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/**
* 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/catalog/collection.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/query/query_planner_params.h"
namespace mongo {
/**
* Class which holds a set of pointers to multiple collections. This class distinguishes between
* a 'main collection' and 'secondary collections'. While the former represents the collection a
* given command is run against, the latter represents other collections that the execution
* engine may need to be made aware of.
*/
class MultiCollection final {
public:
MultiCollection() = default;
MultiCollection(boost::optional<AutoGetCollectionForReadCommandMaybeLockFree>& mainCollCtx,
std::vector<std::unique_ptr<AutoGetCollectionForReadCommandMaybeLockFree>>&
secondaryCollCtxes) {
if (mainCollCtx) {
_mainColl = &mainCollCtx->getCollection();
_mainCollName = mainCollCtx->getNss();
}
for (auto& secondaryColl : secondaryCollCtxes) {
if (*secondaryColl) {
// Even if 'secondaryColl' doesn't exist, we still want to include it. It is the
// responsibility of consumers of this class to verify that a collection exists
// before accessing it.
_secondaryColls.emplace(secondaryColl->getNss(), secondaryColl->getCollection());
}
}
}
explicit MultiCollection(const CollectionPtr* mainColl)
: _mainColl(mainColl), _secondaryColls({}) {}
explicit MultiCollection(const CollectionPtr& mainColl) : MultiCollection(&mainColl) {}
bool hasMainCollection() const {
return _mainColl->get();
}
const CollectionPtr& getMainCollection() const {
return *_mainColl;
}
const std::map<NamespaceString, const CollectionPtr&>& getSecondaryCollections() const {
return _secondaryColls;
}
void clear() {
_mainColl = &CollectionPtr::null;
_secondaryColls.clear();
}
private:
const CollectionPtr* _mainColl{&CollectionPtr::null};
boost::optional<NamespaceString> _mainCollName = boost::none;
// Map from namespace to a corresponding CollectionPtr.
std::map<NamespaceString, const CollectionPtr&> _secondaryColls{};
};
} // namespace mongo
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