[go-nuts] throw: all goroutines are asleep - deadlock!

I cannot find the problem. Please help, thanks.


package main

import (
     "fmt"
     "image"
     "log"
     "os"
     "path/filepath"
     "runtime"
     "strings"
)

var workers = runtime.NumCPU()

type tagInfo struct {
     height int
     width int
     name string
}

func main() {
     if len(os.Args) == 1 {
         log.Fatal("Usage: %s <imagename1 [imagename2] ...>",
filepath.Base(os.Args[0]))
     }

     for _, str := range os.Args[1:] {
         ext := strings.ToLower(filepath.Ext(str))

         if ext != ".png" && ext != ".jpg" && ext != ".jpeg" {
             log.Fatal("Usage: %s <imagename1 [imagename2] ...>",
filepath.Base(os.Args[0]))
         }
     }

     images := make(chan string, workers*4)
     results := make(chan tagInfo, 4)

     procressImgTag(images, results, os.Args[1:])
     showResult(results, len(os.Args[1:]))
}

func procressImgTag(img chan string, result chan tagInfo, imgname []string)
{
     for i := 0; i != workers; i++ {
         go doJob(img, result)
     }

     for _, str := range imgname {
         img <- str
     }
     close(img)
}

func doJob(img <-chan string, result chan<- tagInfo) {

     for filename := range img {
         if info, err := os.Stat(filename); err != nil ||
             (info.Mode()&os.ModeType == 1) {
             log.Print("Failed to check file ", filename, ". Error is ", err)
             return
         }
         file, err := os.Open(filename)
         if err != nil {
             log.Print("Failed to open file ", filename, ". Error is ", err)
             return
         }
         defer file.Close()
         config, _, err := image.DecodeConfig(file)
         if err != nil {
             log.Print("Failed to decode file ", filename, ". Error is ",
err)
             return
         }

         result <- tagInfo{width: config.Width, height: config.Height, name:
filename}
     }
}

func showResult(result chan tagInfo, total int) {
     for i := 0; i != total; i++ {
         rlt := <-result
         fmt.Println(rlt)
     }
}