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RespCommand.cs
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// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.
using System;
using System.Diagnostics;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
using Garnet.common;
using Microsoft.Extensions.Logging;
namespace Garnet.server
{
/// <summary>
/// Basic RESP command enum
/// </summary>
public enum RespCommand : ushort
{
NONE = 0x00,
// Read-only commands. NOTE: Should immediately follow NONE.
BITCOUNT,
BITFIELD_RO,
BITPOS,
COSCAN,
DBSIZE,
DUMP,
EXISTS,
EXPIRETIME,
GEODIST,
GEOHASH,
GEOPOS,
GEOSEARCH,
GET,
GETBIT,
GETIFNOTMATCH,
GETRANGE,
GETWITHETAG,
HEXISTS,
HGET,
HGETALL,
HKEYS,
HLEN,
HMGET,
HRANDFIELD,
HSCAN,
HSTRLEN,
HVALS,
KEYS,
LCS,
HTTL,
HPTTL,
HEXPIRETIME,
HPEXPIRETIME,
LINDEX,
LLEN,
LPOS,
LRANGE,
MEMORY_USAGE,
MGET,
PEXPIRETIME,
PFCOUNT,
PTTL,
SCAN,
SCARD,
SDIFF,
SINTER,
SINTERCARD,
SISMEMBER,
SMEMBERS,
SMISMEMBER,
SPUBLISH,
SRANDMEMBER,
SSCAN,
SSUBSCRIBE,
STRLEN,
SUBSTR,
SUNION,
TTL,
TYPE,
WATCH,
WATCHMS,
WATCHOS,
ZCARD,
ZCOUNT,
ZDIFF,
ZINTER,
ZINTERCARD,
ZLEXCOUNT,
ZMSCORE,
ZRANDMEMBER,
ZRANGE,
ZRANGEBYLEX,
ZRANGEBYSCORE,
ZRANK,
ZREVRANGE,
ZREVRANGEBYLEX,
ZREVRANGEBYSCORE,
ZREVRANK,
ZSCAN,
ZSCORE, // Note: Last read command should immediately precede FirstWriteCommand
ZUNION,
// Write commands
APPEND, // Note: Update FirstWriteCommand if adding new write commands before this
BITFIELD,
BZMPOP,
BZPOPMAX,
BZPOPMIN,
DECR,
DECRBY,
DEL,
EXPIRE,
EXPIREAT,
FLUSHALL,
FLUSHDB,
GEOADD,
GEOSEARCHSTORE,
GETDEL,
GETEX,
GETSET,
HCOLLECT,
HDEL,
HEXPIRE,
HPEXPIRE,
HEXPIREAT,
HPEXPIREAT,
HPERSIST,
HINCRBY,
HINCRBYFLOAT,
HMSET,
HSET,
HSETNX,
INCR,
INCRBY,
INCRBYFLOAT,
LINSERT,
LMOVE,
LMPOP,
LPOP,
LPUSH,
LPUSHX,
LREM,
LSET,
LTRIM,
BLPOP,
BRPOP,
BLMOVE,
BRPOPLPUSH,
BLMPOP,
MIGRATE,
MSET,
MSETNX,
PERSIST,
PEXPIRE,
PEXPIREAT,
PFADD,
PFMERGE,
PSETEX,
RENAME,
RESTORE,
RENAMENX,
RPOP,
RPOPLPUSH,
RPUSH,
RPUSHX,
SADD,
SDIFFSTORE,
SET,
SETBIT,
SETEX,
SETEXNX,
SETEXXX,
SETNX,
SETIFMATCH,
SETKEEPTTL,
SETKEEPTTLXX,
SETRANGE,
SINTERSTORE,
SMOVE,
SPOP,
SREM,
SUNIONSTORE,
UNLINK,
ZADD,
ZDIFFSTORE,
ZINCRBY,
ZMPOP,
ZINTERSTORE,
ZPOPMAX,
ZPOPMIN,
ZRANGESTORE,
ZREM,
ZREMRANGEBYLEX,
ZREMRANGEBYRANK,
ZREMRANGEBYSCORE,
ZUNIONSTORE,
// BITOP is the true command, AND|OR|XOR|NOT are pseudo-subcommands
BITOP,
BITOP_AND,
BITOP_OR,
BITOP_XOR,
BITOP_NOT, // Note: Update LastWriteCommand if adding new write commands after this
// Script execution commands
EVAL,
EVALSHA, // Note: Update LastDataCommand if adding new data commands after this
// Neither read nor write key commands
