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package main
// stress test to validate encoding/decoding doesn't crash or have inconsistent
// results due to gc interaction with cgo code. To run:
// go run stress_test/main.go -dir=<directory with JPEG images>
import (
"bytes"
"flag"
"fmt"
"image"
"io/ioutil"
"os"
"os/user"
"path/filepath"
"reflect"
"runtime"
"strings"
"sync"
"sync/atomic"
"github.com/kjk/golibjpegturbo"
"github.com/kr/fs"
)
func panicIfErr(err error) {
if err != nil {
panic(err.Error())
}
}
var (
nEncoded int32
nTotalEncodedSize int64
mu sync.Mutex
)
type ImageInfo struct {
path string
data []byte
img image.Image
encodedData []byte
}
func encodeLibjpeg(img image.Image) []byte {
var buf bytes.Buffer
options := &golibjpegturbo.Options{Quality: 90}
err := golibjpegturbo.Encode(&buf, img, options)
panicIfErr(err)
return buf.Bytes()
}
func pathExists(path string) bool {
_, err := os.Stat(path)
return err == nil
}
func userHomeDir() string {
// user.Current() returns nil if cross-compiled e.g. on mac for linux
if usr, _ := user.Current(); usr != nil {
return usr.HomeDir
}
return os.Getenv("HOME")
}
func expandTildeInPath(s string) string {
if strings.HasPrefix(s, "~") {
return userHomeDir() + s[1:]
}
return s
}
func isJpegFile(path string) bool {
ext := filepath.Ext(path)
ext = strings.ToLower(ext)
return ext == ".jpg" || ext == ".jpeg"
}
func validateImgEq(img1, img2 image.Image) {
same := reflect.DeepEqual(img1, img2)
if !same {
panic("decoded image not consistent across runs")
}
}
func decodeEncodeWorker(c chan *ImageInfo) {
for ii := range c {
d := ii.data
r := bytes.NewReader(d)
img, err := golibjpegturbo.Decode(r)
if err != nil {
// we have decoded the image during setup, so this should always succeed
panic(fmt.Sprintf("failed to decode %s with %s\n", ii.path, err))
}
validateImgEq(ii.img, img)
encoded := encodeLibjpeg(img)
mu.Lock()
if ii.encodedData == nil {
ii.encodedData = encoded
}
mu.Unlock()
if !bytes.Equal(encoded, ii.encodedData) {
panic("encoded data not consistent across runs")
}
atomic.AddInt64(&nTotalEncodedSize, int64(len(encoded)))
n := atomic.AddInt32(&nEncoded, 1)
if n%100 == 0 {
fmt.Printf("Decoded/encoded %d images\n", n)
}
}
}
func main() {
runtime.GOMAXPROCS(runtime.NumCPU())
var flagDir string
flag.StringVar(&flagDir, "dir", "", "directory with images")
flag.Parse()
if flagDir == "" {
flag.Usage()
os.Exit(2)
}
dir := expandTildeInPath(flagDir)
if !pathExists(dir) {
fmt.Printf("dir %s doesn't exist\n", dir)
flag.Usage()
os.Exit(2)
}
walker := fs.Walk(dir)
var imagePaths []string
nMaxImages := 100
for walker.Step() {
st := walker.Stat()
if !st.Mode().IsRegular() {
continue
}
path := walker.Path()
if !isJpegFile(path) {
continue
}
imagePaths = append(imagePaths, path)
if len(imagePaths) >= nMaxImages {
break
}
}
if len(imagePaths) == 0 {
fmt.Printf("There are no jpeg images in %s\n", dir)
flag.Usage()
os.Exit(2)
}
var images []*ImageInfo
for _, path := range imagePaths {
data, err := ioutil.ReadFile(path)
if err != nil {
fmt.Printf("ioutil.ReadFile() failed with %s\n", err)
continue
}
img, err := golibjpegturbo.DecodeData(data)
if err != nil {
fmt.Printf("Failed to decode %s with %s\n", path, err)
continue
}
ii := &ImageInfo{
path: path,
data: data,
img: img,
}
images = append(images, ii)
}
fmt.Printf("Read %d images\n", len(images))
c := make(chan *ImageInfo)
nWorkers := runtime.NumCPU() - 2 // don't fully overload the machine
if nWorkers < 1 {
nWorkers = 1
}
fmt.Printf("Staring %d workers\n", nWorkers)
for i := 0; i < nWorkers; i++ {
go decodeEncodeWorker(c)
}
fmt.Printf("To stop me, use Ctrl-C. Otherwise, I'll just keep going\n")
i := 0
for {
c <- images[i]
i++
i = i % len(images)
}
}
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