refactor redis protocol parser

This commit is contained in:
finley
2022-11-08 22:11:39 +08:00
parent 1459f3de01
commit 72c263969c

View File

@@ -4,13 +4,13 @@ import (
"bufio"
"bytes"
"errors"
"fmt"
"github.com/hdt3213/godis/interface/redis"
"github.com/hdt3213/godis/lib/logger"
"github.com/hdt3213/godis/redis/protocol"
"io"
"runtime/debug"
"strconv"
"strings"
)
// Payload stores redis.Reply or error
@@ -59,234 +59,134 @@ func ParseOne(data []byte) (redis.Reply, error) {
return payload.Data, payload.Err
}
type readState struct {
readingMultiLine bool
expectedArgsCount int
msgType byte
args [][]byte
bulkLen int64
readingRepl bool
}
func (s *readState) finished() bool {
return s.expectedArgsCount > 0 && len(s.args) == s.expectedArgsCount
}
func parse0(reader io.Reader, ch chan<- *Payload) {
func parse0(rawReader io.Reader, ch chan<- *Payload) {
defer func() {
if err := recover(); err != nil {
logger.Error(err, string(debug.Stack()))
close(ch)
}
}()
bufReader := bufio.NewReader(reader)
var state readState
var err error
var msg []byte
reader := bufio.NewReader(rawReader)
for {
// read line
var ioErr bool
msg, ioErr, err = readLine(bufReader, &state)
line, err := reader.ReadBytes('\n')
if err != nil {
ch <- &Payload{Err: err}
if ioErr { // encounter io err, stop read
close(ch)
return
}
length := len(line)
if length <= 2 || line[length-2] != '\r' {
protocolError(ch, line)
continue
}
line = bytes.TrimSuffix(line, []byte{'\r', '\n'})
switch line[0] {
case '+':
ch <- &Payload{
Data: protocol.MakeStatusReply(string(line[1:])),
}
case '-':
ch <- &Payload{
Data: protocol.MakeErrReply(string(line[1:])),
}
case ':':
value, err := strconv.ParseInt(string(line[1:]), 10, 64)
if err != nil {
protocolError(ch, line)
continue
}
ch <- &Payload{
Data: protocol.MakeIntReply(value),
}
case '$':
err = parseBulkString(line, reader, ch)
if err != nil {
ch <- &Payload{Err: err}
close(ch)
return
}
// protocol err, reset read state
state = readState{}
continue
}
// parse line
if !state.readingMultiLine {
// receive new response
if msg[0] == '*' {
// multi bulk protocol
err = parseMultiBulkHeader(msg, &state)
if err != nil {
ch <- &Payload{
Err: errors.New("protocol error: " + string(msg)),
}
state = readState{} // reset state
continue
}
if state.expectedArgsCount == 0 {
ch <- &Payload{
Data: &protocol.EmptyMultiBulkReply{},
}
state = readState{} // reset state
continue
}
} else if msg[0] == '$' { // bulk protocol
err = parseBulkHeader(msg, &state)
if err != nil {
ch <- &Payload{
Err: errors.New("protocol error: " + string(msg)),
}
state = readState{} // reset state
continue
}
if state.bulkLen == -1 { // null bulk protocol
ch <- &Payload{
Data: &protocol.NullBulkReply{},
}
state = readState{} // reset state
continue
}
} else {
// single line protocol
result, err := parseSingleLineReply(msg)
ch <- &Payload{
Data: result,
Err: err,
}
state = readState{} // reset state
continue
}
} else {
// receive following bulk protocol
err = readBody(msg, &state)
case '*':
err = parseArray(line, reader, ch)
if err != nil {
ch <- &Payload{
Err: errors.New("protocol error: " + string(msg)),
}
state = readState{} // reset state
continue
ch <- &Payload{Err: err}
close(ch)
return
}
// if sending finished
if state.finished() {
var result redis.Reply
if state.msgType == '*' {
result = protocol.MakeMultiBulkReply(state.args)
} else if state.msgType == '$' {
result = protocol.MakeBulkReply(state.args[0])
}
ch <- &Payload{
Data: result,
Err: err,
}
state = readState{}
default:
args := bytes.Split(line, []byte{' '})
ch <- &Payload{
Data: protocol.MakeMultiBulkReply(args),
}
}
}
}
func readLine(bufReader *bufio.Reader, state *readState) ([]byte, bool, error) {
var msg []byte
var err error
if state.bulkLen == 0 { // read normal line
msg, err = bufReader.ReadBytes('\n')
if err != nil {
return nil, true, err
func parseBulkString(header []byte, reader *bufio.Reader, ch chan<- *Payload) error {
strLen, err := strconv.ParseInt(string(header[1:]), 10, 64)
if err != nil || strLen < -1 {
protocolError(ch, header)
return nil
} else if strLen == -1 {
ch <- &Payload{
Data: protocol.MakeNullBulkReply(),
}
if len(msg) == 0 || msg[len(msg)-2] != '\r' {
