mirror of https://github.com/tidwall/redcon.git
315 lines
8.2 KiB
Go
315 lines
8.2 KiB
Go
package redcon
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import (
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"strconv"
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"strings"
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)
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// Kind is the kind of command
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type Kind int
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const (
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// Redis is returned for Redis protocol commands
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Redis Kind = iota
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// Tile38 is returnd for Tile38 native protocol commands
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Tile38
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// Telnet is returnd for plain telnet commands
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Telnet
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)
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var errInvalidMessage = &errProtocol{"invalid message"}
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// ReadNextCommand reads the next command from the provided packet. It's
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// possible that the packet contains multiple commands, or zero commands
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// when the packet is incomplete.
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// 'argsbuf' is an optional reusable buffer and it can be nil.
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// 'complete' indicates that a command was read. false means no more commands.
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// 'args' are the output arguments for the command.
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// 'kind' is the type of command that was read.
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// 'leftover' is any remaining unused bytes which belong to the next command.
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// 'err' is returned when a protocol error was encountered.
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func ReadNextCommand(packet []byte, argsbuf [][]byte) (
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complete bool, args [][]byte, kind Kind, leftover []byte, err error,
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) {
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args = argsbuf[:0]
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if len(packet) > 0 {
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if packet[0] != '*' {
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if packet[0] == '$' {
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return readTile38Command(packet, args)
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}
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return readTelnetCommand(packet, args)
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}
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// standard redis command
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for s, i := 1, 1; i < len(packet); i++ {
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if packet[i] == '\n' {
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if packet[i-1] != '\r' {
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return false, args[:0], Redis, packet, errInvalidMultiBulkLength
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}
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count, ok := parseInt(packet[s : i-1])
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if !ok || count < 0 {
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return false, args[:0], Redis, packet, errInvalidMultiBulkLength
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}
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i++
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if count == 0 {
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return true, args[:0], Redis, packet[i:], nil
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}
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nextArg:
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for j := 0; j < count; j++ {
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if i == len(packet) {
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break
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}
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if packet[i] != '$' {
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return false, args[:0], Redis, packet,
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&errProtocol{"expected '$', got '" +
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string(packet[i]) + "'"}
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}
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for s := i + 1; i < len(packet); i++ {
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if packet[i] == '\n' {
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if packet[i-1] != '\r' {
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return false, args[:0], Redis, packet, errInvalidBulkLength
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}
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n, ok := parseInt(packet[s : i-1])
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if !ok || count <= 0 {
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return false, args[:0], Redis, packet, errInvalidBulkLength
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}
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i++
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if len(packet)-i >= n+2 {
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if packet[i+n] != '\r' || packet[i+n+1] != '\n' {
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return false, args[:0], Redis, packet, errInvalidBulkLength
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}
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args = append(args, packet[i:i+n])
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i += n + 2
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if j == count-1 {
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// done reading
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return true, args, Redis, packet[i:], nil
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}
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continue nextArg
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}
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break
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}
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}
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break
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}
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break
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}
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}
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}
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return false, args[:0], Redis, packet, nil
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}
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func readTile38Command(packet []byte, argsbuf [][]byte) (
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complete bool, args [][]byte, kind Kind, leftover []byte, err error,
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) {
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for i := 1; i < len(packet); i++ {
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if packet[i] == ' ' {
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n, ok := parseInt(packet[1:i])
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if !ok || n < 0 {
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return false, args[:0], Tile38, packet, errInvalidMessage
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}
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i++
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if len(packet) >= i+n+2 {
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if packet[i+n] != '\r' || packet[i+n+1] != '\n' {
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return false, args[:0], Tile38, packet, errInvalidMessage
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}
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line := packet[i : i+n]
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reading:
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for len(line) != 0 {
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if line[0] == '{' {
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// The native protocol cannot understand json boundaries so it assumes that
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// a json element must be at the end of the line.
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args = append(args, line)
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break
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}
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if line[0] == '"' && line[len(line)-1] == '"' {
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if len(args) > 0 &&
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strings.ToLower(string(args[0])) == "set" &&
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strings.ToLower(string(args[len(args)-1])) == "string" {
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// Setting a string value that is contained inside double quotes.
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// This is only because of the boundary issues of the native protocol.
