add embed tool

util/embed/main.go

@@ -0,0 +1,157 @@
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+	"text/template"
+)
+
+var funcs = map[string]interface{}{
+	"formatBytes": formatBytes,
+}
+
+var (
+	tmpl = template.Must(template.New("").Funcs(funcs).Parse(`// +build web
+
+// code is generated by embed. DO NOT EDIT.
+package {{ .Package }}
+
+import (
+	"bytes"
+	"errors"
+	"net/http"
+	"os"
+	"time"
+)
+
+var assets = map[string][]byte{}
+
+var FS = &fs{}
+
+type fs struct {}
+
+func (fs *fs) Open(name string) (http.File, error) {
+	if name == "/" {
+		return fs, nil;
+	}
+	b, ok := assets[name]
+	if !ok {
+		return nil, os.ErrNotExist
+	}
+	return &file{name: name, size: len(b), Reader: bytes.NewReader(b)}, nil
+}
+
+func (fs *fs) Close() error { return nil }
+func (fs *fs) Read(p []byte) (int, error) { return 0, nil }
+func (fs *fs) Seek(offset int64, whence int) (int64, error) { return 0, nil }
+func (fs *fs) Stat() (os.FileInfo, error) { return fs, nil }
+func (fs *fs) Name() string { return "/" }
+func (fs *fs) Size() int64 { return 0 }
+func (fs *fs) Mode() os.FileMode { return 0755}
+func (fs *fs) ModTime() time.Time{ return time.Time{} }
+func (fs *fs) IsDir() bool { return true }
+func (fs *fs) Sys() interface{} { return nil }
+func (fs *fs) Readdir(count int) ([]os.FileInfo, error) {
+	files := []os.FileInfo{}
+	for name, data := range assets {
+		files = append(files, &file{name: name, size: len(data), Reader: bytes.NewReader(data)})
+	}
+	return files, nil
+}
+
+type file struct {
+	name string
+	size int
+	*bytes.Reader 
+}
+
+func (f *file) Close() error { return nil }
+func (f *file) Readdir(count int) ([]os.FileInfo, error) { return nil, errors.New("readdir is not supported") }
+func (f *file) Stat() (os.FileInfo, error) { return f, nil }
+func (f *file) Name() string { return f.name }
+func (f *file) Size() int64 { return int64(f.size) }
+func (f *file) Mode() os.FileMode { return 0644 }
+func (f *file) ModTime() time.Time{ return time.Time{} }
+func (f *file) IsDir() bool { return false }
+func (f *file) Sys() interface{} { return nil }
+
+`)))
+
+// Embed is a helper function that embeds assets from the given directories
+// into a Go source file. It is designed to be called from some generator
+// script, see example project to find out how it can be used.
+func Embed(packageName, file string, dirs ...string) error {
+	var buf bytes.Buffer
+
+	// Execute template
+	if err := tmpl.Execute(&buf, struct{
+		Package string
+	}{
+		Package: packageName,
+	}); err != nil {
+		return err
+	}
+
+	w, err := os.Create(file)
+	if err != nil {
+		return err
+	}
+
+	defer w.Close()
+
+	fmt.Fprintln(w, buf.String())
+	fmt.Fprintln(w, `func init() {`)
+
+	for _, dir := range dirs {
+		filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+			if info.IsDir() {
+				return nil
+			}
+
+			log.Printf("packing %s...", path)
+
+			b, err := ioutil.ReadFile(path)
+			if err != nil {
+				return err
+			}
+
+			path = filepath.ToSlash(path)
+			fmt.Fprintf(w, `	assets[%q] = []byte{`, strings.TrimPrefix(path, dir))
+			fmt.Fprintf(w, formatBytes(b))
+			fmt.Fprintln(w, `}`)
+			return nil
+		})
+	}
+
+	fmt.Fprintln(w, `}`)
+
+	return nil
+}
+
+func formatBytes(s []byte) string {
+	var builder strings.Builder
+	for _, v := range s {
+		builder.WriteString(fmt.Sprintf("0x%02x, ", int(v)))
+	}
+	return builder.String()
+}
+
+
+func main() {
+	var packageName string
+	var outputFile string
+
+	flag.StringVar(&packageName,"package", "", "package name")
+	flag.StringVar(&outputFile,"output", "assets.go", "output filename")
+	flag.Parse()
+	args := flag.Args()
+	if err := Embed(packageName, outputFile, args...) ; err != nil {
+		log.Fatal(err)
+	}
+}