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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/legacy_reply_builder.h"
#include <iterator>
#include "mongo/db/dbmessage.h"
#include "mongo/db/jsobj.h"
#include "mongo/rpc/metadata.h"
#include "mongo/rpc/metadata/sharding_metadata.h"
#include "mongo/stdx/memory.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
namespace rpc {
LegacyReplyBuilder::LegacyReplyBuilder() : LegacyReplyBuilder(Message()) {}
LegacyReplyBuilder::LegacyReplyBuilder(Message&& message) : _message{std::move(message)} {
_builder.skip(sizeof(QueryResult::Value));
}
LegacyReplyBuilder::~LegacyReplyBuilder() {}
LegacyReplyBuilder& LegacyReplyBuilder::setCommandReply(Status nonOKStatus,
const BSONObj& extraErrorInfo) {
invariant(_state == State::kCommandReply);
if (nonOKStatus == ErrorCodes::SendStaleConfig) {
_staleConfigError = true;
// Need to use the special $err format for SendStaleConfig errors to be backwards
// compatible.
BSONObjBuilder err;
// $err must be the first field in object.
err.append("$err", nonOKStatus.reason());
err.append("code", nonOKStatus.code());
err.appendElements(extraErrorInfo);
setRawCommandReply(err.done());
} else {
// All other errors proceed through the normal path, which also handles state transitions.
ReplyBuilderInterface::setCommandReply(std::move(nonOKStatus), extraErrorInfo);
}
return *this;
}
LegacyReplyBuilder& LegacyReplyBuilder::setRawCommandReply(const BSONObj& commandReply) {
invariant(_state == State::kCommandReply);
commandReply.appendSelfToBufBuilder(_builder);
_state = State::kMetadata;
return *this;
}
BSONObjBuilder LegacyReplyBuilder::getInPlaceReplyBuilder(std::size_t reserveBytes) {
invariant(_state == State::kCommandReply);
// Eagerly allocate reserveBytes bytes.
_builder.reserveBytes(reserveBytes);
// Claim our reservation immediately so we can actually write data to it.
_builder.claimReservedBytes(reserveBytes);
_state = State::kMetadata;
return BSONObjBuilder(_builder);
}
LegacyReplyBuilder& LegacyReplyBuilder::setMetadata(const BSONObj& metadata) {
invariant(_state == State::kMetadata);
// HACK: the only thing we need to downconvert is ShardingMetadata, which can go at the end of
// the object. So we do that in place to avoid copying the command reply.
auto shardingMetadata = rpc::ShardingMetadata::readFromMetadata(metadata);
invariant(shardingMetadata.isOK() || shardingMetadata.getStatus() == ErrorCodes::NoSuchKey);
if (shardingMetadata.isOK()) {
// Write the sharding metadata in to the end of the object. The third parameter is needed
// because we already have skipped some bytes for the message header.
BSONObjBuilder resumedBuilder(
BSONObjBuilder::ResumeBuildingTag(), _builder, sizeof(QueryResult::Value));
shardingMetadata.getValue().writeToMetadata(&resumedBuilder);
}
_state = State::kOutputDocs;
return *this;
}
Status LegacyReplyBuilder::addOutputDocs(DocumentRange docs) {
invariant(_state == State::kOutputDocs);
// no op
return Status::OK();
}
Status LegacyReplyBuilder::addOutputDoc(const BSONObj& bson) {
invariant(_state == State::kOutputDocs);
// no op
return Status::OK();
}
Protocol LegacyReplyBuilder::getProtocol() const {
return rpc::Protocol::kOpQuery;
}
void LegacyReplyBuilder::reset() {
// If we are in State::kMetadata, we are already in the 'start' state, so by
// immediately returning, we save a heap allocation.
if (_state == State::kCommandReply) {
return;
}
_builder.reset();
_builder.skip(sizeof(QueryResult::Value));
_message.reset();
_state = State::kCommandReply;
_staleConfigError = false;
}
Message LegacyReplyBuilder::done() {
invariant(_state == State::kOutputDocs);
QueryResult::View qr = _builder.buf();
if (_staleConfigError) {
// For compatibility with legacy mongos, we need to set this result flag on SendStaleConfig
qr.setResultFlags(ResultFlag_ErrSet | ResultFlag_ShardConfigStale);
} else {
qr.setResultFlagsToOk();
}
qr.msgdata().setLen(_builder.len());
qr.msgdata().setOperation(opReply);
qr.setCursorId(0);
qr.setStartingFrom(0);
qr.setNReturned(1);
_message.setData(_builder.release());
_state = State::kDone;
return std::move(_message);
}
} // namespace rpc
} // namespace mongo
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