package version
import (
"bytes"
"fmt"
"reflect"
"regexp"
"strconv"
"strings"
)
// The compiled regular expression used to test the validity of a version.
var versionRegexp *regexp.Regexp
// The raw regular expression string used for testing the validity
// of a version.
const VersionRegexpRaw string = `v?([0-9]+(\.[0-9]+)*?)` +
`(-?([0-9A-Za-z\-]+(\.[0-9A-Za-z\-]+)*))?` +
`(\+([0-9A-Za-z\-]+(\.[0-9A-Za-z\-]+)*))?` +
`?`
// Version represents a single version.
type Version struct {
metadata string
pre string
segments []int64
si int
}
func init() {
versionRegexp = regexp.MustCompile("^" + VersionRegexpRaw + "$")
}
// NewVersion parses the given version and returns a new
// Version.
func NewVersion(v string) (*Version, error) {
matches := versionRegexp.FindStringSubmatch(v)
if matches == nil {
return nil, fmt.Errorf("Malformed version: %s", v)
}
segmentsStr := strings.Split(matches[1], ".")
segments := make([]int64, len(segmentsStr))
si := 0
for i, str := range segmentsStr {
val, err := strconv.ParseInt(str, 10, 64)
if err != nil {
return nil, fmt.Errorf(
"Error parsing version: %s", err)
}
segments[i] = int64(val)
si++
}
// Even though we could support more than three segments, if we
// got less than three, pad it with 0s. This is to cover the basic
// default usecase of semver, which is MAJOR.MINOR.PATCH at the minimum
for i := len(segments); i < 3; i++ {
segments = append(segments, 0)
}
return &Version{
metadata: matches[7],
pre: matches[4],
segments: segments,
si: si,
}, nil
}
// Must is a helper that wraps a call to a function returning (*Version, error)
// and panics if error is non-nil.
func Must(v *Version, err error) *Version {
if err != nil {
panic(err)
}
return v
}
// Compare compares this version to another version. This
// returns -1, 0, or 1 if this version is smaller, equal,
// or larger than the other version, respectively.
//
// If you want boolean results, use the LessThan, Equal,
// or GreaterThan methods.
func (v *Version) Compare(other *Version) int {
// A quick, efficient equality check
if v.String() == other.String() {
return 0
}
segmentsSelf := v.Segments64()
segmentsOther := other.Segments64()
// If the segments are the same, we must compare on prerelease info
if reflect.DeepEqual(segmentsSelf, segmentsOther) {
preSelf := v.Prerelease()
preOther := other.Prerelease()
if preSelf == "" && preOther == "" {
return 0
}
if preSelf == "" {
return 1
}
if preOther == "" {
return -1
}
return comparePrereleases(preSelf, preOther)
}
// Get the highest specificity (hS), or if they're equal, just use segmentSelf length
lenSelf := len(segmentsSelf)
lenOther := len(segmentsOther)
hS := lenSelf
if lenSelf < lenOther {
hS = lenOther
}
// Compare the segments
// Because a constraint could have more/less specificity than the version it's
// checking, we need to account for a lopsided or jagged comparison
for i := 0; i < hS; i++ {
if i > lenSelf-1 {
// This means Self had the lower specificity
// Check to see if the remaining segments in Other are all zeros
if !allZero(segmentsOther[i:]) {
// if not, it means that Other has to be greater than Self
return -1
}
break
} else if i > lenOther-1 {
// this means Other had the lower specificity
// Check to see if the remaining segments in Self are all zeros -
if !allZero(segmentsSelf[i:]) {
//if not, it means that Self has to be greater than Other
return 1
}
break
}
lhs := segmentsSelf[i]
rhs := segmentsOther[i]
if lhs == rhs {
continue
} else if lhs < rhs {
return -1
}
// Otherwis, rhs was > lhs, they're not equal
return 1
}
// if we got this far, they're equal
return 0
}
func allZero(segs []int64) bool {
for _, s := range segs {
if s != 0 {
return false
}
}
return true
}
func comparePart(preSelf string, preOther string) int {
if preSelf == preOther {
return 0
}
// if a part is empty, we use the other to decide
if preSelf == "" {
_, notIsNumeric := strconv.ParseInt(preOther, 10, 64)
if notIsNumeric == nil {
return -1
}
return 1
}
if preOther == "" {
_, notIsNumeric := strconv.ParseInt(preSelf, 10, 64)
if notIsNumeric == nil {
return 1
}
return -1
}
if preSelf > preOther {
return 1
}
return -1
}
func comparePrereleases(v string, other string) int {
// the same pre release!
