Xray-core/common/common.go

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// Package common contains common utilities that are shared among other packages.
// See each sub-package for detail.
package common
import (
"fmt"
"go/build"
"io/ioutil"
"os"
"path/filepath"
"strings"
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"github.com/xtls/xray-core/common/errors"
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)
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//go:generate go run github.com/xtls/xray-core/common/errors/errorgen
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var (
// ErrNoClue is for the situation that existing information is not enough to make a decision. For example, Router may return this error when there is no suitable route.
ErrNoClue = errors.New("not enough information for making a decision")
)
// Must panics if err is not nil.
func Must(err error) {
if err != nil {
panic(err)
}
}
// Must2 panics if the second parameter is not nil, otherwise returns the first parameter.
func Must2(v interface{}, err error) interface{} {
Must(err)
return v
}
// Error2 returns the err from the 2nd parameter.
func Error2(v interface{}, err error) error {
return err
}
// envFile returns the name of the Go environment configuration file.
// Copy from https://github.com/golang/go/blob/c4f2a9788a7be04daf931ac54382fbe2cb754938/src/cmd/go/internal/cfg/cfg.go#L150-L166
func envFile() (string, error) {
if file := os.Getenv("GOENV"); file != "" {
if file == "off" {
return "", fmt.Errorf("GOENV=off")
}
return file, nil
}
dir, err := os.UserConfigDir()
if err != nil {
return "", err
}
if dir == "" {
return "", fmt.Errorf("missing user-config dir")
}
return filepath.Join(dir, "go", "env"), nil
}
// GetRuntimeEnv returns the value of runtime environment variable,
// that is set by running following command: `go env -w key=value`.
func GetRuntimeEnv(key string) (string, error) {
file, err := envFile()
if err != nil {
return "", err
}
if file == "" {
return "", fmt.Errorf("missing runtime env file")
}
var data []byte
var runtimeEnv string
data, readErr := ioutil.ReadFile(file)
if readErr != nil {
return "", readErr
}
envStrings := strings.Split(string(data), "\n")
for _, envItem := range envStrings {
envItem = strings.TrimSuffix(envItem, "\r")
envKeyValue := strings.Split(envItem, "=")
if strings.EqualFold(strings.TrimSpace(envKeyValue[0]), key) {
runtimeEnv = strings.TrimSpace(envKeyValue[1])
}
}
return runtimeEnv, nil
}
// GetGOBIN returns GOBIN environment variable as a string. It will NOT be empty.
func GetGOBIN() string {
// The one set by user explicitly by `export GOBIN=/path` or `env GOBIN=/path command`
GOBIN := os.Getenv("GOBIN")
if GOBIN == "" {
var err error
// The one set by user by running `go env -w GOBIN=/path`
GOBIN, err = GetRuntimeEnv("GOBIN")
if err != nil {
// The default one that Golang uses
return filepath.Join(build.Default.GOPATH, "bin")
}
if GOBIN == "" {
return filepath.Join(build.Default.GOPATH, "bin")
}
return GOBIN
}
return GOBIN
}
// GetGOPATH returns GOPATH environment variable as a string. It will NOT be empty.
func GetGOPATH() string {
// The one set by user explicitly by `export GOPATH=/path` or `env GOPATH=/path command`
GOPATH := os.Getenv("GOPATH")
if GOPATH == "" {
var err error
// The one set by user by running `go env -w GOPATH=/path`
GOPATH, err = GetRuntimeEnv("GOPATH")
if err != nil {
// The default one that Golang uses
return build.Default.GOPATH
}
if GOPATH == "" {
return build.Default.GOPATH
}
return GOPATH
}
return GOPATH
}
// GetModuleName returns the value of module in `go.mod` file.
func GetModuleName(pathToProjectRoot string) (string, error) {
var moduleName string
loopPath := pathToProjectRoot
for {
if idx := strings.LastIndex(loopPath, string(filepath.Separator)); idx >= 0 {
gomodPath := filepath.Join(loopPath, "go.mod")
gomodBytes, err := ioutil.ReadFile(gomodPath)
if err != nil {
loopPath = loopPath[:idx]
continue
}
gomodContent := string(gomodBytes)
moduleIdx := strings.Index(gomodContent, "module ")
newLineIdx := strings.Index(gomodContent, "\n")
if moduleIdx >= 0 {
if newLineIdx >= 0 {
moduleName = strings.TrimSpace(gomodContent[moduleIdx+6 : newLineIdx])
moduleName = strings.TrimSuffix(moduleName, "\r")
} else {
moduleName = strings.TrimSpace(gomodContent[moduleIdx+6:])
}
return moduleName, nil
}
return "", fmt.Errorf("can not get module path in `%s`", gomodPath)
}
break
}
return moduleName, fmt.Errorf("no `go.mod` file in every parent directory of `%s`", pathToProjectRoot)
}