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/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include <cstdint>
#include <string>
#include <type_traits>
#include "mongo/base/status_with.h"
#include "mongo/db/wire_version.h"
namespace mongo {
class BSONObj;
class OperationContext;
namespace rpc {
/**
* Bit flags representing support for a particular RPC protocol.
* This is just an internal representation, and is never transmitted over the wire. It should
* never be used for any other feature detection in favor of max/min wire version.
*
* A new protocol must be added as the highest order bit flag so that it is prioritized in
* negotiation.
*/
enum class Protocol : std::uint64_t {
/**
* The pre-3.2 OP_QUERY on db.$cmd protocol
*/
kOpQuery = 1 << 0,
/**
* The post-3.2 OP_COMMAND protocol.
*/
kOpCommandV1 = 1 << 1,
};
/**
* Bitfield representing a set of supported RPC protocols.
*/
using ProtocolSet = std::underlying_type<Protocol>::type;
/**
* This namespace contains predefined bitfields for common levels of protocol support.
*/
namespace supports {
const ProtocolSet kNone = ProtocolSet{0};
const ProtocolSet kOpQueryOnly = static_cast<ProtocolSet>(Protocol::kOpQuery);
const ProtocolSet kOpCommandOnly = static_cast<ProtocolSet>(Protocol::kOpCommandV1);
const ProtocolSet kAll = kOpQueryOnly | kOpCommandOnly;
} // namespace supports
/**
* Returns the protocol used to initiate the current operation.
*/
Protocol getOperationProtocol(OperationContext* txn);
/**
* Sets the protocol used to initiate the current operation.
*/
void setOperationProtocol(OperationContext* txn, Protocol protocol);
/**
* Returns the newest protocol supported by two parties.
*/
StatusWith<Protocol> negotiate(ProtocolSet fst, ProtocolSet snd);
/**
* Converts a ProtocolSet to a string. Currently only the predefined ProtocolSets in the
* 'supports' namespace are supported.
*
* This intentionally does not conform to the STL 'to_string' convention so that it will
* not conflict with the to_string overload for uint64_t.
*/
StatusWith<StringData> toString(ProtocolSet protocols);
/**
* Parses a ProtocolSet from a string. Currently only the predefined ProtocolSets in the
* 'supports' namespace are supported
*/
StatusWith<ProtocolSet> parseProtocolSet(StringData repr);
/**
* Validates client and server wire version. The server is returned from isMaster, and the client is
* from WireSpec.instance().
*/
Status validateWireVersion(const WireVersionInfo client, const WireVersionInfo server);
/**
* Struct to pass around information about protocol set and wire version.
*/
struct ProtocolSetAndWireVersionInfo {
ProtocolSet protocolSet;
WireVersionInfo version;
};
/**
* Determines the ProtocolSet of a remote server from an isMaster reply.
*/
StatusWith<ProtocolSetAndWireVersionInfo> parseProtocolSetFromIsMasterReply(
const BSONObj& isMasterReply);
/**
* Returns true if wire version supports OP_COMMAND in mongod (not mongos).
*/
bool supportsWireVersionForOpCommandInMongod(const WireVersionInfo version);
/**
* Computes supported protocols from wire versions.
*/
ProtocolSet computeProtocolSet(const WireVersionInfo version);
} // namespace rpc
} // namespace mongo
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