ASYNC,
PING,
// Pub/Sub commands
PUBSUB,
PUBSUB_CHANNELS,
PUBSUB_NUMPAT,
PUBSUB_NUMSUB,
PUBLISH,
SUBSCRIBE,
PSUBSCRIBE,
UNSUBSCRIBE,
PUNSUBSCRIBE,
ASKING,
SELECT,
ECHO,
CLIENT,
CLIENT_ID,
CLIENT_INFO,
CLIENT_LIST,
CLIENT_KILL,
CLIENT_GETNAME,
CLIENT_SETNAME,
CLIENT_SETINFO,
CLIENT_UNBLOCK,
MONITOR,
MODULE,
MODULE_LOADCS,
REGISTERCS,
MULTI,
EXEC,
DISCARD,
UNWATCH,
RUNTXP,
READONLY,
READWRITE,
REPLICAOF,
SECONDARYOF,
INFO,
TIME,
ROLE,
SAVE,
LASTSAVE,
BGSAVE,
COMMITAOF,
FORCEGC,
PURGEBP,
FAILOVER,
// Custom commands
CustomTxn,
CustomRawStringCmd,
CustomObjCmd,
CustomProcedure,
// Script commands
SCRIPT,
SCRIPT_EXISTS,
SCRIPT_FLUSH,
SCRIPT_LOAD,
ACL,
ACL_CAT,
ACL_DELUSER,
ACL_LIST,
ACL_LOAD,
ACL_SAVE,
ACL_SETUSER,
ACL_USERS,
ACL_WHOAMI,
COMMAND,
COMMAND_COUNT,
COMMAND_DOCS,
COMMAND_INFO,
COMMAND_GETKEYS,
COMMAND_GETKEYSANDFLAGS,
MEMORY,
// MEMORY_USAGE is a read-only command, so moved up
CONFIG,
CONFIG_GET,
CONFIG_REWRITE,
CONFIG_SET,
DEBUG,
LATENCY,
LATENCY_HELP,
LATENCY_HISTOGRAM,
LATENCY_RESET,
// SLOWLOG commands
SLOWLOG,
SLOWLOG_HELP,
SLOWLOG_LEN,
SLOWLOG_GET,
SLOWLOG_RESET,
CLUSTER,
CLUSTER_ADDSLOTS, // Note: Update IsClusterSubCommand if adding new cluster subcommands before this
CLUSTER_ADDSLOTSRANGE,
CLUSTER_AOFSYNC,
CLUSTER_APPENDLOG,
CLUSTER_BANLIST,
CLUSTER_BEGIN_REPLICA_RECOVER,
CLUSTER_BUMPEPOCH,
CLUSTER_COUNTKEYSINSLOT,
CLUSTER_DELKEYSINSLOT,
CLUSTER_DELKEYSINSLOTRANGE,
CLUSTER_DELSLOTS,
CLUSTER_DELSLOTSRANGE,
CLUSTER_ENDPOINT,
CLUSTER_FAILOVER,
CLUSTER_FAILREPLICATIONOFFSET,
CLUSTER_FAILSTOPWRITES,
CLUSTER_FORGET,
CLUSTER_GETKEYSINSLOT,
CLUSTER_GOSSIP,
CLUSTER_HELP,
CLUSTER_INFO,
CLUSTER_INITIATE_REPLICA_SYNC,
CLUSTER_KEYSLOT,
CLUSTER_MEET,
CLUSTER_MIGRATE,
CLUSTER_MTASKS,
CLUSTER_MYID,
CLUSTER_MYPARENTID,
CLUSTER_NODES,
CLUSTER_PUBLISH,
CLUSTER_SPUBLISH,
CLUSTER_REPLICAS,
CLUSTER_REPLICATE,
CLUSTER_RESET,
CLUSTER_SEND_CKPT_FILE_SEGMENT,
CLUSTER_SEND_CKPT_METADATA,
CLUSTER_SETCONFIGEPOCH,
CLUSTER_SETSLOT,
CLUSTER_SETSLOTSRANGE,
CLUSTER_SHARDS,
CLUSTER_SLOTS,
CLUSTER_SLOTSTATE, // Note: Update IsClusterSubCommand if adding new cluster subcommands after this
// Don't require AUTH (if auth is enabled)
AUTH, // Note: Update IsNoAuth if adding new no-auth commands before this
HELLO,
QUIT, // Note: Update IsNoAuth if adding new no-auth commands after this
// Max value of this enum (not including INVALID) will determine the size of RespCommand.AofIndependentBitLookup and CommandPermissionSet._commandList,
// so avoid manually setting high values unless necessary
INVALID = 0xFFFF,
}
/// <summary>
/// Extension methods for <see cref="RespCommand"/>.
