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
|
/**
* Copyright (C) 2022-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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 "mongo/db/clientcursor.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/pipeline/external_data_source_option_gen.h"
namespace mongo {
/**
* This class makes sure that virtual collections that are created for external data sources are
* dropped when it's destroyed.
*/
class ExternalDataSourceScopeGuard {
public:
// Makes ExternalDataSourceScopeGuard a decoration of ClientCursor.
static const ClientCursor::Decoration<std::shared_ptr<ExternalDataSourceScopeGuard>> get;
// Updates the operation context of decorated ExternalDataSourceScopeGuard object of 'cursor'
// so that it can drop virtual collections in the new 'opCtx'.
static void updateOperationContext(const ClientCursor* cursor, OperationContext* opCtx) {
if (auto self = get(cursor); self) {
self->_opCtx = opCtx;
}
}
ExternalDataSourceScopeGuard() : _opCtx(nullptr), _toBeDroppedVirtualCollections() {}
ExternalDataSourceScopeGuard(
OperationContext* opCtx,
const std::vector<std::pair<NamespaceString, std::vector<ExternalDataSourceInfo>>>&
usedExternalDataSources);
// It does not make sense to support copy ctor because this object must drop created virtual
// collections.
ExternalDataSourceScopeGuard(const ExternalDataSourceScopeGuard&) = delete;
ExternalDataSourceScopeGuard(ExternalDataSourceScopeGuard&& other) noexcept
: _opCtx(other._opCtx),
_toBeDroppedVirtualCollections(std::move(other._toBeDroppedVirtualCollections)) {
// Ownership of created virtual collections are moved to this object and the other object
// must not try to drop them any more.
other._opCtx = nullptr;
}
~ExternalDataSourceScopeGuard() {
dropVirtualCollections();
}
private:
void dropVirtualCollections() noexcept;
OperationContext* _opCtx;
std::vector<NamespaceString> _toBeDroppedVirtualCollections;
};
} // namespace mongo
|
