oauth2/google/internal/externalaccount/header.go

65 lines
1.6 KiB
Go

// Copyright 2023 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 externalaccount
import (
"runtime"
"strings"
"unicode"
)
var (
// version is a package internal global variable for testing purposes.
version = runtime.Version
)
// versionUnknown is only used when the runtime version cannot be determined.
const versionUnknown = "UNKNOWN"
// goVersion returns a Go runtime version derived from the runtime environment
// that is modified to be suitable for reporting in a header, meaning it has no
// whitespace. If it is unable to determine the Go runtime version, it returns
// versionUnknown.
func goVersion() string {
const develPrefix = "devel +"
s := version()
if strings.HasPrefix(s, develPrefix) {
s = s[len(develPrefix):]
if p := strings.IndexFunc(s, unicode.IsSpace); p >= 0 {
s = s[:p]
}
return s
} else if p := strings.IndexFunc(s, unicode.IsSpace); p >= 0 {
s = s[:p]
}
notSemverRune := func(r rune) bool {
return !strings.ContainsRune("0123456789.", r)
}
if strings.HasPrefix(s, "go1") {
s = s[2:]
var prerelease string
if p := strings.IndexFunc(s, notSemverRune); p >= 0 {
s, prerelease = s[:p], s[p:]
}
if strings.HasSuffix(s, ".") {
s += "0"
} else if strings.Count(s, ".") < 2 {
s += ".0"
}
if prerelease != "" {
// Some release candidates already have a dash in them.
if !strings.HasPrefix(prerelease, "-") {
prerelease = "-" + prerelease
}
s += prerelease
}
return s
}
return "UNKNOWN"
}