Golang streambuf.Buffer類代碼示例

func (p *parser) parseString(buf *streambuf.Buffer) (string, bool, bool) {
	line, err := buf.UntilCRLF()
	if err != nil {
		return "", true, false
	}

	if len(line) == 3 && line[1] == '-' && line[2] == '1' {
		return "nil", true, true
	}

	length, err := strconv.ParseInt(string(line[1:]), 10, 64)
	if err != nil {
		logp.Err("Failed to read bulk message: %s", err)
		return "", false, false
	}

	content, err := buf.CollectWithSuffix(int(length), []byte("\r\n"))
	if err != nil {
		if err != streambuf.ErrNoMoreBytes {
			return "", false, false
		}
		return "", true, false
	}

	return string(content), true, true
}

func (p *parser) dispatch(depth int, buf *streambuf.Buffer) (string, bool, bool, bool) {
	if buf.Len() == 0 {
		return "", false, true, false
	}

	var value string
	var iserror, ok, complete bool
	snapshot := buf.Snapshot()

	switch buf.Bytes()[0] {
	case '*':
		value, iserror, ok, complete = p.parseArray(depth, buf)
	case '$':
		value, ok, complete = p.parseString(buf)
	case ':':
		value, ok, complete = p.parseInt(buf)
	case '+':
		value, ok, complete = p.parseSimpleString(buf)
	case '-':
		iserror = true
		value, ok, complete = p.parseSimpleString(buf)
	default:
		debug("Unexpected message starting with %s", buf.Bytes()[0])
		return "", false, false, false
	}

	if !ok || !complete {
		buf.Restore(snapshot)
	}
	return value, iserror, ok, complete
}

func (p *parser) parseSimpleString(buf *streambuf.Buffer) (string, bool, bool) {
	line, err := buf.UntilCRLF()
	if err != nil {
		return "", true, false
	}

	return string(line[1:]), true, true
}

func (p *parser) parseArray(depth int, buf *streambuf.Buffer) (string, bool, bool, bool) {
	line, err := buf.UntilCRLF()
	if err != nil {
		debug("End of line not found, waiting for more data")
		return "", false, false, false
	}
	debug("line %s: %d", line, buf.BufferConsumed())

	if len(line) == 3 && line[1] == '-' && line[2] == '1' {
		return "nil", false, true, true
	}

	if len(line) == 2 && line[1] == '0' {
		return "[]", false, true, true
	}

	count, err := strconv.ParseInt(string(line[1:]), 10, 64)
	if err != nil {
		logp.Err("Failed to read number of bulk messages: %s", err)
		return "", false, false, false
	}
	if count < 0 {
		return "nil", false, true, true
	}

	content := make([]string, 0, count)
	// read sub elements

	iserror := false
	for i := 0; i < int(count); i++ {
		var value string
		var ok, complete bool

		value, iserror, ok, complete := p.dispatch(depth+1, buf)
		if !ok || !complete {
			debug("Array incomplete")
			return "", iserror, ok, complete
		}

		content = append(content, value)
	}

	if depth == 0 && isRedisCommand(content[0]) { // we've got a request
		p.message.IsRequest = true
		p.message.Method = content[0]
		p.message.Path = content[1]
	}

	var value string
	if depth == 0 && p.message.IsRequest {
		value = strings.Join(content, " ")
	} else {
		value = "[" + strings.Join(content, ", ") + "]"
	}
	return value, iserror, true, true
}

func withBinaryUint64(
	parser *parser,
	buf *streambuf.Buffer,
	f func(*message, uint64),
) error {
	val, err := buf.ReadNetUint64()
	if err == nil {
		f(parser.message, val)
	}
	return err
}

func withInt64Arg(
	parser *parser,
	buf *streambuf.Buffer,
	fn func(msg *message, v int64),
) error {
	parseNextArg(buf)
	value, err := buf.AsciiInt(false)
	if err == nil {
		fn(parser.message, value)
	}
	return textArgError(err)
}

func parseVersionNumber(parser *parser, buf *streambuf.Buffer) parseResult {
	msg := parser.message
	if msg.IsRequest {
		return parser.contWith(buf, parseStateDataBinary)
	}

