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Diffstat (limited to 'src/mongo/rpc/metadata.h')
| -rw-r--r-- | src/mongo/rpc/metadata.h | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/src/mongo/rpc/metadata.h b/src/mongo/rpc/metadata.h new file mode 100644 index 00000000000..183dedffc5d --- /dev/null +++ b/src/mongo/rpc/metadata.h @@ -0,0 +1,93 @@ +/** + * 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 <tuple> + +#include "mongo/base/status_with.h" + +namespace mongo { + class BSONObj; + +/** + * Utilities for converting metadata between the legacy OP_QUERY format and the new + * OP_COMMAND format. + * + * Metadata consists of information independent of any particular command such as: + * + * Request/Reply/Both | (legacy) OP_QUERY format | OP_COMMAND format + *__________________________________________________________________________________________________ + * Request | the slaveOk bit | $secondaryOk on metadata obj + * Request | $readPreference field of command | $readPreference on metadata obj + * Request | $impersonatedUsers on command obj| $impersonatedUsers on metadata obj + * Request | $impersonatedRoles on command obj| $impersonatedRoles on metadata obj + * Request | maxTimeMS on command obj | $maxTimeMS on metadata obj + * Reply | $gleStats field on command reply | $gleStats on metadata obj + * + * TODO: currently only $secondaryOk (request only) is handled. SERVER-18236 will cover the rest. + */ +namespace rpc { +namespace metadata { + + /** + * Returns an empty metadata object. + */ + BSONObj empty(); + + /** + * The field name for the secondaryOk metadata field. + */ + extern const char kSecondaryOk[]; + + /** + * A command object and a corresponding metadata object. + */ + using CommandAndMetadata = std::tuple<BSONObj, BSONObj>; + + /** + * A legacy command object and a corresponding query flags bitfield. The legacy command object + * may contain metadata fields, so it cannot safely be passed to a command's run method. + */ + using LegacyCommandAndFlags = std::tuple<BSONObj, int>; + + /** + * Given a legacy command object and a query flags bitfield, attempts to parse and remove + * the metadata from the command object and construct a corresponding metadata object. + */ + StatusWith<CommandAndMetadata> upconvertRequest(BSONObj legacyCmdObj, int queryFlags); + + /** + * Given a command object and a metadata object, attempts to construct a legacy command + * object and query flags bitfield augmented with the given metadata. + */ + StatusWith<LegacyCommandAndFlags> downconvertRequest(BSONObj cmdObj, BSONObj metadata); + +} // namespace metadata +} // namespace rpc +} // namespace mongo |