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// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
package version
import (
"strings"
)
// AtLeast returns whether version is at least the specified minimum
// version.
//
// Version comparison in Tailscale is a little complex, because we
// switched "styles" a few times, and additionally have a completely
// separate track of version numbers for OSS-only builds.
//
// AtLeast acts conservatively, returning true only if it's certain
// that version is at least minimum. As a result, it can produce false
// negatives, for example when an OSS build supports a given feature,
// but AtLeast is called with an official release number as the
// minimum
//
// version and minimum can both be either an official Tailscale
// version numbers (major.minor.patch-extracommits-extrastring), or an
// OSS build datestamp (date.YYYYMMDD). For Tailscale version numbers,
// AtLeast also accepts a prefix of a full version, in which case all
// missing fields are assumed to be zero.
func AtLeast(version string, minimum string) bool {
v, ok := parse(version)
if !ok {
return false
}
m, ok := parse(minimum)
if !ok {
return false
}
switch {
case v.Datestamp != 0 && m.Datestamp == 0:
// OSS version vs. Tailscale version
return false
case v.Datestamp == 0 && m.Datestamp != 0:
// Tailscale version vs. OSS version
return false
case v.Datestamp != 0:
// OSS version vs. OSS version
return v.Datestamp >= m.Datestamp
case v.Major == m.Major && v.Minor == m.Minor && v.Patch == m.Patch && v.ExtraCommits == m.ExtraCommits:
// Exactly equal Tailscale versions
return true
case v.Major != m.Major:
return v.Major > m.Major
case v.Minor != m.Minor:
return v.Minor > m.Minor
case v.Patch != m.Patch:
return v.Patch > m.Patch
default:
return v.ExtraCommits > m.ExtraCommits
}
}
type parsed struct {
Major, Minor, Patch, ExtraCommits int // for Tailscale version e.g. e.g. "0.99.1-20"
Datestamp int // for OSS version e.g. "date.20200612"
}
func parse(version string) (parsed, bool) {
if strings.HasPrefix(version, "date.") {
stamp, ok := atoi(version[5:])
if !ok {
return parsed{}, false
}
return parsed{Datestamp: stamp}, true
}
var ret parsed
major, rest, ok := splitNumericPrefix(version)
if !ok {
return parsed{}, false
}
ret.Major = major
if len(rest) == 0 {
return ret, true
}
ret.Minor, rest, ok = splitNumericPrefix(rest[1:])
if !ok {
return parsed{}, false
}
if len(rest) == 0 {
return ret, true
}
// Optional patch version, if the next separator is a dot.
if rest[0] == '.' {
ret.Patch, rest, ok = splitNumericPrefix(rest[1:])
if !ok {
return parsed{}, false
}
if len(rest) == 0 {
return ret, true
}
}
// Ignore trailer like '_1 (Void Linux)'.
if rest[0] == '_' && strings.HasSuffix(rest, " (Void Linux)") {
return ret, true
}
// Optional extraCommits, if the next bit can be completely
// consumed as an integer.
if rest[0] != '-' {
return parsed{}, false
}
var trailer string
ret.ExtraCommits, trailer, ok = splitNumericPrefix(rest[1:])
if !ok || (len(trailer) > 0 && trailer[0] != '-') {
// rest was probably the string trailer, ignore it.
ret.ExtraCommits = 0
}
return ret, true
}
func splitNumericPrefix(s string) (n int, rest string, ok bool) {
for i, r := range s {
if r >= '0' && r <= '9' {
continue
}
ret, ok := atoi(s[:i])
if !ok {
return 0, "", false
}
return ret, s[i:], true
}
ret, ok := atoi(s)
if !ok {
return 0, "", false
}
return ret, "", true
}
const (
maxUint = ^uint(0)
maxInt = int(maxUint >> 1)
)
// atoi parses an int from a string s.
// The bool result reports whether s is a number
// representable by a value of type int.
//
// From Go's runtime/string.go.
func atoi(s string) (int, bool) {
if s == "" {
return 0, false
}
neg := false
if s[0] == '-' {
neg = true
s = s[1:]
}
un := uint(0)
for i := range len(s) {
c := s[i]
if c < '0' || c > '9' {
return 0, false
}
if un > maxUint/10 {
// overflow
return 0, false
}
un *= 10
un1 := un + uint(c) - '0'
if un1 < un {
// overflow
return 0, false
}
un = un1
}
if !neg && un > uint(maxInt) {
return 0, false
}
if neg && un > uint(maxInt)+1 {
return 0, false
}
n := int(un)
if neg {
n = -n
}
return n, true
}
|
