1 
2 /**
3  *    Copyright (C) 2018-present MongoDB, Inc.
4  *
5  *    This program is free software: you can redistribute it and/or modify
6  *    it under the terms of the Server Side Public License, version 1,
7  *    as published by MongoDB, Inc.
8  *
9  *    This program is distributed in the hope that it will be useful,
10  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
11  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  *    Server Side Public License for more details.
13  *
14  *    You should have received a copy of the Server Side Public License
15  *    along with this program. If not, see
16  *    <http://www.mongodb.com/licensing/server-side-public-license>.
17  *
18  *    As a special exception, the copyright holders give permission to link the
19  *    code of portions of this program with the OpenSSL library under certain
20  *    conditions as described in each individual source file and distribute
21  *    linked combinations including the program with the OpenSSL library. You
22  *    must comply with the Server Side Public License in all respects for
23  *    all of the code used other than as permitted herein. If you modify file(s)
24  *    with this exception, you may extend this exception to your version of the
25  *    file(s), but you are not obligated to do so. If you do not wish to do so,
26  *    delete this exception statement from your version. If you delete this
27  *    exception statement from all source files in the program, then also delete
28  *    it in the license file.
29  */
30 
31 #pragma once
32 
33 #include <map>
34 #include <string>
35 
36 #include "mongo/base/disallow_copying.h"
37 
38 namespace mongo {
39 
40 struct ChunkVersion;
41 class Client;
42 class ServiceContext;
43 
44 /**
45  * There is one instance of these per each connection from mongos. Holds version state for each
46  * namespace.
47  */
48 class ShardedConnectionInfo {
49     MONGO_DISALLOW_COPYING(ShardedConnectionInfo);
50 
51 public:
52     ShardedConnectionInfo();
53     ~ShardedConnectionInfo();
54 
55     static ShardedConnectionInfo* get(Client* client, bool create);
56 
57     /**
58      * Returns the shard version associated with the specified namespace on this connection. If no
59      * version is associated with the namespace returns ChunkVersion::UNSHARDED.
60      */
61     ChunkVersion getVersion(const std::string& ns) const;
62 
63     /**
64      * Assigns a new version on the connection to the specified namespace.
65      */
66     void setVersion(const std::string& ns, const ChunkVersion& version);
67 
68     static void reset(Client* client);
69     static void addHook(ServiceContext* service);
70 
71 private:
72     typedef std::map<std::string, ChunkVersion> NSVersionMap;
73 
74     // Map from a namespace string to the chunk version with which this connection has been
75     // initialized for the specified namespace
76     NSVersionMap _versions;
77 
78     // If this is true, then chunk versions aren't checked, and all operations are allowed
79     bool _forceVersionOk;
80 };
81 
82 
83 }  // namespace mongo
84