1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
/**
* 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).transitional_ignore();
}
_state = State::kOutputDocs;
return *this;
}
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
|
