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/**
* Copyright (C) 2016 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/db/s/metadata_manager.h"
#include "mongo/db/s/collection_metadata.h"
#include "mongo/stdx/memory.h"
namespace mongo {
MetadataManager::MetadataManager() = default;
ScopedCollectionMetadata MetadataManager::getActiveMetadata() {
invariant(_activeMetadataTracker);
return ScopedCollectionMetadata(this, _activeMetadataTracker.get());
}
void MetadataManager::setActiveMetadata(std::unique_ptr<CollectionMetadata> newMetadata) {
if (_activeMetadataTracker && _activeMetadataTracker->usageCounter > 0) {
_metadataInUse.push_front(std::move(_activeMetadataTracker));
}
_activeMetadataTracker = stdx::make_unique<CollectionMetadataTracker>(std::move(newMetadata));
}
void MetadataManager::_removeMetadata(CollectionMetadataTracker* metadataTracker) {
invariant(metadataTracker->usageCounter == 0);
auto i = _metadataInUse.begin();
auto e = _metadataInUse.end();
while (i != e) {
if (metadataTracker == i->get()) {
_metadataInUse.erase(i);
return;
}
i++;
}
}
MetadataManager::CollectionMetadataTracker::CollectionMetadataTracker(
std::unique_ptr<CollectionMetadata> m)
: metadata(std::move(m)), usageCounter(0){};
ScopedCollectionMetadata::ScopedCollectionMetadata(
MetadataManager* manager, MetadataManager::CollectionMetadataTracker* tracker)
: _manager(manager), _tracker(tracker) {
_tracker->usageCounter++;
}
ScopedCollectionMetadata::~ScopedCollectionMetadata() {
invariant(_tracker->usageCounter > 0);
if (--_tracker->usageCounter == 0) {
_manager->_removeMetadata(_tracker);
}
}
CollectionMetadata* ScopedCollectionMetadata::operator->() {
return _tracker->metadata.get();
}
CollectionMetadata* ScopedCollectionMetadata::getMetadata() {
return _tracker->metadata.get();
}
ScopedCollectionMetadata::ScopedCollectionMetadata(ScopedCollectionMetadata&& other) {
*this = std::move(other);
}
ScopedCollectionMetadata& ScopedCollectionMetadata::operator=(ScopedCollectionMetadata&& other) {
if (this != &other) {
_manager = other._manager;
_tracker = other._tracker;
other._manager = nullptr;
other._tracker = nullptr;
}
return *this;
}
} // namespace mongo
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