if v == other {
return 0
}
// split both pre releases for analyse their parts
selfPreReleaseMeta := strings.Split(v, ".")
otherPreReleaseMeta := strings.Split(other, ".")
selfPreReleaseLen := len(selfPreReleaseMeta)
otherPreReleaseLen := len(otherPreReleaseMeta)
biggestLen := otherPreReleaseLen
if selfPreReleaseLen > otherPreReleaseLen {
biggestLen = selfPreReleaseLen
}
// loop for parts to find the first difference
for i := 0; i < biggestLen; i = i + 1 {
partSelfPre := ""
if i < selfPreReleaseLen {
partSelfPre = selfPreReleaseMeta[i]
}
partOtherPre := ""
if i < otherPreReleaseLen {
partOtherPre = otherPreReleaseMeta[i]
}
compare := comparePart(partSelfPre, partOtherPre)
// if parts are equals, continue the loop
if compare != 0 {
return compare
}
}
return 0
}
// Equal tests if two versions are equal.
func (v *Version) Equal(o *Version) bool {
return v.Compare(o) == 0
}
// GreaterThan tests if this version is greater than another version.
func (v *Version) GreaterThan(o *Version) bool {
return v.Compare(o) > 0
}
// LessThan tests if this version is less than another version.
func (v *Version) LessThan(o *Version) bool {
return v.Compare(o) < 0
}
// Metadata returns any metadata that was part of the version
// string.
//
// Metadata is anything that comes after the "+" in the version.
// For example, with "1.2.3+beta", the metadata is "beta".
func (v *Version) Metadata() string {
return v.metadata
}
// Prerelease returns any prerelease data that is part of the version,
// or blank if there is no prerelease data.
//
// Prerelease information is anything that comes after the "-" in the
// version (but before any metadata). For example, with "1.2.3-beta",
// the prerelease information is "beta".
func (v *Version) Prerelease() string {
return v.pre
}
// Segments returns the numeric segments of the version as a slice of ints.
//
// This excludes any metadata or pre-release information. For example,
// for a version "1.2.3-beta", segments will return a slice of
// 1, 2, 3.
func (v *Version) Segments() []int {
segmentSlice := make([]int, len(v.segments))
for i, v := range v.segments {
segmentSlice[i] = int(v)
}
return segmentSlice
}
// Segments64 returns the numeric segments of the version as a slice of int64s.
//
// This excludes any metadata or pre-release information. For example,
// for a version "1.2.3-beta", segments will return a slice of
// 1, 2, 3.
func (v *Version) Segments64() []int64 {
return v.segments
}
// String returns the full version string included pre-release
// and metadata information.
func (v *Version) String() string {
var buf bytes.Buffer
fmtParts := make([]string, len(v.segments))
for i, s := range v.segments {
// We can ignore err here since we've pre-parsed the values in segments
str := strconv.FormatInt(s, 10)
fmtParts[i] = str
}
fmt.Fprintf(&buf, strings.Join(fmtParts, "."))
if v.pre != "" {
fmt.Fprintf(&buf, "-%s", v.pre)
}
if v.metadata != "" {
fmt.Fprintf(&buf, "+%s", v.metadata)
}
return buf.String()
}
