func sendPSyncFullsync(br *bufio.Reader, bw *bufio.Writer) (string, int64, <-chan int64) {
	cmd := redis.NewCommand("psync", "?", -1)
	if err := redis.Encode(bw, cmd, true); err != nil {
		log.PanicError(err, "write psync command failed, fullsync")
	}
	r, err := redis.Decode(br)
	if err != nil {
		log.PanicError(err, "invalid psync response, fullsync")
	}
	if e, ok := r.(*redis.Error); ok {
		log.Panicf("invalid psync response, fullsync, %s", e.Value)
	}
	x, err := redis.AsString(r, nil)
	if err != nil {
		log.PanicError(err, "invalid psync response, fullsync")
	}
	xx := strings.Split(x, " ")
	if len(xx) != 3 || strings.ToLower(xx[0]) != "fullresync" {
		log.Panicf("invalid psync response = '%s', should be fullsync", x)
	}
	v, err := strconv.ParseInt(xx[2], 10, 64)
	if err != nil {
		log.PanicError(err, "parse psync offset failed")
	}
	runid, offset := xx[1], v-1
	return runid, offset, waitRdbDump(br)
}

func newRDBLoader(reader *bufio.Reader, rbytes *atomic2.Int64, size int) chan *rdb.BinEntry {
	pipe := make(chan *rdb.BinEntry, size)
	go func() {
		defer close(pipe)
		l := rdb.NewLoader(stats.NewCountReader(reader, rbytes))
		if err := l.Header(); err != nil {
			log.PanicError(err, "parse rdb header error")
		}
		for {
			if entry, err := l.NextBinEntry(); err != nil {
				log.PanicError(err, "parse rdb entry error")
			} else {
				if entry != nil {
					pipe <- entry
				} else {
					if err := l.Footer(); err != nil {
						log.PanicError(err, "parse rdb checksum error")
					}
					return
				}
			}
		}
	}()
	return pipe
}

func sendPSyncContinue(br *bufio.Reader, bw *bufio.Writer, runid string, offset int64) {
	cmd := redis.NewCommand("psync", runid, offset+2)
	if err := redis.Encode(bw, cmd, true); err != nil {
		log.PanicError(err, "write psync command failed, continue")
	}
	x, err := redis.AsString(redis.Decode(br))
	if err != nil {
		log.PanicError(err, "invalid psync response, continue")
	}
	xx := strings.Split(x, " ")
	if len(xx) != 1 || strings.ToLower(xx[0]) != "continue" {
		log.Panicf("invalid psync response = '%s', should be continue", x)
	}
}

func MustParse(s string) int64 {
	v, err := Parse(s)
	if err != nil {
		log.PanicError(err, "parse bytesize failed")
	}
	return v
}

func MustDecodeFromBytes(p []byte) Resp {
	resp, err := DecodeFromBytes(p)
	if err != nil {
		log.PanicError(err, "decode redis resp from bytes failed")
	}
	return resp
}

func MustDecode(r *bufio.Reader) Resp {
	resp, err := Decode(r)
	if err != nil {
		log.PanicError(err, "decode redis resp failed")
	}
	return resp
}

func MustHandlerTable(o interface{}) map[string]HandlerFunc {
	t, err := NewHandlerTable(o)
	if err != nil {
		log.PanicError(err, "create redis handler map failed")
	}
	return t
}

func authPassword(c net.Conn, passwd string) {
	if passwd == "" {
		return
	}
	_, err := c.Write(redis.MustEncodeToBytes(redis.NewCommand("auth", passwd)))
	if err != nil {
		log.PanicError(errors.Trace(err), "write auth command failed")
	}
	var b = make([]byte, 5)
	if _, err := io.ReadFull(c, b); err != nil {
		log.PanicError(errors.Trace(err), "read auth response failed")
	}
	if strings.ToUpper(string(b)) != "+OK\r\n" {
		log.Panic("auth failed")
	}
}