/// </summary>
public static class RespCommandExtensions
{
private static readonly RespCommand[] ExpandedSET = [RespCommand.SETEXNX, RespCommand.SETEXXX, RespCommand.SETKEEPTTL, RespCommand.SETKEEPTTLXX];
private static readonly RespCommand[] ExpandedBITOP = [RespCommand.BITOP_AND, RespCommand.BITOP_NOT, RespCommand.BITOP_OR, RespCommand.BITOP_XOR];
// Commands that are either returning static data or commands that cannot have issues from concurrent AOF interaction in another session
private static readonly RespCommand[] AofIndependentCommands = [
RespCommand.ASYNC,
RespCommand.PING,
RespCommand.SELECT,
RespCommand.ECHO,
RespCommand.MONITOR,
RespCommand.MODULE_LOADCS,
RespCommand.REGISTERCS,
RespCommand.INFO,
RespCommand.TIME,
RespCommand.LASTSAVE,
// ACL
RespCommand.ACL_CAT,
RespCommand.ACL_DELUSER,
RespCommand.ACL_LIST,
RespCommand.ACL_LOAD,
RespCommand.ACL_SAVE,
RespCommand.ACL_SETUSER,
RespCommand.ACL_USERS,
RespCommand.ACL_WHOAMI,
// Client
RespCommand.CLIENT_ID,
RespCommand.CLIENT_INFO,
RespCommand.CLIENT_LIST,
RespCommand.CLIENT_KILL,
RespCommand.CLIENT_GETNAME,
RespCommand.CLIENT_SETNAME,
RespCommand.CLIENT_SETINFO,
RespCommand.CLIENT_UNBLOCK,
// Command
RespCommand.COMMAND,
RespCommand.COMMAND_COUNT,
RespCommand.COMMAND_DOCS,
RespCommand.COMMAND_INFO,
RespCommand.COMMAND_GETKEYS,
RespCommand.COMMAND_GETKEYSANDFLAGS,
RespCommand.MEMORY_USAGE,
// Config
RespCommand.CONFIG_GET,
RespCommand.CONFIG_REWRITE,
RespCommand.CONFIG_SET,
// Latency
RespCommand.LATENCY_HELP,
RespCommand.LATENCY_HISTOGRAM,
RespCommand.LATENCY_RESET,
// Slowlog
RespCommand.SLOWLOG_HELP,
RespCommand.SLOWLOG_LEN,
RespCommand.SLOWLOG_GET,
RespCommand.SLOWLOG_RESET,
// Transactions
RespCommand.MULTI,
];
private static readonly ulong[] AofIndependentBitLookup;
private const int sizeOfLong = 64;
// The static ctor maybe expensive but it is only ever run once, and doesn't interfere with common path
static RespCommandExtensions()
{
// # of bits needed to represent all valid commands
var maxBitsNeeded = (ushort)LastValidCommand + 1;
var lookupTableSize = (maxBitsNeeded / 64) + (maxBitsNeeded % 64 == 0 ? 0 : 1);
AofIndependentBitLookup = new ulong[lookupTableSize];
foreach (var cmd in Enum.GetValues<RespCommand>())
{
if (Array.IndexOf(AofIndependentCommands, cmd) == -1)
continue;
// mark the command as an AOF independent command for lookups later by setting the bit in bit vec
int bitIdxToUse = (int)cmd / sizeOfLong;
// set the respCommand's bit to indicate
int bitIdxOffset = (int)cmd % sizeOfLong;
ulong bitmask = 1UL << bitIdxOffset;
AofIndependentBitLookup[bitIdxToUse] |= bitmask;
}
}
/// <summary>
/// Returns whether or not a Resp command can have a dirty read or is dependent on AOF or not
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsAofIndependent(this RespCommand cmd)
{
if (cmd > LastValidCommand) return false;
// check if cmd maps to a bit vec that was set back when static ctor was run
int bitIdxToUse = (int)cmd / sizeOfLong;
int bitIdxOffset = (int)cmd % sizeOfLong;
ulong bitmask = 1UL << bitIdxOffset;
return (AofIndependentBitLookup[bitIdxToUse] & bitmask) != 0;
}
/// <summary>
/// Turns any not-quite-a-real-command entries in <see cref="RespCommand"/> into the equivalent command
/// for ACL'ing purposes and reading command info purposes
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static RespCommand NormalizeForACLs(this RespCommand cmd)
{
return
cmd switch
{
RespCommand.SETEXNX => RespCommand.SET,
RespCommand.SETEXXX => RespCommand.SET,
RespCommand.SETKEEPTTL => RespCommand.SET,
RespCommand.SETKEEPTTLXX => RespCommand.SET,
RespCommand.BITOP_AND or RespCommand.BITOP_NOT or RespCommand.BITOP_OR or RespCommand.BITOP_XOR => RespCommand.BITOP,
_ => cmd
};
}
/// <summary>
/// Reverses <see cref="NormalizeForACLs(RespCommand)"/>, producing all the equivalent <see cref="RespCommand"/>s which are covered by <paramref name="cmd"/>.
