wire

const (
	// OpCodeReply is used for the initial handshake with old clients.
	// It is not used otherwise and is deprecated.
	OpCodeReply = OpCode(1) // OP_REPLY

	// OpCodeUpdate is deprecated.
	OpCodeUpdate = OpCode(2001) // OP_UPDATE

	// OpCodeInsert is deprecated and unused.
	OpCodeInsert = OpCode(2002) // OP_INSERT

	// OpCodeGetByOID is deprecated and unused.
	OpCodeGetByOID = OpCode(2003) // OP_GET_BY_OID

	// OpCodeQuery is used for the initial handshake with old clients.
	// It is not used otherwise and is deprecated.
	OpCodeQuery = OpCode(2004) // OP_QUERY

	// OpCodeGetMore is deprecated and unused.
	OpCodeGetMore = OpCode(2005) // OP_GET_MORE

	// OpCodeDelete is deprecated and unused.
	OpCodeDelete = OpCode(2006) // OP_DELETE

	// OpCodeKillCursors is deprecated and unused.
	OpCodeKillCursors = OpCode(2007) // OP_KILL_CURSORS

	// OpCodeCompressed is not implemented yet.
	OpCodeCompressed = OpCode(2012) // OP_COMPRESSED

	// OpCodeMsg is the main operation for client-server communication.
	OpCodeMsg = OpCode(2013) // OP_MSG
)

const (
	// MsgHeaderLen is an expected len of the header.
	MsgHeaderLen = 16

	// MaxMsgLen is the maximum message length.
	MaxMsgLen = 48000000
)

const (
	// OpMsgChecksumPresent indicates that there is a CRC-32C checksum in a message.
	OpMsgChecksumPresent = OpMsgFlagBit(1 << 0) // checksumPresent

	// OpMsgMoreToCome indicates that there is another message coming, no need to do anything for it.
	OpMsgMoreToCome = OpMsgFlagBit(1 << 1) // moreToCome

	// OpMsgExhaustAllowed indicates that client can handle multiple replies.
	OpMsgExhaustAllowed = OpMsgFlagBit(1 << 16) // exhaustAllowed
)

const (
	// OpQueryTailableCursor indicates that the cursor will not be closed.
	OpQueryTailableCursor = OpQueryFlagBit(1 << 1) // TailableCursor

	// OpQuerySlaveOk indicates that query can run on a replica slave.
	OpQuerySlaveOk = OpQueryFlagBit(1 << 2) // SlaveOk

	// OpQueryOplogReplay is deprecated.
	OpQueryOplogReplay = OpQueryFlagBit(1 << 3) // OplogReplay

	// OpQueryNoCursorTimeout disables cursor timeouts.
	OpQueryNoCursorTimeout = OpQueryFlagBit(1 << 4) // NoCursorTimeout

	// OpQueryAwaitData together with OpQueryTailableCursor, waits for data instead of returning it.
	OpQueryAwaitData = OpQueryFlagBit(1 << 5) // AwaitData

	// OpQueryExhaust indicates that server can divide data into multiple streams and expect that client can handle it.
	OpQueryExhaust = OpQueryFlagBit(1 << 6) // Exhaust

	// OpQueryPartial ignore error and give partial results.
	OpQueryPartial = OpQueryFlagBit(1 << 7) // Partial
)

const (
	// OpReplyCursorNotFound indicates that the cursor is no longer exist at the server.
	OpReplyCursorNotFound = OpReplyFlagBit(1 << 0) // CursorNotFound

	// OpReplyQueryFailure reports query has failed.
	OpReplyQueryFailure = OpReplyFlagBit(1 << 1) // QueryFailure

	// OpReplyShardConfigStale indicates that shard config is outdated.
	OpReplyShardConfigStale = OpReplyFlagBit(1 << 2) // ShardConfigStale

	// OpReplyAwaitCapable indicates server supports AwaitData Query option.
	OpReplyAwaitCapable = OpReplyFlagBit(1 << 3) // AwaitCapable
)