72 lines
2.1 KiB
Go
72 lines
2.1 KiB
Go
// Copyright 2022 The Go 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 scan
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import (
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"fmt"
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"strings"
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"golang.org/x/mod/semver"
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)
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// Support functions for standard library packages.
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// These are copied from the internal/stdlib package in the pkgsite repo.
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// semverToGoTag returns the Go standard library repository tag corresponding
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// to semver, a version string without the initial "v".
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// Go tags differ from standard semantic versions in a few ways,
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// such as beginning with "go" instead of "v".
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func semverToGoTag(v string) string {
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if strings.HasPrefix(v, "v0.0.0") {
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return "master"
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}
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// Special case: v1.0.0 => go1.
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if v == "v1.0.0" {
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return "go1"
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}
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if !semver.IsValid(v) {
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return fmt.Sprintf("<!%s:invalid semver>", v)
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}
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goVersion := semver.Canonical(v)
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prerelease := semver.Prerelease(goVersion)
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versionWithoutPrerelease := strings.TrimSuffix(goVersion, prerelease)
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patch := strings.TrimPrefix(versionWithoutPrerelease, semver.MajorMinor(goVersion)+".")
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if patch == "0" {
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versionWithoutPrerelease = strings.TrimSuffix(versionWithoutPrerelease, ".0")
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}
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goVersion = fmt.Sprintf("go%s", strings.TrimPrefix(versionWithoutPrerelease, "v"))
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if prerelease != "" {
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// Go prereleases look like "beta1" instead of "beta.1".
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// "beta1" is bad for sorting (since beta10 comes before beta9), so
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// require the dot form.
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i := finalDigitsIndex(prerelease)
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if i >= 1 {
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if prerelease[i-1] != '.' {
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return fmt.Sprintf("<!%s:final digits in a prerelease must follow a period>", v)
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}
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// Remove the dot.
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prerelease = prerelease[:i-1] + prerelease[i:]
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}
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goVersion += strings.TrimPrefix(prerelease, "-")
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}
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return goVersion
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}
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// finalDigitsIndex returns the index of the first digit in the sequence of digits ending s.
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// If s doesn't end in digits, it returns -1.
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func finalDigitsIndex(s string) int {
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// Assume ASCII (since the semver package does anyway).
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var i int
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for i = len(s) - 1; i >= 0; i-- {
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if s[i] < '0' || s[i] > '9' {
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break
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}
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}
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if i == len(s)-1 {
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return -1
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}
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return i + 1
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}
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