func getMetaInfo(torrent string) (metaInfo *MetaInfo, err os.Error) {
	var input io.ReadCloser
	if strings.HasPrefix(torrent, "http:") {
		// 6g compiler bug prevents us from writing r, _, err :=
		var r *http.Response
		if r, _, err = http.Get(torrent); err != nil {
			return
		}
		input = r.Body
	} else {
		if input, err = os.Open(torrent, os.O_RDONLY, 0666); err != nil {
			return
		}
	}

	// We need to calcuate the sha1 of the Info map, including every value in the
	// map. The easiest way to do this is to read the data using the Decode
	// API, and then pick through it manually.
	var m interface{}
	m, err = bencode.Decode(input)
	input.Close()
	if err != nil {
		err = os.NewError("Couldn't parse torrent file phase 1: " + err.String())
		return
	}

	topMap, ok := m.(map[string]interface{})
	if !ok {
		err = os.NewError("Couldn't parse torrent file phase 2.")
		return
	}

	infoMap, ok := topMap["info"]
	if !ok {
		err = os.NewError("Couldn't parse torrent file. info")
		return
	}
	var b bytes.Buffer
	if err = bencode.Marshal(&b, infoMap); err != nil {
		return
	}
	hash := sha1.New()
	hash.Write(b.Bytes())

	var m2 MetaInfo
	err = bencode.Unmarshal(&b, &m2.Info)
	if err != nil {
		return
	}

	m2.InfoHash = string(hash.Sum())
	m2.Announce = getString(topMap, "announce")
	m2.CreationDate = getString(topMap, "creation date")
	m2.Comment = getString(topMap, "comment")
	m2.CreatedBy = getString(topMap, "created by")
	m2.Encoding = getString(topMap, "encoding")

	metaInfo = &m2
	return
}
func getTrackerInfo(url string) (tr *TrackerResponse, err os.Error) {
	r, _, err := http.Get(url)
	if err != nil {
		return
	}
	defer r.Body.Close()
	if r.StatusCode >= 400 {
		data, _ := ioutil.ReadAll(r.Body)
		reason := "Bad Request " + string(data)
		log.Println(reason)
		err = os.NewError(reason)
		return
	}
	var tr2 TrackerResponse
	err = bencode.Unmarshal(r.Body, &tr2)
	r.Body.Close()
	if err != nil {
		return
	}
	tr = &tr2
	return
}