return nil, false, errors.New("protocol error: " + string(msg))
}
} else { // read bulk line (binary safe)
// there is CRLF between BulkReply in normal stream
// but there is no CRLF between RDB and following AOF
bulkLen := state.bulkLen + 2
if state.readingRepl {
bulkLen -= 2
}
msg = make([]byte, bulkLen)
_, err = io.ReadFull(bufReader, msg)
if err != nil {
return nil, true, err
}
//if len(msg) == 0 ||
// msg[len(msg)-2] != '\r' ||
// msg[len(msg)-1] != '\n' {
// return nil, false, errors.New("protocol error: " + string(msg))
//}
state.bulkLen = 0
return nil
}
return msg, false, nil
}
func parseMultiBulkHeader(msg []byte, state *readState) error {
var err error
var expectedLine uint64
expectedLine, err = strconv.ParseUint(string(msg[1:len(msg)-2]), 10, 32)
body := make([]byte, strLen+2)
_, err = io.ReadFull(reader, body)
if err != nil {
return errors.New("protocol error: " + string(msg))
return err
}
if expectedLine == 0 {
state.expectedArgsCount = 0
return nil
} else if expectedLine > 0 {
// first line of multi bulk protocol
state.msgType = msg[0]
state.readingMultiLine = true
state.expectedArgsCount = int(expectedLine)
state.args = make([][]byte, 0, expectedLine)
return nil
}
return errors.New("protocol error: " + string(msg))
}
func parseBulkHeader(msg []byte, state *readState) error {
var err error
state.bulkLen, err = strconv.ParseInt(string(msg[1:len(msg)-2]), 10, 64)
if err != nil {
return errors.New("protocol error: " + string(msg))
}
if state.bulkLen == -1 { // null bulk
return nil
} else if state.bulkLen >= 0 {
state.msgType = msg[0]
state.readingMultiLine = true
state.expectedArgsCount = 1
state.args = make([][]byte, 0, 1)
return nil
}
return errors.New("protocol error: " + string(msg))
}
func parseSingleLineReply(msg []byte) (redis.Reply, error) {
str := strings.TrimSuffix(string(msg), "\r\n")
var result redis.Reply
switch msg[0] {
case '+': // status protocol
result = protocol.MakeStatusReply(str[1:])
case '-': // err protocol
result = protocol.MakeErrReply(str[1:])
case ':': // int protocol
val, err := strconv.ParseInt(str[1:], 10, 64)
if err != nil {
return nil, errors.New("protocol error: " + string(msg))
}
result = protocol.MakeIntReply(val)
default:
// parse as text protocol
strs := strings.Split(str, " ")
args := make([][]byte, len(strs))
for i, s := range strs {
args[i] = []byte(s)
}
result = protocol.MakeMultiBulkReply(args)
}
return result, nil
}
// read the non-first lines of multi bulk protocol or bulk protocol
func readBody(msg []byte, state *readState) error {
line := msg[0 : len(msg)-2]
var err error
if len(line) > 0 && line[0] == '$' {
// bulk protocol
state.bulkLen, err = strconv.ParseInt(string(line[1:]), 10, 64)
if err != nil {
return errors.New("protocol error: " + string(msg))
}
if state.bulkLen < 0 { // null bulk in multi bulks
state.args = append(state.args, []byte{})
state.bulkLen = 0
}
} else {
state.args = append(state.args, line)
ch <- &Payload{
Data: protocol.MakeBulkReply(body[:len(body)-2]),
}
return nil
}
func parseArray(header []byte, reader *bufio.Reader, ch chan<- *Payload) error {
nStrs, err := strconv.ParseInt(string(header[1:]), 10, 64)
if err != nil || nStrs < 0 {
protocolError(ch, header)
return nil
} else if nStrs == 0 {
ch <- &Payload{
Data: protocol.MakeEmptyMultiBulkReply(),
}
return nil
}
lines := make([][]byte, 0, nStrs)
for i := int64(0); i < nStrs; i++ {
var line []byte
line, err = reader.ReadBytes('\n')
if err != nil {
return err
}
length := len(line)
if length < 4 || line[length-2] != '\r' || line[0] != '$' {
protocolError(ch, line)
break
}
strLen, err := strconv.ParseInt(string(line[1:length-2]), 10, 64)
if err != nil || strLen < -1 {
protocolError(ch, header)
break
} else if strLen == -1 {
lines = append(lines, []byte{})
} else {
body := make([]byte, strLen+2)
_, err := io.ReadFull(reader, body)
if err != nil {
return err
}
lines = append(lines, body[:len(body)-2])
}
}
ch <- &Payload{
Data: protocol.MakeMultiBulkReply(lines),
}
return nil
}
func protocolError(ch chan<- *Payload, msg []byte) {
err := errors.New(fmt.Sprintf("Protocol error: %s", string(msg)))
ch <- &Payload{Err: err}
}