mirror of
https://github.com/tailscale/tailscale.git
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141 lines
3.5 KiB
Go
141 lines
3.5 KiB
Go
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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package version
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import (
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"strconv"
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"strings"
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)
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// AtLeast returns whether version is at least the specified minimum
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// version.
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//
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// Version comparison in Tailscale is a little complex, because we
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// switched "styles" a few times, and additionally have a completely
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// separate track of version numbers for OSS-only builds.
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//
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// AtLeast acts conservatively, returning true only if it's certain
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// that version is at least minimum. As a result, it can produce false
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// negatives, for example when an OSS build supports a given feature,
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// but AtLeast is called with an official release number as the
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// minimum
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//
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// version and minimum can both be either an official Tailscale
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// version numbers (major.minor.patch-extracommits-extrastring), or an
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// OSS build datestamp (date.YYYYMMDD). For Tailscale version numbers,
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// AtLeast also accepts a prefix of a full version, in which case all
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// missing fields are assumed to be zero.
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func AtLeast(version string, minimum string) bool {
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v, ok := parse(version)
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if !ok {
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return false
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}
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m, ok := parse(minimum)
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if !ok {
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return false
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}
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switch {
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case v.Datestamp != 0 && m.Datestamp == 0:
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// OSS version vs. Tailscale version
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return false
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case v.Datestamp == 0 && m.Datestamp != 0:
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// Tailscale version vs. OSS version
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return false
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case v.Datestamp != 0:
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// OSS version vs. OSS version
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return v.Datestamp >= m.Datestamp
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case v.Major == m.Major && v.Minor == m.Minor && v.Patch == m.Patch && v.ExtraCommits == m.ExtraCommits:
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// Exactly equal Tailscale versions
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return true
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case v.Major != m.Major:
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return v.Major > m.Major
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case v.Minor != m.Minor:
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return v.Minor > m.Minor
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case v.Patch != m.Patch:
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return v.Patch > m.Patch
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default:
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return v.ExtraCommits > m.ExtraCommits
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}
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}
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type parsed struct {
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Major, Minor, Patch, ExtraCommits int // for Tailscale version e.g. e.g. "0.99.1-20"
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Datestamp int // for OSS version e.g. "date.20200612"
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}
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func parse(version string) (parsed, bool) {
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if strings.HasPrefix(version, "date.") {
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stamp, err := strconv.Atoi(version[5:])
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if err != nil {
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return parsed{}, false
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}
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return parsed{Datestamp: stamp}, true
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}
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var ret parsed
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major, rest, err := splitNumericPrefix(version)
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if err != nil {
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return parsed{}, false
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}
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ret.Major = major
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if len(rest) == 0 {
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return ret, true
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}
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ret.Minor, rest, err = splitNumericPrefix(rest[1:])
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if err != nil {
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return parsed{}, false
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}
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if len(rest) == 0 {
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return ret, true
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}
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// Optional patch version, if the next separator is a dot.
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if rest[0] == '.' {
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ret.Patch, rest, err = splitNumericPrefix(rest[1:])
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if err != nil {
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return parsed{}, false
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}
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if len(rest) == 0 {
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return ret, true
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}
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}
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// Optional extraCommits, if the next bit can be completely
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// consumed as an integer.
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if rest[0] != '-' {
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return parsed{}, false
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}
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var trailer string
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ret.ExtraCommits, trailer, err = splitNumericPrefix(rest[1:])
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if err != nil || (len(trailer) > 0 && trailer[0] != '-') {
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// rest was probably the string trailer, ignore it.
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ret.ExtraCommits = 0
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}
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return ret, true
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}
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func splitNumericPrefix(s string) (int, string, error) {
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for i, r := range s {
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if r >= '0' && r <= '9' {
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continue
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}
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ret, err := strconv.Atoi(s[:i])
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if err != nil {
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return 0, "", err
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}
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return ret, s[i:], nil
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}
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ret, err := strconv.Atoi(s)
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if err != nil {
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return 0, "", err
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}
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return ret, "", nil
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}
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