folly/folly/io/async/fdsock/AsyncFdSocket.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 <folly/io/async/AsyncSocket.h>
#include <folly/io/async/fdsock/SocketFds.h>

namespace folly {

// Including `gtest/gtest_prod.h` would make gtest/gmock a hard dep
// of the OSS build, which we do not want.
#define _FRIEND_TEST_FOR_ASYNC_FD_SOCKET(test_case_name, test_name) …

/**
 * Intended for use with Unix sockets. Unlike regular `AsyncSocket`:
 *  - Can send FDs via `writeChainWithFds` using socket ancillary data (see
 *    `man cmsg`).
 *  - Whenever handling regular reads, concurrently attempts to receive FDs
 *    included in incoming ancillary data.  Groups of received FDs are
 *    enqueued to be retrieved via `popNextReceivedFds`.
 *  - The "read ancillary data" and "sendmsg params" callbacks are built-in
 *    are NOT customizable.
 *
 * Implementation limitation: Unlike regular `AsyncSocket`, this currently
 * does not automatically send socket timestamping events.  This could
 * easily be added, but seems of limited utility for Unix sockets.
 */
class AsyncFdSocket : public AsyncSocket { … };

} // namespace folly