syncthing/script/genassets.go
greatroar e2febf246e
all: Store assets as strings (#6611)
Storing assets as []byte requires every compiled-in asset to be copied
into writable memory at program startup. That currently takes up 1.6MB
per syncthing process. Strings stay in the RODATA section and should be
shared between processes running the same binary.
2020-05-07 11:47:23 +02:00

122 lines
2.3 KiB
Go

// Copyright (C) 2014 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
// +build ignore
package main
import (
"bytes"
"compress/gzip"
"flag"
"fmt"
"go/format"
"io"
"os"
"path/filepath"
"strconv"
"strings"
"text/template"
"time"
)
var tpl = template.Must(template.New("assets").Parse(`// Code generated by genassets.go - DO NOT EDIT.
package auto
const Generated int64 = {{.Generated}}
func Assets() map[string]string {
var assets = make(map[string]string, {{.Assets | len}})
{{range $asset := .Assets}}
assets["{{$asset.Name}}"] = {{$asset.Data}}{{end}}
return assets
}
`))
type asset struct {
Name string
Data string
}
var assets []asset
func walkerFor(basePath string) filepath.WalkFunc {
return func(name string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if strings.HasPrefix(filepath.Base(name), ".") {
// Skip dotfiles
return nil
}
if info.Mode().IsRegular() {
fd, err := os.Open(name)
if err != nil {
return err
}
var buf bytes.Buffer
gw := gzip.NewWriter(&buf)
io.Copy(gw, fd)
fd.Close()
gw.Flush()
gw.Close()
name, _ = filepath.Rel(basePath, name)
assets = append(assets, asset{
Name: filepath.ToSlash(name),
Data: fmt.Sprintf("%q", buf.String()),
})
}
return nil
}
}
type templateVars struct {
Assets []asset
Generated int64
}
func main() {
outfile := flag.String("o", "", "Name of output file (default stdout)")
flag.Parse()
filepath.Walk(flag.Arg(0), walkerFor(flag.Arg(0)))
var buf bytes.Buffer
// Generated time is now, except if the SOURCE_DATE_EPOCH environment
// variable is set (for reproducible builds).
generated := time.Now().Unix()
if s, _ := strconv.ParseInt(os.Getenv("SOURCE_DATE_EPOCH"), 10, 64); s > 0 {
generated = s
}
tpl.Execute(&buf, templateVars{
Assets: assets,
Generated: generated,
})
bs, err := format.Source(buf.Bytes())
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
out := io.Writer(os.Stdout)
if *outfile != "" {
out, err = os.Create(*outfile)
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
}
out.Write(bs)
}