zircon/system/core/devmgr/devhost/connection-destroyer.h

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#pragma once

#include <lib/async/cpp/receiver.h>
#include <zircon/syscalls.h>

namespace devmgr {

class DeviceControllerConnection;
struct ProxyIostate;

// Handles destroying Connection objects in the single-threaded DevhostAsyncLoop().
// This allows us to prevent races between canceling waiting on the connection
// channel and executing the connection's handler.
class ConnectionDestroyer {
public:
    static ConnectionDestroyer* Get() {
        static ConnectionDestroyer destroyer;
        return &destroyer;
    }

    zx_status_t QueueDeviceControllerConnection(async_dispatcher_t* dispatcher,
                                                DeviceControllerConnection* conn);
    zx_status_t QueueProxyConnection(async_dispatcher_t* dispatcher,
                                     ProxyIostate* conn);

private:
    ConnectionDestroyer() = default;

    ConnectionDestroyer(const ConnectionDestroyer&) = delete;
    ConnectionDestroyer& operator=(const ConnectionDestroyer&) = delete;

    ConnectionDestroyer(ConnectionDestroyer&&) = delete;
    ConnectionDestroyer& operator=(ConnectionDestroyer&&) = delete;

    static void Handler(async_dispatcher_t* dispatcher, async::Receiver* receiver,
                        zx_status_t status, const zx_packet_user_t* data);

    enum class Type {
        DeviceController,
        Proxy,
    };

    async::Receiver receiver_{ConnectionDestroyer::Handler};
};

} // namespace devmgr