folly/folly/io/async/VirtualEventBase.h

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <future>

#include <folly/Executor.h>
#include <folly/Function.h>
#include <folly/Synchronized.h>
#include <folly/executors/SequencedExecutor.h>
#include <folly/io/async/EventBase.h>
#include <folly/synchronization/Baton.h>

namespace folly {

/**
 * VirtualEventBase implements a light-weight view onto existing EventBase.
 *
 * Multiple VirtualEventBases can be backed by a single EventBase. Similarly
 * to EventBase, VirtualEventBase implements KeepAlive functionality,
 * which allows callbacks holding KeepAlive token to keep EventBase looping
 * until they are complete.
 *
 * VirtualEventBase destructor blocks until all its KeepAliveTokens are released
 * and all tasks scheduled through it are complete. EventBase destructor also
 * blocks until all VirtualEventBases backed by it are released.
 */
class VirtualEventBase : public folly::TimeoutManager,
                         public folly::SequencedExecutor { … };
} // namespace folly