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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/stdx/mutex.h"
#include "mongo/util/assert_util.h"
namespace mongo {
/**
* RAII object that unlocks a unique_lock type on construction, and relocks it on destruction. The
* unique_lock must be locked when it is given to ScopedUnlock.
*/
template <typename T>
class ScopedUnlock {
public:
/**
* Construct a new Scoped Unlock object.
* Unique_locks passed into this constructor must be locked, or an invariant failure will be
* thrown.
*/
explicit ScopedUnlock(stdx::unique_lock<T>& lock) : _lock(lock) {
invariant(_lock.owns_lock(), "Locks in ScopedUnlock must be locked on initialization.");
_lock.unlock();
}
~ScopedUnlock() {
if (!_dismissed) {
_lock.lock();
}
}
ScopedUnlock(const ScopedUnlock&) = delete;
ScopedUnlock(ScopedUnlock&&) = delete;
ScopedUnlock& operator=(const ScopedUnlock&) = delete;
ScopedUnlock& operator=(ScopedUnlock&&) = delete;
/** A dismissed ScopedUnlock does not lock on destruction. */
void dismiss() noexcept {
_dismissed = true;
}
private:
stdx::unique_lock<T>& _lock;
bool _dismissed = false;
};
} // namespace mongo
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