/// </summary>
public static ReadOnlySpan<RespCommand> ExpandForACLs(this RespCommand cmd)
{
return
cmd switch
{
RespCommand.SET => ExpandedSET,
RespCommand.BITOP => ExpandedBITOP,
_ => default
};
}
internal const RespCommand FirstReadCommand = RespCommand.NONE + 1;
internal const RespCommand LastReadCommand = RespCommand.APPEND - 1;
internal const RespCommand FirstWriteCommand = RespCommand.APPEND;
internal const RespCommand LastWriteCommand = RespCommand.BITOP_NOT;
internal const RespCommand LastDataCommand = RespCommand.EVALSHA;
/// <summary>
/// Last valid command (i.e. RespCommand with the largest value excluding INVALID).
/// </summary>
public static RespCommand LastValidCommand { get; } = Enum.GetValues<RespCommand>().Where(cmd => cmd != RespCommand.INVALID).Max();
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsReadOnly(this RespCommand cmd)
=> cmd <= LastReadCommand;
public static bool IsDataCommand(this RespCommand cmd)
{
return cmd switch
{
// TODO: validate if these cases need to be excluded
RespCommand.MIGRATE => false,
RespCommand.DBSIZE => false,
RespCommand.MEMORY_USAGE => false,
RespCommand.FLUSHDB => false,
RespCommand.FLUSHALL => false,
RespCommand.KEYS => false,
RespCommand.SCAN => false,
_ => cmd >= FirstReadCommand && cmd <= LastDataCommand
};
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsWriteOnly(this RespCommand cmd)
{
// If cmd < RespCommand.Append - underflows, setting high bits
var test = (uint)((int)cmd - (int)FirstWriteCommand);
// Force to be branchless for same reasons as OneIfRead
return test <= (LastWriteCommand - FirstWriteCommand);
}
/// <summary>
/// Returns 1 if <paramref name="cmd"/> is a write command.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong OneIfWrite(this RespCommand cmd)
{
var inRange = cmd.IsWriteOnly();
return Unsafe.As<bool, byte>(ref inRange);
}
/// <summary>
/// Returns 1 if <paramref name="cmd"/> is a read command.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong OneIfRead(this RespCommand cmd)
{
// Force this to be branchless (as predictability is poor)
// and we're in the hot path
var inRange = cmd.IsReadOnly();
return Unsafe.As<bool, byte>(ref inRange);
}
/// <summary>
/// Returns true if <paramref name="cmd"/> can be run even if the user is not authenticated.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsNoAuth(this RespCommand cmd)
{
// If cmd < RespCommand.Auth - underflows, setting high bits
uint test = (uint)((int)cmd - (int)RespCommand.AUTH);
bool inRange = test <= (RespCommand.QUIT - RespCommand.AUTH);
return inRange;
}
/// <summary>
/// Returns true if <paramref name="cmd"/> can is a cluster subcommand.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsClusterSubCommand(this RespCommand cmd)
{
// If cmd < RespCommand.CLUSTER_ADDSLOTS - underflows, setting high bits
uint test = (uint)((int)cmd - (int)RespCommand.CLUSTER_ADDSLOTS);
bool inRange = test <= (RespCommand.CLUSTER_SLOTSTATE - RespCommand.CLUSTER_ADDSLOTS);
return inRange;
}
}
/// <summary>
/// RESP command options enum
/// </summary>
enum RespCommandOption : byte
{
EX, NX, XX, GET, PX, EXAT, PXAT, PERSIST, GT, LT
}
/// <summary>
/// Server session for RESP protocol - command definitions and fast parsing
/// </summary>
internal sealed unsafe partial class RespServerSession : ServerSessionBase
{
/// <summary>
/// Fast-parses command type for inline RESP commands, starting at the current read head in the receive buffer
/// and advances read head.