func openSyncConn(target string, passwd string) (net.Conn, <-chan int64) {
	c := openNetConn(target, passwd)
	if _, err := c.Write(redis.MustEncodeToBytes(redis.NewCommand("sync"))); err != nil {
		log.PanicError(errors.Trace(err), "write sync command failed")
	}
	return c, waitRdbDump(c)
}

func MustEncodeToBytes(r Resp) []byte {
	b, err := EncodeToBytes(r)
	if err != nil {
		log.PanicError(err, "encode redis resp to bytes failed")
	}
	return b
}

func iocopy(r io.Reader, w io.Writer, p []byte, max int) int {
	if max <= 0 || len(p) == 0 {
		log.Panicf("invalid max = %d, len(p) = %d", max, len(p))
	}
	if len(p) > max {
		p = p[:max]
	}
	if n, err := r.Read(p); err != nil {
		log.PanicError(err, "read error")
	} else {
		p = p[:n]
	}
	if _, err := w.Write(p); err != nil {
		log.PanicError(err, "write error")
	}
	return len(p)
}

func init() {
	const path = "/tmp/testdb2-rocksdb"
	if err := os.RemoveAll(path); err != nil {
		log.PanicErrorf(err, "remove '%s' failed", path)
	} else {
		conf := rocksdb.NewDefaultConfig()
		if testdb, err := rocksdb.Open(path, conf, true, false); err != nil {
			log.PanicError(err, "open rocksdb failed")
		} else {
			testbl2 = rpdb.New(testdb)
		}
	}
	l, err := net.Listen("tcp", ":0")
	if err != nil {
		log.PanicError(err, "open listen port failed")
	}
	port = l.Addr().(*net.TCPAddr).Port
	go func() {
		server := redis.MustServer(&Handler{})
		for {
			c, err := l.Accept()
			if err != nil {
				log.PanicError(err, "accept socket failed")
			}
			go func() {
				defer c.Close()
				r, w := bufio.NewReader(c), bufio.NewWriter(c)
				s := &fakeSession2{}
				for {
					if req, err := redis.Decode(r); err != nil {
						return
					} else {
						if rsp, err := server.Dispatch(s, req); err != nil {
							return
						} else if rsp != nil {
							if err := redis.Encode(w, rsp); err != nil {
								return
							}
						}
					}
				}
			}()
		}
	}()
}

func selectDB(c redigo.Conn, db uint32) {
	s, err := redigo.String(c.Do("select", db))
	if err != nil {
		log.PanicError(err, "select command error")
	}
	if s != "OK" {
		log.Panicf("select command response = '%s', should be 'OK'", s)
	}
}

func (cmd *cmdSync) SyncCommand(reader *bufio.Reader, target, passwd string) {
	c := openNetConn(target, passwd)
	defer c.Close()

	writer := bufio.NewWriterSize(stats.NewCountWriter(c, &cmd.wbytes), WriterBufferSize)
	defer flushWriter(writer)

	go func() {
		p := make([]byte, ReaderBufferSize)
		for {
			iocopy(c, ioutil.Discard, p, len(p))
		}
	}()

	go func() {
		var bypass bool = false
		for {
			resp := redis.MustDecode(reader)
			if scmd, args, err := redis.ParseArgs(resp); err != nil {
				log.PanicError(err, "parse command arguments failed")
			} else if scmd != "ping" {
				if scmd == "select" {
					if len(args) != 1 {
						log.Panicf("select command len(args) = %d", len(args))
					}
					s := string(args[0])
					n, err := parseInt(s, MinDB, MaxDB)
					if err != nil {
						log.PanicErrorf(err, "parse db = %s failed", s)
					}
					bypass = !acceptDB(uint32(n))
				}
				if bypass {
					cmd.nbypass.Incr()
					continue
				}
			}
			cmd.forward.Incr()
			redis.MustEncode(writer, resp)
			flushWriter(writer)
		}
	}()

