/**
 *    Copyright (C) 2021-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/concurrency/locker_noop.h"
#include "mongo/db/service_context.h"

namespace mongo {

/**
 * ServiceContext hook that ensures OperationContexts are created with a valid
 * Locker instance. Intended for use in tests that do not require a storage engine.
 */
class LockerNoopClientObserver : public ServiceContext::ClientObserver {
public:
    LockerNoopClientObserver() = default;
    ~LockerNoopClientObserver() = default;

    void onCreateClient(Client* client) final {}

    void onDestroyClient(Client* client) final {}

    void onCreateOperationContext(OperationContext* opCtx) override {
        opCtx->setLockState(std::make_unique<LockerNoop>());
    }

    void onDestroyOperationContext(OperationContext* opCtx) final {}
};

/**
 * Unlike LockerNoopClientObserver, this ClientObserver will not overwrite any existing Lockers on
 * the OperationContext.
 *
 * This class is suitable for test fixtures that may be used in executables with LockerImpl service
 * hooks installed.
 */
class LockerNoopClientObserverWithReplacementPolicy : public LockerNoopClientObserver {
public:
    LockerNoopClientObserverWithReplacementPolicy() = default;
    ~LockerNoopClientObserverWithReplacementPolicy() = default;

    void onCreateOperationContext(OperationContext* opCtx) final {
        if (opCtx->lockState()) {
            return;
        }
        LockerNoopClientObserver::onCreateOperationContext(opCtx);
    }
};

}  // namespace mongo