122 lines
3.2 KiB
Go
122 lines
3.2 KiB
Go
// Package versioncmp provides functions for comparing version strings.
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//
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// Version strings are dot-separated integers with an optional
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// pre-release suffix. A pre-release suffix is an arbitrary string with a
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// leading dash character. All functions ignore these suffixes, so "1.2" and
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// "1.2-rc" are considered equivalent.
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package versioncmp
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import (
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"strconv"
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"strings"
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)
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const (
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rcString = "-rc"
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ceEdition = "-ce"
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)
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// compare compares two versions of Docker to decipher which came first.
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//
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// compare returns -1 if v1 < v2, 1 if v1 > v2, 0 otherwise.
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func compare(v1, v2 string) int {
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// Replace RC string with "." to make the RC number appear as simply
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// another sub-version.
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v1 = strings.Replace(v1, rcString, ".", -1)
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v2 = strings.Replace(v2, rcString, ".", -1)
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// All releases before the community edition (differentiated by
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// presence of the "ce" string in the version string) are "less than"
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// any community edition release (first occuring in March 2017).
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if strings.Contains(v1, ceEdition) && !strings.Contains(v2, ceEdition) {
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return 1
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}
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if !strings.Contains(v1, ceEdition) && strings.Contains(v2, ceEdition) {
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return -1
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}
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// Without this tag, both are pre-CE versions.
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if !strings.Contains(v1, ceEdition) && !strings.Contains(v2, ceEdition) {
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return compareNumeric(v1, v2)
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}
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return compareCE(v1, v2)
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}
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// compareCE ("Community Edition") will differentiate between versions of
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// Docker that use the versioning scheme
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// {{release-year}}.{{release-month}}-{{ce|ee}}-{{rcnum|""}}
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//
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// This will be every release after 1.13.1.
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func compareCE(v1, v2 string) int {
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return compareNumeric(
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strings.Replace(v1, ceEdition, "", -1),
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strings.Replace(v2, ceEdition, "", -1),
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)
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}
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// compareNumeric compares two version that use pre-17.03 Docker.
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//
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// Non-numeric segments in either argument are considered equal, so
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// compare("1.a", "1.b") == 0, but compare("2.a", "1.b") == 1.
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func compareNumeric(v1, v2 string) int {
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if n := strings.IndexByte(v1, '-'); n != -1 {
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v1 = v1[:n]
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}
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if n := strings.IndexByte(v2, '-'); n != -1 {
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v2 = v2[:n]
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}
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var (
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currTab = strings.Split(v1, ".")
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otherTab = strings.Split(v2, ".")
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)
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max := len(currTab)
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if len(otherTab) > max {
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max = len(otherTab)
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}
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for i := 0; i < max; i++ {
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var currInt, otherInt int
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if len(currTab) > i {
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currInt, _ = strconv.Atoi(currTab[i])
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}
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if len(otherTab) > i {
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otherInt, _ = strconv.Atoi(otherTab[i])
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}
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if currInt > otherInt {
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return 1
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}
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if otherInt > currInt {
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return -1
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}
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}
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return 0
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}
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// LessThan checks if a version is less than another.
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func LessThan(v, other string) bool {
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return compare(v, other) == -1
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}
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// LessThanOrEqualTo checks if a version is less than or equal to another.
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func LessThanOrEqualTo(v, other string) bool {
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return compare(v, other) <= 0
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}
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// GreaterThan checks if a version is greater than another.
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func GreaterThan(v, other string) bool {
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return compare(v, other) == 1
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}
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// GreaterThanOrEqualTo checks if a version is greater than or equal to
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// another.
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func GreaterThanOrEqualTo(v, other string) bool {
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return compare(v, other) >= 0
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}
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// Equal checks if a version is equal to another.
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func Equal(v, other string) bool {
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return compare(v, other) == 0
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}
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