DbusEventDispatcher.h

/*
* If not stated otherwise in this file or this component's LICENSE file the
* following copyright and licenses apply:
*
* Copyright 2020 Sky UK
*
* 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.
*/
/*
 * DbusEventDispatcher.h
 *
 */
 
#ifndef AI_IPC_DBUSEVENTDISPATCHER_H
#define AI_IPC_DBUSEVENTDISPATCHER_H
 
#include <dbus/dbus.h>
 
#include <thread>
#include <cstdint>
#include <memory>
#include <queue>
#include <mutex>
#include <condition_variable>
#include <functional>
 
namespace AI_IPC
{
 
// -----------------------------------------------------------------------------
class DbusEventDispatcher
{
public:
    DbusEventDispatcher();
 
    ~DbusEventDispatcher();
 
public:
    void startEventDispatcher(DBusConnection *connection);
 
    void stopEventDispatcher();
 
public:
    template< class Function, class... Args >
    bool callInEventLoop(Function&& f, Args&&... args)
    {
        return this->callInEventLoopImpl(std::bind(std::forward<Function>(f),
                                                   std::forward<Args>(args)...));
    }
 
    template< class Function >
    bool callInEventLoop(Function func)
    {
        return this->callInEventLoopImpl(func);
    }
 
private:
    void eventDispatcherThreadFn();
 
    void cleanupAllEvents();
 
private:
    static void dispatchStatusCb(DBusConnection *connection, DBusDispatchStatus status, void *userData);
 
    static void wakeUpCb(void *userData);
 
private:
    DBusConnection* mDbusConnection;
 
    std::thread mEventDispatcherThread;
 
    int mDeathEventFd;
    int mWakeupEventFd;
    int mDispatchEventFd;
 
private:
    bool callInEventLoopImpl(const std::function<void()>& func);
 
    uint64_t mCallCounter;
    std::mutex mCallLock;
    std::condition_variable mCallCondVar;
    std::queue< std::pair<uint64_t, std::function<void()>> > mCallQueue;
 
};
 
} // namespace AI_IPC
 
#endif // !defined(AI_IPC_DBUSEVENTDISPATCHER_H)