	for lstat := cmd.Stat(); ; {
		time.Sleep(time.Second)
		nstat := cmd.Stat()
		var b bytes.Buffer
		fmt.Fprintf(&b, "sync: ")
		fmt.Fprintf(&b, " +forward=%-6d", nstat.forward-lstat.forward)
		fmt.Fprintf(&b, " +nbypass=%-6d", nstat.nbypass-lstat.nbypass)
		fmt.Fprintf(&b, " +nbytes=%d", nstat.wbytes-lstat.wbytes)
		log.Info(b.String())
		lstat = nstat
	}
}

func reinit() {
	if testbl != nil {
		testbl.Close()
		testbl = nil
	}
	const path = "/tmp/testdb-rocksdb"
	if err := os.RemoveAll(path); err != nil {
		log.PanicErrorf(err, "remove '%s' failed", path)
	} else {
		conf := rocksdb.NewDefaultConfig()
		if testdb, err := rocksdb.Open(path, conf, true, false); err != nil {
			log.PanicError(err, "open rocksdb failed")
		} else {
			testbl = rpdb.New(testdb)
		}
	}
}

func restoreRdbEntry(c redigo.Conn, e *rdb.BinEntry) {
	var ttlms uint64
	if e.ExpireAt != 0 {
		now := uint64(time.Now().Add(args.shift).UnixNano())
		now /= uint64(time.Millisecond)
		if now >= e.ExpireAt {
			ttlms = 1
		} else {
			ttlms = e.ExpireAt - now
		}
	}
	s, err := redigo.String(c.Do("slotsrestore", e.Key, ttlms, e.Value))
	if err != nil {
		log.PanicError(err, "restore command error")
	}
	if s != "OK" {
		log.Panicf("restore command response = '%s', should be 'OK'", s)
	}
}

func main() {
	usage := `
Usage:
	redis-port decode   [--ncpu=N]  [--parallel=M]  [--input=INPUT]  [--output=OUTPUT]
	redis-port restore  [--ncpu=N]  [--parallel=M]  [--input=INPUT]   --target=TARGET   [--extra]  [--faketime=FAKETIME]  [--filterdb=DB]
	redis-port dump     [--ncpu=N]  [--parallel=M]   --from=MASTER   [--output=OUTPUT]  [--password=PASSWORD]  [--extra]
	redis-port sync     [--ncpu=N]  [--parallel=M]   --from=MASTER    --target=TARGET   [--password=PASSWORD]  [--sockfile=FILE [--filesize=SIZE]] [--filterdb=DB] [--psync]

Options:
	-n N, --ncpu=N                    Set runtime.GOMAXPROCS to N.
	-p M, --parallel=M                Set the number of parallel routines to M.
	-i INPUT, --input=INPUT           Set input file, default is stdin ('/dev/stdin').
	-o OUTPUT, --output=OUTPUT        Set output file, default is stdout ('/dev/stdout').
	-f MASTER, --from=MASTER          Set host:port of master redis.
	-t TARGET, --target=TARGET        Set host:port of slave redis.
	-P PASSWORD, --password=PASSWORD  Set redis auth password.
	--faketime=FAKETIME               Set current system time to adjust key's expire time.
	--sockfile=FILE                   Use FILE to as socket buffer, default is disabled.
	--filesize=SIZE                   Set FILE size, default value is 1gb.
	-e, --extra                       Set ture to send/receive following redis commands, default is false.
	--filterdb=DB                     Filter db = DB, default is *.
	--psync                           Use PSYNC command.
`
	d, err := docopt.Parse(usage, nil, true, "", false)
	if err != nil {
		log.PanicError(err, "parse arguments failed")
	}

	if s, ok := d["--ncpu"].(string); ok && s != "" {
		n, err := parseInt(s, 1, 1024)
		if err != nil {
			log.PanicErrorf(err, "parse --ncpu failed")
		}
		runtime.GOMAXPROCS(n)
	}
	ncpu := runtime.GOMAXPROCS(0)