	// size already checked
	bytes, _ := buf.Collect(int(msg.bytes))
	msg.str = memcacheString{bytes}

	return parser.yield(buf.BufferConsumed())
}

func doParseCommand(parser *parser, buf *streambuf.Buffer) parseResult {
	// check if binary + text command and dispatch
	if !buf.Avail(2) {
		return parser.needMore()
	}
	magic := buf.Bytes()[0]
	is_binary := magic == MemcacheMagicRequest || magic == MemcacheMagicResponse
	if is_binary {
		return parser.contWith(buf, parseStateBinaryCommand)
	} else {
		return parser.contWith(buf, parseStateTextCommand)
	}
}

func withUintArg(
	parser *parser,
	buf *streambuf.Buffer,
	fn func(msg *message, v uint32),
) error {
	msg := parser.message
	parseNextArg(buf)
	value, err := buf.AsciiUint(false)
	if err == nil {
		fn(msg, uint32(value))
	}
	return textArgError(err)
}

func (p *parser) parseInt(buf *streambuf.Buffer) (string, bool, bool) {
	line, err := buf.UntilCRLF()
	if err != nil {
		return "", true, false
	}

	number := string(line[1:])
	if _, err := strconv.ParseInt(number, 10, 64); err != nil {
		logp.Err("Failed to read integer reply: %s", err)
	}

	return number, true, true
}

func parseStatLine(parser *parser, hdr, buf *streambuf.Buffer) error {
	name, _ := parseStringArg(buf)
	value, _ := parseStringArg(buf)
	if buf.Failed() {
		return buf.Err()
	}

	msg := parser.message
	msg.stats = append(msg.stats, memcacheStat{
		memcacheString{name},
		memcacheString{value},
	})
	return nil
}

func doParseTextCommand(parser *parser, buf *streambuf.Buffer) parseResult {
	line, err := buf.UntilCRLF()
	if err != nil {
		if err == streambuf.ErrNoMoreBytes {
			return parser.needMore()
		}
		return parser.failing(err)
	}

	msg := parser.message
	command, args, err := splitCommandAndArgs(line)
	if err != nil {
		return parser.failing(err)
	}

	debug("parse command: '%s' '%s'", command, args)

	msg.IsRequest = 'a' <= command[0] && command[0] <= 'z'
	var cmd *textCommandType
	if msg.IsRequest {
		cmd = findTextCommandType(requestCommands, command)
	} else {
		cmd = findTextCommandType(responseCommands, command)
		if cmd == nil {
			b := command[0]
			if '0' <= b && b <= '9' {
				cmd = &counterResponse
			}
		}
	}
	if cmd == nil {
		debug("unknown command: %s", msg.command)
		if parser.config.parseUnkown {
			cmd = &unknownCommand
		} else {
			return parser.failing(ErrParserUnknownCommand)
		}
	}

	msg.command = &cmd.commandType
	msg.rawArgs = args
	msg.commandLine = memcacheString{line}
	msg.rawCommand = command

	// the command parser will work on already separated command line.
	// The parser will either yield a message directly, or switch to binary
	// data parsing mode, which is provided by explicit state
	return parser.contWithShallow(buf, cmd.parse)
}

func sockReadMessage(buf *streambuf.Buffer, in io.Reader) (*message, error) {
	buffer := make([]byte, 1024)
	for {
		n, err := in.Read(buffer)
		if err != nil {
			return nil, err
		}

		buf.Write(buffer[:n])
		msg, err := readMessage(buf)
		if msg != nil || err != nil {
			return msg, err
		}
	}
}

func parseNoReplyArg(buf *streambuf.Buffer) (bool, error) {
	debug("parse noreply")

	err := parseNextArg(buf)
	if err != nil {
		return false, textArgError(err)
	}

	var noreplyArg = []byte("noreply")
	noreply := bytes.HasPrefix(buf.Bytes(), noreplyArg)
	if !noreply {
		return false, ErrExpectedNoReply
	}
	return true, nil
}

func parseUdpHeader(buf *streambuf.Buffer) (mcUdpHeader, error) {
	var h mcUdpHeader
	h.requestId, _ = buf.ReadNetUint16()
	h.seqNumber, _ = buf.ReadNetUint16()
	h.numDatagrams, _ = buf.ReadNetUint16()
	buf.Advance(2) // ignore reserved
	return h, buf.Err()
}