/// </summary>
/// <param name="count">Outputs the number of arguments stored with the command.</param>
/// <returns>RespCommand that was parsed or RespCommand.NONE, if no command was matched in this pass.</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private RespCommand FastParseInlineCommand(out int count)
{
byte* ptr = recvBufferPtr + readHead;
count = 0;
if (bytesRead - readHead >= 6)
{
if ((*(ushort*)(ptr + 4) == MemoryMarshal.Read<ushort>("\r\n"u8)))
{
// Optimistically increase read head
readHead += 6;
if ((*(uint*)ptr) == MemoryMarshal.Read<uint>("PING"u8))
{
return RespCommand.PING;
}
if ((*(uint*)ptr) == MemoryMarshal.Read<uint>("QUIT"u8))
{
return RespCommand.QUIT;
}
// Decrease read head, if no match was found
readHead -= 6;
}
}
return RespCommand.NONE;
}
/// <summary>
/// Fast-parses for command type, starting at the current read head in the receive buffer
/// and advances the read head to the position after the parsed command.
/// </summary>
/// <param name="count">Outputs the number of arguments stored with the command</param>
/// <returns>RespCommand that was parsed or RespCommand.NONE, if no command was matched in this pass.</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private RespCommand FastParseCommand(out int count)
{
var ptr = recvBufferPtr + readHead;
var remainingBytes = bytesRead - readHead;
// Check if the package starts with "*_\r\n$_\r\n" (_ = masked out),
// i.e. an array with a single-digit length and single-digit first string length.
if ((remainingBytes >= 8) && (*(ulong*)ptr & 0xFFFF00FFFFFF00FF) == MemoryMarshal.Read<ulong>("*\0\r\n$\0\r\n"u8))
{
// Extract total element count from the array header.
// NOTE: Subtracting one to account for first token being parsed.
count = ptr[1] - '1';
Debug.Assert(count is >= 0 and < 9);
// Extract length of the first string header
var length = ptr[5] - '0';
Debug.Assert(length is > 0 and <= 9);
var oldReadHead = readHead;
// Ensure that the complete command string is contained in the package. Otherwise exit early.
// Include 10 bytes to account for array and command string headers, and terminator
// 10 bytes = "*_\r\n$_\r\n" (8 bytes) + "\r\n" (2 bytes) at end of command name
if (remainingBytes >= length + 10)
{
// Optimistically advance read head to the end of the command name
readHead += length + 10;
// Last 8 byte word of the command name, for quick comparison
var lastWord = *(ulong*)(ptr + length + 2);
//
// Fast path for common commands with fixed numbers of arguments
//
// Only check against commands with the correct count and length.
return ((count << 4) | length) switch
{
// Commands without arguments
4 when lastWord == MemoryMarshal.Read<ulong>("\r\nPING\r\n"u8) => RespCommand.PING,
4 when lastWord == MemoryMarshal.Read<ulong>("\r\nEXEC\r\n"u8) => RespCommand.EXEC,
5 when lastWord == MemoryMarshal.Read<ulong>("\nMULTI\r\n"u8) => RespCommand.MULTI,
6 when lastWord == MemoryMarshal.Read<ulong>("ASKING\r\n"u8) => RespCommand.ASKING,
7 when lastWord == MemoryMarshal.Read<ulong>("ISCARD\r\n"u8) && ptr[8] == 'D' => RespCommand.DISCARD,
7 when lastWord == MemoryMarshal.Read<ulong>("NWATCH\r\n"u8) && ptr[8] == 'U' => RespCommand.UNWATCH,
