gtsocial-umbx

semver.go (9058B)

---

 // Copyright 2018 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 semver implements comparison of semantic version strings.
 // In this package, semantic version strings must begin with a leading "v",
 // as in "v1.0.0".
 //
 // The general form of a semantic version string accepted by this package is
 //
 //	vMAJOR[.MINOR[.PATCH[-PRERELEASE][+BUILD]]]
 //
 // where square brackets indicate optional parts of the syntax;
 // MAJOR, MINOR, and PATCH are decimal integers without extra leading zeros;
 // PRERELEASE and BUILD are each a series of non-empty dot-separated identifiers
 // using only alphanumeric characters and hyphens; and
 // all-numeric PRERELEASE identifiers must not have leading zeros.
 //
 // This package follows Semantic Versioning 2.0.0 (see semver.org)
 // with two exceptions. First, it requires the "v" prefix. Second, it recognizes
 // vMAJOR and vMAJOR.MINOR (with no prerelease or build suffixes)
 // as shorthands for vMAJOR.0.0 and vMAJOR.MINOR.0.
 package semver
 
 import "sort"
 
 // parsed returns the parsed form of a semantic version string.
 type parsed struct {
 	major      string
 	minor      string
 	patch      string
 	short      string
 	prerelease string
 	build      string
 }
 
 // IsValid reports whether v is a valid semantic version string.
 func IsValid(v string) bool {
 	_, ok := parse(v)
 	return ok
 }
 
 // Canonical returns the canonical formatting of the semantic version v.
 // It fills in any missing .MINOR or .PATCH and discards build metadata.
 // Two semantic versions compare equal only if their canonical formattings
 // are identical strings.
 // The canonical invalid semantic version is the empty string.
 func Canonical(v string) string {
 	p, ok := parse(v)
 	if !ok {
 		return ""
 	}
 	if p.build != "" {
 		return v[:len(v)-len(p.build)]
 	}
 	if p.short != "" {
 		return v + p.short
 	}
 	return v
 }
 
 // Major returns the major version prefix of the semantic version v.
 // For example, Major("v2.1.0") == "v2".
 // If v is an invalid semantic version string, Major returns the empty string.
 func Major(v string) string {
 	pv, ok := parse(v)
 	if !ok {
 		return ""
 	}
 	return v[:1+len(pv.major)]
 }
 
 // MajorMinor returns the major.minor version prefix of the semantic version v.
 // For example, MajorMinor("v2.1.0") == "v2.1".
 // If v is an invalid semantic version string, MajorMinor returns the empty string.
 func MajorMinor(v string) string {
 	pv, ok := parse(v)
 	if !ok {
 		return ""
 	}
 	i := 1 + len(pv.major)
 	if j := i + 1 + len(pv.minor); j <= len(v) && v[i] == '.' && v[i+1:j] == pv.minor {
 		return v[:j]
 	}
 	return v[:i] + "." + pv.minor
 }
 
 // Prerelease returns the prerelease suffix of the semantic version v.
 // For example, Prerelease("v2.1.0-pre+meta") == "-pre".
 // If v is an invalid semantic version string, Prerelease returns the empty string.
 func Prerelease(v string) string {
 	pv, ok := parse(v)
 	if !ok {
 		return ""
 	}
 	return pv.prerelease
 }
 
 // Build returns the build suffix of the semantic version v.
 // For example, Build("v2.1.0+meta") == "+meta".
 // If v is an invalid semantic version string, Build returns the empty string.
 func Build(v string) string {
 	pv, ok := parse(v)
 	if !ok {
 		return ""
 	}
 	return pv.build
 }
 
 // Compare returns an integer comparing two versions according to
 // semantic version precedence.
 // The result will be 0 if v == w, -1 if v < w, or +1 if v > w.
 //
 // An invalid semantic version string is considered less than a valid one.
 // All invalid semantic version strings compare equal to each other.
 func Compare(v, w string) int {
 	pv, ok1 := parse(v)
 	pw, ok2 := parse(w)
 	if !ok1 && !ok2 {
 		return 0
 	}
 	if !ok1 {
 		return -1
 	}
 	if !ok2 {
 		return +1
 	}
 	if c := compareInt(pv.major, pw.major); c != 0 {
 		return c
 	}
 	if c := compareInt(pv.minor, pw.minor); c != 0 {
 		return c
 	}
 	if c := compareInt(pv.patch, pw.patch); c != 0 {
 		return c
 	}
 	return comparePrerelease(pv.prerelease, pw.prerelease)
 }
 
 // Max canonicalizes its arguments and then returns the version string
 // that compares greater.
 //
 // Deprecated: use Compare instead. In most cases, returning a canonicalized
 // version is not expected or desired.
 func Max(v, w string) string {
 	v = Canonical(v)
 	w = Canonical(w)
 	if Compare(v, w) > 0 {
 		return v
 	}
 	return w
 }
 
 // ByVersion implements sort.Interface for sorting semantic version strings.
 type ByVersion []string
 
 func (vs ByVersion) Len() int      { return len(vs) }
 func (vs ByVersion) Swap(i, j int) { vs[i], vs[j] = vs[j], vs[i] }
 func (vs ByVersion) Less(i, j int) bool {
 	cmp := Compare(vs[i], vs[j])
 	if cmp != 0 {
 		return cmp < 0
 	}
 	return vs[i] < vs[j]
 }
 
