folly/folly/io/async/AsyncBase.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 <sys/types.h>

#include <atomic>
#include <cstdint>
#include <deque>
#include <functional>
#include <iosfwd>
#include <mutex>
#include <utility>
#include <vector>

#include <folly/Function.h>
#include <folly/Portability.h>
#include <folly/Range.h>
#include <folly/portability/SysUio.h>

namespace folly {
class AsyncIOOp;
class IoUringOp;
/**
 * An AsyncBaseOp represents a pending operation.  You may set a notification
 * callback or you may use this class's methods directly.
 *
 * The op must remain allocated until it is completed or canceled.
 */
class AsyncBaseOp { … };

std::ostream& operator<<(std::ostream& os, const AsyncBaseOp& op);
std::ostream& operator<<(std::ostream& os, AsyncBaseOp::State state);

/**
 * Generic C++ interface around Linux IO(io_submit, io_uring)
 */
class AsyncBase { … };

/**
 * Wrapper around AsyncBase that allows you to schedule more requests than
 * the AsyncBase's object capacity.  Other requests are queued and processed
 * in a FIFO order.
 */
class AsyncBaseQueue { … };

} // namespace folly