8 when lastWord == MemoryMarshal.Read<ulong>("ADONLY\r\n"u8) && *(ushort*)(ptr + 8) == MemoryMarshal.Read<ushort>("RE"u8) => RespCommand.READONLY,
9 when lastWord == MemoryMarshal.Read<ulong>("DWRITE\r\n"u8) && *(uint*)(ptr + 8) == MemoryMarshal.Read<uint>("READ"u8) => RespCommand.READWRITE,
// Commands with fixed number of arguments
(1 << 4) | 3 when lastWord == MemoryMarshal.Read<ulong>("3\r\nGET\r\n"u8) => RespCommand.GET,
(1 << 4) | 3 when lastWord == MemoryMarshal.Read<ulong>("3\r\nDEL\r\n"u8) => RespCommand.DEL,
(1 << 4) | 3 when lastWord == MemoryMarshal.Read<ulong>("3\r\nTTL\r\n"u8) => RespCommand.TTL,
(1 << 4) | 4 when lastWord == MemoryMarshal.Read<ulong>("\r\nDUMP\r\n"u8) => RespCommand.DUMP,
(1 << 4) | 4 when lastWord == MemoryMarshal.Read<ulong>("\r\nINCR\r\n"u8) => RespCommand.INCR,
(1 << 4) | 4 when lastWord == MemoryMarshal.Read<ulong>("\r\nPTTL\r\n"u8) => RespCommand.PTTL,
(1 << 4) | 4 when lastWord == MemoryMarshal.Read<ulong>("\r\nDECR\r\n"u8) => RespCommand.DECR,
(1 << 4) | 4 when lastWord == MemoryMarshal.Read<ulong>("EXISTS\r\n"u8) => RespCommand.EXISTS,
(1 << 4) | 6 when lastWord == MemoryMarshal.Read<ulong>("GETDEL\r\n"u8) => RespCommand.GETDEL,
(1 << 4) | 7 when lastWord == MemoryMarshal.Read<ulong>("ERSIST\r\n"u8) && ptr[8] == 'P' => RespCommand.PERSIST,
(1 << 4) | 7 when lastWord == MemoryMarshal.Read<ulong>("PFCOUNT\r\n"u8) && ptr[8] == 'P' => RespCommand.PFCOUNT,
(2 << 4) | 3 when lastWord == MemoryMarshal.Read<ulong>("3\r\nSET\r\n"u8) => RespCommand.SET,
(2 << 4) | 5 when lastWord == MemoryMarshal.Read<ulong>("\nPFADD\r\n"u8) => RespCommand.PFADD,
(2 << 4) | 6 when lastWord == MemoryMarshal.Read<ulong>("INCRBY\r\n"u8) => RespCommand.INCRBY,
(2 << 4) | 6 when lastWord == MemoryMarshal.Read<ulong>("DECRBY\r\n"u8) => RespCommand.DECRBY,
(2 << 4) | 6 when lastWord == MemoryMarshal.Read<ulong>("GETBIT\r\n"u8) => RespCommand.GETBIT,
(2 << 4) | 6 when lastWord == MemoryMarshal.Read<ulong>("APPEND\r\n"u8) => RespCommand.APPEND,
(2 << 4) | 6 when lastWord == MemoryMarshal.Read<ulong>("GETSET\r\n"u8) => RespCommand.GETSET,
(2 << 4) | 7 when lastWord == MemoryMarshal.Read<ulong>("UBLISH\r\n"u8) && ptr[8] == 'P' => RespCommand.PUBLISH,
(2 << 4) | 7 when lastWord == MemoryMarshal.Read<ulong>("FMERGE\r\n"u8) && ptr[8] == 'P' => RespCommand.PFMERGE,
(2 << 4) | 8 when lastWord == MemoryMarshal.Read<ulong>("UBLISH\r\n"u8) && *(ushort*)(ptr + 8) == MemoryMarshal.Read<ushort>("SP"u8) => RespCommand.SPUBLISH,
(2 << 4) | 5 when lastWord == MemoryMarshal.Read<ulong>("\nSETNX\r\n"u8) => RespCommand.SETNX,
(3 << 4) | 5 when lastWord == MemoryMarshal.Read<ulong>("\nSETEX\r\n"u8) => RespCommand.SETEX,
(3 << 4) | 6 when lastWord == MemoryMarshal.Read<ulong>("PSETEX\r\n"u8) => RespCommand.PSETEX,
(3 << 4) | 6 when lastWord == MemoryMarshal.Read<ulong>("SETBIT\r\n"u8) => RespCommand.SETBIT,
(3 << 4) | 6 when lastWord == MemoryMarshal.Read<ulong>("SUBSTR\r\n"u8) => RespCommand.SUBSTR,
(3 << 4) | 7 when lastWord == MemoryMarshal.Read<ulong>("ESTORE\r\n"u8) && ptr[8] == 'R' => RespCommand.RESTORE,
(3 << 4) | 8 when lastWord == MemoryMarshal.Read<ulong>("TRANGE\r\n"u8) && *(ushort*)(ptr + 8) == MemoryMarshal.Read<ushort>("SE"u8) => RespCommand.SETRANGE,
(3 << 4) | 8 when lastWord == MemoryMarshal.Read<ulong>("TRANGE\r\n"u8) && *(ushort*)(ptr + 8) == MemoryMarshal.Read<ushort>("GE"u8) => RespCommand.GETRANGE,