 // Sort sorts a list of semantic version strings using ByVersion.
 func Sort(list []string) {
 	sort.Sort(ByVersion(list))
 }
 
 func parse(v string) (p parsed, ok bool) {
 	if v == "" || v[0] != 'v' {
 		return
 	}
 	p.major, v, ok = parseInt(v[1:])
 	if !ok {
 		return
 	}
 	if v == "" {
 		p.minor = "0"
 		p.patch = "0"
 		p.short = ".0.0"
 		return
 	}
 	if v[0] != '.' {
 		ok = false
 		return
 	}
 	p.minor, v, ok = parseInt(v[1:])
 	if !ok {
 		return
 	}
 	if v == "" {
 		p.patch = "0"
 		p.short = ".0"
 		return
 	}
 	if v[0] != '.' {
 		ok = false
 		return
 	}
 	p.patch, v, ok = parseInt(v[1:])
 	if !ok {
 		return
 	}
 	if len(v) > 0 && v[0] == '-' {
 		p.prerelease, v, ok = parsePrerelease(v)
 		if !ok {
 			return
 		}
 	}
 	if len(v) > 0 && v[0] == '+' {
 		p.build, v, ok = parseBuild(v)
 		if !ok {
 			return
 		}
 	}
 	if v != "" {
 		ok = false
 		return
 	}
 	ok = true
 	return
 }
 
 func parseInt(v string) (t, rest string, ok bool) {
 	if v == "" {
 		return
 	}
 	if v[0] < '0' || '9' < v[0] {
 		return
 	}
 	i := 1
 	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
 		i++
 	}
 	if v[0] == '0' && i != 1 {
 		return
 	}
 	return v[:i], v[i:], true
 }
 
 func parsePrerelease(v string) (t, rest string, ok bool) {
 	// "A pre-release version MAY be denoted by appending a hyphen and
 	// a series of dot separated identifiers immediately following the patch version.
 	// Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-].
 	// Identifiers MUST NOT be empty. Numeric identifiers MUST NOT include leading zeroes."
 	if v == "" || v[0] != '-' {
 		return
 	}
 	i := 1
 	start := 1
 	for i < len(v) && v[i] != '+' {
 		if !isIdentChar(v[i]) && v[i] != '.' {
 			return
 		}
 		if v[i] == '.' {
 			if start == i || isBadNum(v[start:i]) {
 				return
 			}
 			start = i + 1
 		}
 		i++
 	}
 	if start == i || isBadNum(v[start:i]) {
 		return
 	}
 	return v[:i], v[i:], true
 }
 
 func parseBuild(v string) (t, rest string, ok bool) {
 	if v == "" || v[0] != '+' {
 		return
 	}
 	i := 1
 	start := 1
 	for i < len(v) {
 		if !isIdentChar(v[i]) && v[i] != '.' {
 			return
 		}
 		if v[i] == '.' {
 			if start == i {
 				return
 			}
 			start = i + 1
 		}
 		i++
 	}
 	if start == i {
 		return
 	}
 	return v[:i], v[i:], true
 }
 
 func isIdentChar(c byte) bool {
 	return 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' || '0' <= c && c <= '9' || c == '-'
 }
 
 func isBadNum(v string) bool {
 	i := 0
 	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
 		i++
 	}
 	return i == len(v) && i > 1 && v[0] == '0'
 }
 
 func isNum(v string) bool {
 	i := 0
 	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
 		i++
 	}
 	return i == len(v)
 }
 
 func compareInt(x, y string) int {
 	if x == y {
 		return 0
 	}
 	if len(x) < len(y) {
 		return -1
 	}
 	if len(x) > len(y) {
 		return +1
 	}
 	if x < y {
 		return -1
 	} else {
 		return +1
 	}
 }
 
 func comparePrerelease(x, y string) int {
 	// "When major, minor, and patch are equal, a pre-release version has
 	// lower precedence than a normal version.
 	// Example: 1.0.0-alpha < 1.0.0.
 	// Precedence for two pre-release versions with the same major, minor,
 	// and patch version MUST be determined by comparing each dot separated
 	// identifier from left to right until a difference is found as follows:
 	// identifiers consisting of only digits are compared numerically and
 	// identifiers with letters or hyphens are compared lexically in ASCII
 	// sort order. Numeric identifiers always have lower precedence than
 	// non-numeric identifiers. A larger set of pre-release fields has a
 	// higher precedence than a smaller set, if all of the preceding
 	// identifiers are equal.
 	// Example: 1.0.0-alpha < 1.0.0-alpha.1 < 1.0.0-alpha.beta <
 	// 1.0.0-beta < 1.0.0-beta.2 < 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0."
 	if x == y {
 		return 0
 	}
 	if x == "" {
 		return +1
 	}
 	if y == "" {
 		return -1
 	}
 	for x != "" && y != "" {
 		x = x[1:] // skip - or .
 		y = y[1:] // skip - or .
 		var dx, dy string
 		dx, x = nextIdent(x)
 		dy, y = nextIdent(y)
 		if dx != dy {
 			ix := isNum(dx)
 			iy := isNum(dy)
 			if ix != iy {
 				if ix {
 					return -1
 				} else {
 					return +1
 				}
 			}
 			if ix {
 				if len(dx) < len(dy) {
 					return -1
 				}
 				if len(dx) > len(dy) {
 					return +1
 				}
 			}
 			if dx < dy {
 				return -1
 			} else {
 				return +1
 			}
 		}
 	}
 	if x == "" {
 		return -1
 	} else {
 		return +1
 	}
 }
 
 func nextIdent(x string) (dx, rest string) {
 	i := 0
 	for i < len(x) && x[i] != '.' {
 		i++
 	}
 	return x[:i], x[i:]
 }