//go:build ignore
package main
import (
“fmt”
“html/template”
“io”
“log”
“os”
“regexp”
“sort”
“strconv”
“strings”
“time”
git "github.com/go-git/go-git/v5"
"github.com/go-git/go-git/v5/plumbing"
)
const (
busyboxGit = “git://busybox.net/busybox.git”
)
var (
semverDashRegex = regexp.MustCompile(^v?(\d+[\._]\d+[\._]\d+)$)
appletLineRegex = regexp.MustCompile(^//applet:(.*)APPLET(_\w+)?\(\s*([^\s]+)\s*,\s*(\w+\s*,)?\s*BB_DIR_(\w+),)
cFilesRegex = regexp.MustCompile(\.c$)
)
var versionsTemplate = template.Must(template.New(“versions”).Parse(`// Code generated by go generate; DO NOT EDIT.
// This file was generated by go:generate at
// {{ .Timestamp }}
//
// DO NOT EDIT!
//
// To regenerate, run
//
// go generate
//
package {{ .Package }}
func init() {
busyboxLinks = map[string][]string{
{{- range $version, $applets := .Applets }}
“{{$version}}”: {
{{- range $applet := $applets }}
“{{$applet}}”,
{{- end }}
},
{{- end }}
}
busyboxLinks[“default”] = busyboxLinks[“{{ .Default }}”]
}
`))
func main() {
if len(os.Args) < 4 {
log.Fatalf(“usage: %s ”, os.Args[0])
}
targetPackage := os.Args[1]
baseVersion := os.Args[2]
outfile := os.Args[3]
var w io.Writer
if outfile == “-” {
w = os.Stdout
} else {
f, err := os.Create(outfile)
if err != nil {
log.Fatalf(“error: %v”, err)
}
defer f.Close()
w = f
}
applets, err := getBusyboxApplets(baseVersion)
if err != nil {
log.Fatalf(“error: %v”, err)
}
var versions []string
for version := range applets {
versions = append(versions, version)
}
versionsTemplate.Execute(w, struct {
Timestamp time.Time
Package string
Applets map[string][]string
Default string
}{
Timestamp: time.Now(),
Package: targetPackage,
Applets: applets,
Default: highestVersion(versions),
})
}
func getBusyboxApplets(baseVersion string) (map[string][]string, error) {
// clone the repository
dir, err := os.MkdirTemp(“”, “clone-example”)
if err != nil {
return nil, err
}
defer os.RemoveAll(dir) // clean up
// Clones the repository into the given dir, just as a normal git clone does
repo, err := git.PlainClone(dir, false, &git.CloneOptions{
URL: busyboxGit,
})
if err != nil {
return nil, err
}
// get the tags
versions, err := getBusyboxVersions(repo, baseVersion)
// get the applets for each version
applets := make(map[string][]string)
for , version := range versions {
cleanVersion := strings.ReplaceAll(version, "", ".")
applets[cleanVersion], err = getBusyboxAppletsForVersion(repo, version)
if err != nil {
return nil, err
}
}
return applets, nil
}
func getBusyboxVersions(repo *git.Repository, minVersion string) (versions []string, err error) {
// now get the tags
tags, err := repo.Tags()
if err != nil {
return nil, err
}
// iterate over the tags
// we only want those that match semver, and are higher than our base version
err = tags.ForEach(func(tag *plumbing.Reference) error {
tagName := tag.Name().Short()
matches := semverDashRegex.FindAllStringSubmatch(tagName, -1)
if len(matches) < 1 || len(matches[0]) < 2 {
return nil
}
// get to proper . over _
version := strings.ReplaceAll(matches[0][1], “_”, “.”)
if semverLess(version, minVersion) {
return nil
}
versions = append(versions, tagName)
return nil
})
return
}
func getBusyboxAppletsForVersion(repo *git.Repository, version string) (applets []string, err error) {
// checkout the tag
tree, err := repo.Worktree()
if err != nil {
return nil, err
}
err = tree.Checkout(&git.CheckoutOptions{
Branch: plumbing.ReferenceName(“refs/tags/” + version),
})
if err != nil {
return nil, err
}
// find the applets
entries, err := tree.Grep(&git.GrepOptions{
Patterns: []*regexp.Regexp{appletLineRegex},
PathSpecs: []*regexp.Regexp{cFilesRegex},
})
if err != nil {
return nil, err
}
for _, entry := range entries {
line := appletLineToFullPath(entry.Content)
if line != "" {
applets = append(applets, line)
}
}
sort.Strings(applets)
return
}
func semverLess(a, b string) bool {
aParts := strings.Split(a, “.”)
bParts := strings.Split(b, “.”)
for i := 0; i < len(aParts) && i < len(bParts); i++ {
aI, _ := strconv.ParseInt(aParts[i], 10, 64)
bI, _ := strconv.ParseInt(bParts[i], 10, 64)
if aI < bI {
return true
}
if aI > bI {
return false
}
}
return false
}
func appletLineToFullPath(appletLine string) string {
// the line should look something like one of these two:
// //applet:IF_(APPLET(name, location, … ))
// //applet:IF_(APPLET_(name, maincall, location, … ))
//
// location will be BB_DIR_
func highestVersion(versions []string) string {
highest := “”
for _, version := range versions {
if semverLess(highest, version) {
highest = version
}
}
return highest
}