	if s, ok := d["--parallel"].(string); ok && s != "" {
		n, err := parseInt(s, 1, 1024)
		if err != nil {
			log.PanicErrorf(err, "parse --parallel failed")
		}
		args.parallel = n
	}
	if ncpu > args.parallel {
		args.parallel = ncpu
	}
	if args.parallel == 0 {
		args.parallel = 4
	}

	args.input, _ = d["--input"].(string)
	args.output, _ = d["--output"].(string)

	args.from, _ = d["--from"].(string)
	args.target, _ = d["--target"].(string)
	args.passwd, _ = d["--password"].(string)

	args.extra, _ = d["--extra"].(bool)
	args.psync, _ = d["--psync"].(bool)
	args.sockfile, _ = d["--sockfile"].(string)

	if s, ok := d["--faketime"].(string); ok && s != "" {
		switch s[0] {
		case '-', '+':
			d, err := time.ParseDuration(strings.ToLower(s))
			if err != nil {
				log.PanicError(err, "parse --faketime failed")
			}
			args.shift = d
		case '@':
			n, err := strconv.ParseInt(s[1:], 10, 64)
			if err != nil {
				log.PanicError(err, "parse --faketime failed")
			}
			args.shift = time.Duration(n*int64(time.Millisecond) - time.Now().UnixNano())
		default:
			t, err := time.Parse("2006-01-02 15:04:05", s)
			if err != nil {
				log.PanicError(err, "parse --faketime failed")
			}
			args.shift = time.Duration(t.UnixNano() - time.Now().UnixNano())
		}
	}

	if s, ok := d["--filterdb"].(string); ok && s != "" && s != "*" {
		n, err := parseInt(s, MinDB, MaxDB)
		if err != nil {
			log.PanicError(err, "parse --filterdb failed")
		}
		u := uint32(n)
		acceptDB = func(db uint32) bool {
			return db == u
		}
	}

	if s, ok := d["--filesize"].(string); ok && s != "" {
		if len(args.sockfile) == 0 {
			log.Panic("please specify --sockfile first")
		}
//.........这里部分代码省略.........

func (cmd *cmdDecode) decoderMain(ipipe <-chan *rdb.BinEntry, opipe chan<- string) {
	toText := func(p []byte) string {
		var b bytes.Buffer
		for _, c := range p {
			switch {
			case c >= '#' && c <= '~':
				b.WriteByte(c)
			default:
				b.WriteByte('.')
			}
		}
		return b.String()
	}
	toBase64 := func(p []byte) string {
		return base64.StdEncoding.EncodeToString(p)
	}
	toJson := func(o interface{}) string {
		b, err := json.Marshal(o)
		if err != nil {
			log.PanicError(err, "encode to json failed")
		}
		return string(b)
	}
	for e := range ipipe {
		o, err := rdb.DecodeDump(e.Value)
		if err != nil {
			log.PanicError(err, "decode failed")
		}
		var b bytes.Buffer
		switch obj := o.(type) {
		default:
			log.Panicf("unknown object %v", o)
		case rdb.String:
			o := &struct {
				DB       uint32 `json:"db"`
				Type     string `json:"type"`
				ExpireAt uint64 `json:"expireat"`
				Key      string `json:"key"`
				Key64    string `json:"key64"`
				Value64  string `json:"value64"`
			}{
				e.DB, "string", e.ExpireAt, toText(e.Key), toBase64(e.Key),
				toBase64(obj),
			}
			fmt.Fprintf(&b, "%s\n", toJson(o))
		case rdb.List:
			for i, ele := range obj {
				o := &struct {
					DB       uint32 `json:"db"`
					Type     string `json:"type"`
					ExpireAt uint64 `json:"expireat"`
					Key      string `json:"key"`
					Key64    string `json:"key64"`
					Index    int    `json:"index"`
					Value64  string `json:"value64"`
				}{
					e.DB, "list", e.ExpireAt, toText(e.Key), toBase64(e.Key),
					i, toBase64(ele),
				}
				fmt.Fprintf(&b, "%s\n", toJson(o))
			}
		case rdb.Hash:
			for _, ele := range obj {
				o := &struct {
					DB       uint32 `json:"db"`
					Type     string `json:"type"`
					ExpireAt uint64 `json:"expireat"`
					Key      string `json:"key"`
					Key64    string `json:"key64"`
					Field    string `json:"field"`
					Field64  string `json:"field64"`
					Value64  string `json:"value64"`
				}{
					e.DB, "hash", e.ExpireAt, toText(e.Key), toBase64(e.Key),
					toText(ele.Field), toBase64(ele.Field), toBase64(ele.Value),
				}
				fmt.Fprintf(&b, "%s\n", toJson(o))
			}
		case rdb.Set:
			for _, mem := range obj {
				o := &struct {
					DB       uint32 `json:"db"`
					Type     string `json:"type"`
					ExpireAt uint64 `json:"expireat"`
					Key      string `json:"key"`
					Key64    string `json:"key64"`
					Member   string `json:"member"`
					Member64 string `json:"member64"`
				}{
					e.DB, "set", e.ExpireAt, toText(e.Key), toBase64(e.Key),
					toText(mem), toBase64(mem),
				}
				fmt.Fprintf(&b, "%s\n", toJson(o))
			}
		case rdb.ZSet:
			for _, ele := range obj {
				o := &struct {
					DB       uint32  `json:"db"`
					Type     string  `json:"type"`
					ExpireAt uint64  `json:"expireat"`
//.........这里部分代码省略.........

