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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.
*/
#include "mongo/platform/basic.h"
#include "mongo/rpc/command_request_builder.h"
#include "mongo/client/read_preference.h"
#include "mongo/db/command_generic_argument.h"
#include "mongo/db/commands.h"
#include "mongo/util/assert_util.h"
namespace mongo {
namespace rpc {
namespace {
// OP_COMMAND put some generic arguments in the metadata and some in the body.
bool fieldGoesInMetadata(StringData commandName, StringData field) {
if (!isGenericArgument(field))
return false; // All non-generic arguments go to the body.
// For some reason this goes in the body only for a single command...
if (field == "$replData")
return commandName != "replSetUpdatePosition";
// These generic arguments went in the body.
return !(field == "maxTimeMS" || field == "readConcern" || field == "writeConcern" ||
field == "shardVersion");
}
} // namespace
Message opCommandRequestFromOpMsgRequest(const OpMsgRequest& request) {
const auto commandName = request.getCommandName();
BufBuilder builder;
builder.skip(mongo::MsgData::MsgDataHeaderSize); // Leave room for message header.
builder.appendStr(request.getDatabase());
builder.appendStr(commandName);
// OP_COMMAND is only used when communicating with 3.4 nodes and they serialize their metadata
// fields differently. In addition to field-level differences, some generic arguments are pulled
// out to a metadata object, separate from the body. We do all down-conversion here so that the
// rest of the code only has to deal with the current format.
BSONObjBuilder metadataBuilder; // Will be appended to the message after we finish the body.
{
BSONObjBuilder bodyBuilder(builder);
for (auto elem : request.body) {
const auto fieldName = elem.fieldNameStringData();
if (fieldName == "$configServerState") {
metadataBuilder.appendAs(elem, "configsvr");
} else if (fieldName == "$readPreference") {
BSONObjBuilder ssmBuilder(metadataBuilder.subobjStart("$ssm"));
ssmBuilder.append(elem);
ssmBuilder.append("$secondaryOk",
uassertStatusOK(ReadPreferenceSetting::fromInnerBSON(elem))
.canRunOnSecondary());
} else if (fieldName == "$db") {
// skip
} else if (fieldGoesInMetadata(commandName, fieldName)) {
metadataBuilder.append(elem);
} else {
bodyBuilder.append(elem);
}
}
for (auto&& seq : request.sequences) {
invariant(seq.name.find('.') == std::string::npos); // Only support top-level for now.
dassert(!bodyBuilder.asTempObj().hasField(seq.name));
bodyBuilder.append(seq.name, seq.objs);
}
}
metadataBuilder.obj().appendSelfToBufBuilder(builder);
MsgData::View msg = builder.buf();
msg.setLen(builder.len());
msg.setOperation(dbCommand);
return Message(builder.release());
}
} // namespace rpc
} // namespace mongo
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