_ => ((length << 4) | count) switch
{
// Commands with dynamic number of arguments
>= ((6 << 4) | 2) and <= ((6 << 4) | 3) when lastWord == MemoryMarshal.Read<ulong>("RENAME\r\n"u8) => RespCommand.RENAME,
>= ((8 << 4) | 2) and <= ((8 << 4) | 3) when lastWord == MemoryMarshal.Read<ulong>("NAMENX\r\n"u8) && *(ushort*)(ptr + 8) == MemoryMarshal.Read<ushort>("RE"u8) => RespCommand.RENAMENX,
>= ((3 << 4) | 3) and <= ((3 << 4) | 7) when lastWord == MemoryMarshal.Read<ulong>("3\r\nSET\r\n"u8) => RespCommand.SETEXNX,
>= ((5 << 4) | 1) and <= ((5 << 4) | 3) when lastWord == MemoryMarshal.Read<ulong>("\nGETEX\r\n"u8) => RespCommand.GETEX,
>= ((6 << 4) | 0) and <= ((6 << 4) | 9) when lastWord == MemoryMarshal.Read<ulong>("RUNTXP\r\n"u8) => RespCommand.RUNTXP,
>= ((6 << 4) | 2) and <= ((6 << 4) | 3) when lastWord == MemoryMarshal.Read<ulong>("EXPIRE\r\n"u8) => RespCommand.EXPIRE,
>= ((6 << 4) | 2) and <= ((6 << 4) | 5) when lastWord == MemoryMarshal.Read<ulong>("BITPOS\r\n"u8) => RespCommand.BITPOS,
>= ((7 << 4) | 2) and <= ((7 << 4) | 3) when lastWord == MemoryMarshal.Read<ulong>("EXPIRE\r\n"u8) && ptr[8] == 'P' => RespCommand.PEXPIRE,
>= ((8 << 4) | 1) and <= ((8 << 4) | 4) when lastWord == MemoryMarshal.Read<ulong>("TCOUNT\r\n"u8) && *(ushort*)(ptr + 8) == MemoryMarshal.Read<ushort>("BI"u8) => RespCommand.BITCOUNT,
_ => MatchedNone(this, oldReadHead)
}
};
[MethodImpl(MethodImplOptions.AggressiveInlining)]
static RespCommand MatchedNone(RespServerSession session, int oldReadHead)
{
// Backup the read head, if we didn't find a command and need to continue in the more expensive parsing loop
session.readHead = oldReadHead;
return RespCommand.NONE;
}
}
}
else
{
return FastParseInlineCommand(out count);
}
// Couldn't find a matching command in this pass
count = -1;
return RespCommand.NONE;
}
/// <summary>
/// Fast parsing function for common command names.
/// Parses the receive buffer starting from the current read head and advances it to the end of
/// the parsed command/subcommand name.
/// </summary>
/// <param name="count">Reference to the number of remaining tokens in the packet. Will be reduced to number of command arguments.</param>
/// <returns>The parsed command name.</returns>
private RespCommand FastParseArrayCommand(ref int count, ref ReadOnlySpan<byte> specificErrorMessage)
{
// Bytes remaining in the read buffer
int remainingBytes = bytesRead - readHead;
// The current read head to continue reading from
byte* ptr = recvBufferPtr + readHead;
//
// Fast-path parsing by (1) command string length, (2) First character of command name (optional) and (3) priority (manual order)
//
// NOTE: A valid RESP string is at a minimum 7 characters long "$_\r\n_\r\n"
if (remainingBytes >= 7)
{
var oldReadHead = readHead;
// Check if this is a string with a single-digit length ("$_\r\n" -> _ omitted)
if ((*(uint*)ptr & 0xFFFF00FF) == MemoryMarshal.Read<uint>("$\0\r\n"u8))
{
// Extract length from string header
var length = ptr[1] - '0';
Debug.Assert(length is > 0 and <= 9);
// Ensure that the complete command string is contained in the package. Otherwise exit early.
// Include 6 bytes to account for command string header and name terminator.
