStat(file)
}
}
for _, e := range exts {
if f := file + e; chkStat(f) == nil {
return f, nil
}
}
return ``, os.ENOENT
}
func LookPath(file string) (f string, err error) {
x := os.Getenv(`PATHEXT`)
if x == `` {
x = `.COM;.EXE;.BAT;.CMD`
}
exts := []string{}
for _, e := range strings.Split(strings.ToLower(x), `;`) {
if e == "" {
continue
}
if e[0] != '.' {
e = "." + e
}
exts = append(exts, e)
}
if strings.IndexAny(file, `:\/`) != -1 {
if f, err = findExecutable(file, exts); err == nil {
return
}
return ``, &Error{file, err}
}
if pathenv := os.Getenv(`PATH`); pathenv == `` {
if f, err = findExecutable(`.\`+file, exts); err == nil {
return
}
} else {
for _, dir := range strings.Split(pathenv, `;`) {
if f, err = findExecutable(dir+`\`+file, exts); err == nil {
return
}
}
}
return ``, &Error{file, ErrNotFound}
}
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