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args = append(args, line[1:len(line)-1])
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break
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}
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}
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i := 0
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for ; i < len(line); i++ {
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if line[i] == ' ' {
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value := line[:i]
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if len(value) > 0 {
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args = append(args, value)
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}
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line = line[i+1:]
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continue reading
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}
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}
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args = append(args, line)
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break
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}
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return true, args, Tile38, packet[i+n+2:], nil
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}
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break
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}
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}
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return false, args[:0], Tile38, packet, nil
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}
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func readTelnetCommand(packet []byte, argsbuf [][]byte) (
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complete bool, args [][]byte, kind Kind, leftover []byte, err error,
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) {
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// just a plain text command
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for i := 0; i < len(packet); i++ {
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if packet[i] == '\n' {
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var line []byte
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if i > 0 && packet[i-1] == '\r' {
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line = packet[:i-1]
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} else {
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line = packet[:i]
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}
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var quote bool
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var quotech byte
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var escape bool
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outer:
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for {
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nline := make([]byte, 0, len(line))
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for i := 0; i < len(line); i++ {
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c := line[i]
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if !quote {
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if c == ' ' {
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if len(nline) > 0 {
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args = append(args, nline)
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}
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line = line[i+1:]
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continue outer
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}
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if c == '"' || c == '\'' {
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if i != 0 {
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return false, args[:0], Telnet, packet, errUnbalancedQuotes
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}
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quotech = c
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quote = true
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line = line[i+1:]
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continue outer
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}
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} else {
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if escape {
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escape = false
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switch c {
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case 'n':
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c = '\n'
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case 'r':
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c = '\r'
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case 't':
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c = '\t'
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}
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} else if c == quotech {
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quote = false
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quotech = 0
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args = append(args, nline)
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line = line[i+1:]
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if len(line) > 0 && line[0] != ' ' {
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return false, args[:0], Telnet, packet, errUnbalancedQuotes
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}
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continue outer
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} else if c == '\\' {
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escape = true
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continue
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}
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}
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nline = append(nline, c)
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}
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if quote {
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return false, args[:0], Telnet, packet, errUnbalancedQuotes
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}
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if len(line) > 0 {
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args = append(args, line)
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}
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break
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}
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return true, args, Telnet, packet[i+1:], nil
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}
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}
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return false, args[:0], Telnet, packet, nil
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}
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// appendPrefix will append a "$3\r\n" style redis prefix for a message.
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func appendPrefix(b []byte, c byte, n int64) []byte {
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if n >= 0 && n <= 9 {
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return append(b, c, byte('0'+n), '\r', '\n')
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}
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b = append(b, c)
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b = strconv.AppendInt(b, n, 10)
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return append(b, '\r', '\n')
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}
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// AppendUint appends a Redis protocol uint64 to the input bytes.
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func AppendUint(b []byte, n uint64) []byte {
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b = append(b, ':')
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b = strconv.AppendUint(b, n, 10)
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return append(b, '\r', '\n')
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}
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// AppendInt appends a Redis protocol int64 to the input bytes.
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func AppendInt(b []byte, n int64) []byte {
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return appendPrefix(b, ':', n)
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}
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// AppendArray appends a Redis protocol array to the input bytes.
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func AppendArray(b []byte, n int) []byte {
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return appendPrefix(b, '*', int64(n))
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}
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// AppendBulk appends a Redis protocol bulk byte slice to the input bytes.
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func AppendBulk(b []byte, bulk []byte) []byte {
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b = appendPrefix(b, '$', int64(len(bulk)))
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b = append(b, bulk...)
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return append(b, '\r', '\n')
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}
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// AppendBulkString appends a Redis protocol bulk string to the input bytes.
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func AppendBulkString(b []byte, bulk string) []byte {
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b = appendPrefix(b, '$', int64(len(bulk)))
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b = append(b, bulk...)
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return append(b, '\r', '\n')
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}
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// AppendString appends a Redis protocol string to the input bytes.
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func AppendString(b []byte, s string) []byte {
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b = append(b, '+')
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b = append(b, stripNewlines(s)...)
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return append(b, '\r', '\n')
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}
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// AppendError appends a Redis protocol error to the input bytes.
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func AppendError(b []byte, s string) []byte {
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b = append(b, '-')
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b = append(b, stripNewlines(s)...)
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return append(b, '\r', '\n')
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}
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// AppendOK appends a Redis protocol OK to the input bytes.
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func AppendOK(b []byte) []byte {
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return append(b, '+', 'O', 'K', '\r', '\n')
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}
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func stripNewlines(s string) string {
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for i := 0; i < len(s); i++ {
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if s[i] == '\r' || s[i] == '\n' {
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s = strings.Replace(s, "\r", " ", -1)
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s = strings.Replace(s, "\n", " ", -1)
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break
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}
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}
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return s
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}
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// AppendTile38 appends a Tile38 message to the input bytes.
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func AppendTile38(b []byte, data []byte) []byte {
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b = append(b, '$')
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b = strconv.AppendInt(b, int64(len(data)), 10)
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b = append(b, ' ')
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b = append(b, data...)
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return append(b, '\r', '\n')
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}
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// AppendNull appends a Redis protocol null to the input bytes.
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func AppendNull(b []byte) []byte {
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return append(b, '$', '-', '1', '\r', '\n')
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}
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