// 6 bytes = "$_\r\n" (4 bytes) + "\r\n" (2 bytes) at end of command name
if (remainingBytes >= length + 6)
{
// Optimistically increase read head and decrease the number of remaining elements
readHead += length + 6;
count -= 1;
switch (length)
{
case 3:
if (*(ulong*)(ptr + 1) == MemoryMarshal.Read<ulong>("3\r\nDEL\r\n"u8))
{
return RespCommand.DEL;
}
else if (*(ulong*)(ptr + 1) == MemoryMarshal.Read<ulong>("3\r\nLCS\r\n"u8))
{
return RespCommand.LCS;
}
break;
case 4:
switch ((ushort)ptr[4])
{
case 'E':
if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nEVAL\r\n"u8))
{
return RespCommand.EVAL;
}
break;
case 'H':
if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nHSET\r\n"u8))
{
return RespCommand.HSET;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nHGET\r\n"u8))
{
return RespCommand.HGET;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nHDEL\r\n"u8))
{
return RespCommand.HDEL;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nHLEN\r\n"u8))
{
return RespCommand.HLEN;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nHTTL\r\n"u8))
{
return RespCommand.HTTL;
}
break;
case 'K':
if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nKEYS\r\n"u8))
{
return RespCommand.KEYS;
}
break;
case 'L':
if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nLPOP\r\n"u8))
{
return RespCommand.LPOP;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nLLEN\r\n"u8))
{
return RespCommand.LLEN;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nLREM\r\n"u8))
{
return RespCommand.LREM;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nLSET\r\n"u8))
{
return RespCommand.LSET;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nLPOS\r\n"u8))
{
return RespCommand.LPOS;
}
break;
case 'M':
if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nMGET\r\n"u8))
{
return RespCommand.MGET;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nMSET\r\n"u8))
{
return RespCommand.MSET;
}
break;
case 'R':
if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nRPOP\r\n"u8))
{
return RespCommand.RPOP;
}
break;
case 'S':
if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nSCAN\r\n"u8))
{
return RespCommand.SCAN;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nSADD\r\n"u8))
{
return RespCommand.SADD;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nSREM\r\n"u8))
{
return RespCommand.SREM;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nSPOP\r\n"u8))
{
return RespCommand.SPOP;
}
break;
case 'T':
if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nTYPE\r\n"u8))
{
return RespCommand.TYPE;
}
break;
case 'Z':
if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nZADD\r\n"u8))
{
return RespCommand.ZADD;
}
else if (*(ulong*)(ptr + 2) == MemoryMarshal.Read<ulong>("\r\nZREM\r\n"u8))
{
return RespCommand.ZREM;
}
break;
}
break;
case 5:
switch ((ushort)ptr[4])
{
case 'B':
if (*(ulong*)(ptr + 3) == MemoryMarshal.Read<ulong>("\nBITOP\r\n"u8))
{
// Check for matching bit-operation
if (remainingBytes > length + 6 + 8)
{
// TODO: AND|OR|XOR|NOT may not correctly handle mixed cases?
// 2-character operations
if (*(uint*)(ptr + 11) == MemoryMarshal.Read<uint>("$2\r\n"u8))
{
if (*(ulong*)(ptr + 11) == MemoryMarshal.Read<ulong>("$2\r\nOR\r\n"u8) || *(ulong*)(ptr + 11) == MemoryMarshal.Read<ulong>("$2\r\nor\r\n"u8))
{
readHead += 8;
count -= 1;
return RespCommand.BITOP_OR;
}
}
// 3-character operations
else if (remainingBytes > length + 6 + 9)
{
if (*(uint*)(ptr + 11) == MemoryMarshal.Read<uint>("$3\r\n"u8))
{
// Optimistically adjust read head and count
readHead += 9;
count -= 1;
if (*(ulong*)(ptr + 12) == MemoryMarshal.Read<ulong>("3\r\nAND\r\n"u8) || *(ulong*)(ptr + 12) == MemoryMarshal.Read<ulong>("3\r\nand\r\n"u8))
{
return RespCommand.BITOP_AND;
}
else if (*(ulong*)(ptr + 12) == MemoryMarshal.Read<ulong>("3\r\nXOR\r\n"u8) || *(ulong*)(ptr + 12) == MemoryMarshal.Read<ulong>("3\r\nxor\r\n"u8))
{
return RespCommand.BITOP_XOR;
}
else if (*(ulong*)(ptr + 12) == MemoryMarshal.Read<ulong>("3\r\nNOT\r\n"u8) || *(ulong*)(ptr + 12) == MemoryMarshal.Read<ulong>("3\r\nnot\r\n"u8))
{
return RespCommand.BITOP_NOT;
}
// Reset read head and count if we didn't match operator.
readHead -= 9;
count += 1;
}
}
// Although we recognize BITOP, the pseudo-subcommand isn't recognized so fail early
specificErrorMessage = CmdStrings.RESP_SYNTAX_ERROR;
return RespCommand.NONE;