| // Copyright 2023 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. |
| |
| //go:build !go1.22 |
| // +build !go1.22 |
| |
| package versions |
| |
| // Lang returns the Go language version for version x. |
| // If x is not a valid version, Lang returns the empty string. |
| // For example: |
| // |
| // Lang("go1.21rc2") = "go1.21" |
| // Lang("go1.21.2") = "go1.21" |
| // Lang("go1.21") = "go1.21" |
| // Lang("go1") = "go1" |
| // Lang("bad") = "" |
| // Lang("1.21") = "" |
| func Lang(x string) string { |
| v := lang(stripGo(x)) |
| if v == "" { |
| return "" |
| } |
| return x[:2+len(v)] // "go"+v without allocation |
| } |
| |
| // Compare returns -1, 0, or +1 depending on whether |
| // x < y, x == y, or x > y, interpreted as Go versions. |
| // The versions x and y must begin with a "go" prefix: "go1.21" not "1.21". |
| // Invalid versions, including the empty string, compare less than |
| // valid versions and equal to each other. |
| // The language version "go1.21" compares less than the |
| // release candidate and eventual releases "go1.21rc1" and "go1.21.0". |
| // Custom toolchain suffixes are ignored during comparison: |
| // "go1.21.0" and "go1.21.0-bigcorp" are equal. |
| func Compare(x, y string) int { return compare(stripGo(x), stripGo(y)) } |
| |
| // IsValid reports whether the version x is valid. |
| func IsValid(x string) bool { return isValid(stripGo(x)) } |
| |
| // stripGo converts from a "go1.21" version to a "1.21" version. |
| // If v does not start with "go", stripGo returns the empty string (a known invalid version). |
| func stripGo(v string) string { |
| if len(v) < 2 || v[:2] != "go" { |
| return "" |
| } |
| return v[2:] |
| } |