func (cmd *cmdDecode) Main() {
	input, output := args.input, args.output
	if len(input) == 0 {
		input = "/dev/stdin"
	}
	if len(output) == 0 {
		output = "/dev/stdout"
	}

	log.Infof("decode from '%s' to '%s'\n", input, output)

	var readin io.ReadCloser
	var nsize int64
	if input != "/dev/stdin" {
		readin, nsize = openReadFile(input)
		defer readin.Close()
	} else {
		readin, nsize = os.Stdin, 0
	}

	var saveto io.WriteCloser
	if output != "/dev/stdout" {
		saveto = openWriteFile(output)
		defer saveto.Close()
	} else {
		saveto = os.Stdout
	}

	reader := bufio.NewReaderSize(readin, ReaderBufferSize)
	writer := bufio.NewWriterSize(saveto, WriterBufferSize)

	ipipe := newRDBLoader(reader, &cmd.rbytes, args.parallel*32)
	opipe := make(chan string, cap(ipipe))

	go func() {
		defer close(opipe)
		group := make(chan int, args.parallel)
		for i := 0; i < cap(group); i++ {
			go func() {
				defer func() {
					group <- 0
				}()
				cmd.decoderMain(ipipe, opipe)
			}()
		}
		for i := 0; i < cap(group); i++ {
			<-group
		}
	}()

	wait := make(chan struct{})
	go func() {
		defer close(wait)
		for s := range opipe {
			cmd.wbytes.Add(int64(len(s)))
			if _, err := writer.WriteString(s); err != nil {
				log.PanicError(err, "write string failed")
			}
			flushWriter(writer)
		}
	}()

	for done := false; !done; {
		select {
		case <-wait:
			done = true
		case <-time.After(time.Second):
		}
		stat := cmd.Stat()
		var b bytes.Buffer
		fmt.Fprintf(&b, "decode: ")
		if nsize != 0 {
			fmt.Fprintf(&b, "total = %d - %12d [%3d%%]", nsize, stat.rbytes, 100*stat.rbytes/nsize)
		} else {
			fmt.Fprintf(&b, "total = %12d", stat.rbytes)
		}
		fmt.Fprintf(&b, "  write=%-12d", stat.wbytes)
		fmt.Fprintf(&b, "  entry=%-12d", stat.nentry)
		log.Info(b.String())
	}
	log.Info("decode: done")
}

func MustNoError(err error) {
	if err == nil {
		return
	}
	log.PanicError(err, "error happens, assertion failed")
}