os.go

package main

import (
	"errors"
	"os"
	"runtime"
)

// os.UserHomeDir() is implemented in
// https://go-review.googlesource.com/c/go/+/139418 so implement here for now
func userHomeDir() (string, error) {
	env, enverr := "HOME", "$HOME"
	switch runtime.GOOS {
	case "windows":
		env, enverr = "USERPROFILE", "%userprofile%"
	case "plan9":
		env, enverr = "home", "$home"
	case "nacl", "android":
		return "/", nil
	case "darwin":
		if runtime.GOARCH == "arm" || runtime.GOARCH == "arm64" {
			return "/", nil
		}
	}
	if v := os.Getenv(env); v != "" {
		return v, nil
	}
	return "", errors.New(enverr + " is not defined")
}