From 56f2e3a4515314aa229e11baf28e9dbbfe9e269a Mon Sep 17 00:00:00 2001
From: Chris Koch <chrisko@google.com>
Date: Wed, 28 Feb 2024 02:10:03 +0000
Subject: [PATCH] Generate template dependency file

Signed-off-by: Chris Koch <chrisko@google.com>
---
 cmd/gentpldeps/.gitignore |   1 +
 cmd/gentpldeps/main.go    | 102 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 103 insertions(+)
 create mode 100644 cmd/gentpldeps/.gitignore
 create mode 100644 cmd/gentpldeps/main.go

diff --git a/cmd/gentpldeps/.gitignore b/cmd/gentpldeps/.gitignore
new file mode 100644
index 0000000..50ca3a9
--- /dev/null
+++ b/cmd/gentpldeps/.gitignore
@@ -0,0 +1 @@
+gentpldeps
diff --git a/cmd/gentpldeps/main.go b/cmd/gentpldeps/main.go
new file mode 100644
index 0000000..d4592bf
--- /dev/null
+++ b/cmd/gentpldeps/main.go
@@ -0,0 +1,102 @@
+// Copyright 2024 the u-root Authors. All rights reserved
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// gentpldeps generates a command dependency Go file.
+//
+// Usage:
+//   - go get $module...
+//   - create .mkuimage.yaml file with commands
+//   - gentpldeps -t <tag> -o deps.go -p <pkg>
+package main
+
+import (
+	"bytes"
+	"flag"
+	"log"
+	"os"
+	"sort"
+	"text/template"
+
+	"github.com/u-root/gobusybox/src/pkg/bb/findpkg"
+	"github.com/u-root/gobusybox/src/pkg/golang"
+	"github.com/u-root/mkuimage/uimage/mkuimage"
+	"golang.org/x/exp/maps"
+)
+
+var (
+	pkg = flag.String("p", "", "Package")
+	o   = flag.String("o", "", "Output file name")
+	tag = flag.String("t", "", "Go build tag for the file")
+)
+
+func main() {
+	tf := &mkuimage.TemplateFlags{}
+	tf.RegisterFlags(flag.CommandLine)
+	flag.Parse()
+
+	if *pkg == "" {
+		log.Fatal("Must specify package name")
+	}
+	if *tag == "" {
+		log.Fatal("Must specify Go build tag")
+	}
+	if *o == "" {
+		log.Fatal("Must specify output file name")
+	}
+
+	tpls, err := tf.Get()
+	if err != nil {
+		log.Fatal(err)
+	}
+	if tpls == nil {
+		log.Fatalf("No template found")
+	}
+
+	var cmds []string
+	for _, c := range tpls.Commands {
+		cmds = append(cmds, c...)
+	}
+	for _, conf := range tpls.Configs {
+		for _, c := range conf.Commands {
+			cmds = append(cmds, tpls.CommandsFor(c.Commands...)...)
+		}
+	}
+	paths, err := findpkg.ResolveGlobs(nil, golang.Default(), findpkg.DefaultEnv(), cmds)
+	if err != nil {
+		log.Fatal(err)
+	}
+	dedup := map[string]struct{}{}
+	for _, p := range paths {
+		dedup[p] = struct{}{}
+	}
+	c := maps.Keys(dedup)
+	sort.Strings(c)
+
+	tpl := `//go:build {{.Tag}}
+
+package {{.Package}}
+
+import ({{range .Imports}}
+	_ "{{.}}"{{end}}
+)
+`
+
+	vars := struct {
+		Tag     string
+		Package string
+		Imports []string
+	}{
+		Tag:     *tag,
+		Package: *pkg,
+		Imports: c,
+	}
+	t := template.Must(template.New("tpl").Parse(tpl))
+	var b bytes.Buffer
+	if err := t.Execute(&b, vars); err != nil {
+		log.Fatal(err)
+	}
+	if err := os.WriteFile(*o, b.Bytes(), 0o644); err != nil {
+		log.Fatal(err)
+	}
+}