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/**
* @file
* @author 2016 Stefan Radomski (stefan.radomski@cs.tu-darmstadt.de)
* @copyright Simplified BSD
*
* @cond
* This program is free software: you can redistribute it and/or modify
* it under the terms of the FreeBSD license as published by the FreeBSD
* project.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
* You should have received a copy of the FreeBSD license along with this
* program. If not, see <http://www.opensource.org/licenses/bsd-license>.
* @endcond
*/
#include "BasicDelayedEventQueue.h"
#include <event2/util.h> // for evutil_socket_t
#include <event2/thread.h>
#include <assert.h>
#include "uscxml/interpreter/Logging.h"
namespace uscxml {
static void dummyCallback(evutil_socket_t fd, short what, void *arg) {
timeval tv;
tv.tv_sec = 365 * 24 * 3600;
tv.tv_usec = 0;
event *ev = *(event **)arg;
evtimer_add(ev, &tv);
}
BasicDelayedEventQueue::BasicDelayedEventQueue(DelayedEventQueueCallbacks* callbacks) {
_callbacks = callbacks;
#ifndef _WIN32
evthread_use_pthreads();
#else
evthread_use_windows_threads();
#endif
_eventLoop = event_base_new();
// see here: https://github.com/named-data/ndn.cxx/blob/master/scheduler/scheduler.cc
// and here: https://www.mail-archive.com/libevent-users@seul.org/msg01676.html
timeval tv;
tv.tv_sec = 365 * 24 * 3600;
tv.tv_usec = 0;
_dummyEvent = evtimer_new(_eventLoop, dummyCallback, &_dummyEvent);
evtimer_add(_dummyEvent, &tv);
_thread = NULL;
_isStarted = false;
start();
}
BasicDelayedEventQueue::~BasicDelayedEventQueue() {
stop();
evtimer_del(_dummyEvent);
event_free(_dummyEvent);
event_base_free(_eventLoop);
}
std::shared_ptr<DelayedEventQueueImpl> BasicDelayedEventQueue::create(DelayedEventQueueCallbacks* callbacks) {
return std::shared_ptr<DelayedEventQueueImpl>(new BasicDelayedEventQueue(callbacks));
}
void BasicDelayedEventQueue::timerCallback(evutil_socket_t fd, short what, void *arg) {
struct callbackData *data = (struct callbackData*)arg;
{
std::lock_guard<std::recursive_mutex> lock(data->eventQueue->_mutex);
if (data->eventQueue->_callbackData.find(data->eventUUID) == data->eventQueue->_callbackData.end())
return;
event_free(data->event);
}
// we cannot hold the mutex as this may trigger a delayed send
data->eventQueue->_callbacks->eventReady(data->userData, data->eventUUID);
{
std::lock_guard<std::recursive_mutex> lock(data->eventQueue->_mutex);
data->eventQueue->_callbackData.erase(data->eventUUID);
}
}
void BasicDelayedEventQueue::enqueueDelayed(const Event& event, size_t delayMs, const std::string& eventUUID) {
std::lock_guard<std::recursive_mutex> lock(_mutex);
if(_callbackData.find(eventUUID) != _callbackData.end()) {
cancelDelayed(eventUUID);
}
_callbackData[eventUUID].eventUUID = eventUUID;
_callbackData[eventUUID].userData = event;
_callbackData[eventUUID].eventQueue = this;
struct timeval delay = {static_cast<int32_t>(delayMs / 1000), static_cast<int32_t>((delayMs % 1000) * 1000)};
struct event* e = event_new(_eventLoop, -1, 0, timerCallback, &_callbackData[eventUUID]);
_callbackData[eventUUID].event = e;
evutil_gettimeofday(&(_callbackData[eventUUID].added), NULL);
evutil_timeradd(&delay, &_callbackData[eventUUID].added, &_callbackData[eventUUID].due);
event_add(e, &delay);
}
void BasicDelayedEventQueue::cancelAllDelayed() {
std::lock_guard<std::recursive_mutex> lock(_mutex);
while(_callbackData.size() > 0) {
std::pair<std::string, callbackData> item = *_callbackData.begin();
Event data = item.second.userData;
event_del(item.second.event);
event_free(item.second.event);
_callbackData.erase(item.first);
}
}
void BasicDelayedEventQueue::cancelDelayed(const std::string& eventId) {
std::lock_guard<std::recursive_mutex> lock(_mutex);
if(_callbackData.find(eventId) != _callbackData.end()) {
event_del(_callbackData[eventId].event);
event_free(_callbackData[eventId].event);
_callbackData.erase(eventId);
}
}
void BasicDelayedEventQueue::run(void* instance) {
BasicDelayedEventQueue* INSTANCE = (BasicDelayedEventQueue*)instance;
int result;
while(INSTANCE->_isStarted) {
/**
* EVLOOP_NO_EXIT_ON_EMPTY was removed in libevent2.1 - we are
* using the event in the far future approach to get blocking
* behavior back (see comments in contructor)
*/
// #ifndef EVLOOP_NO_EXIT_ON_EMPTY
// result = event_base_dispatch(INSTANCE->_eventLoop);
// #else
// TODO: this is polling when no events are enqueued
result = event_base_loop(INSTANCE->_eventLoop, EVLOOP_ONCE);
// assert(false); // NON-BLOCKING?!
//#endif
(void)result;
}
}
void BasicDelayedEventQueue::start() {
if (_isStarted) {
return;
}
_isStarted = true;
_thread = new std::thread(BasicDelayedEventQueue::run, this);
}
void BasicDelayedEventQueue::stop() {
if (_isStarted) {
_isStarted = false;
event_base_loopbreak(_eventLoop);
cancelAllDelayed();
}
if (_thread) {
_thread->join();
delete _thread;
_thread = NULL;
}
}
void BasicDelayedEventQueue::reset() {
std::lock_guard<std::recursive_mutex> lock(_mutex);
cancelAllDelayed();
_queue.clear();
}
Data BasicDelayedEventQueue::serialize() {
std::lock_guard<std::recursive_mutex> lock(_mutex);
if (_isStarted) {
_isStarted = false;
event_base_loopbreak(_eventLoop);
}
if (_thread) {
_thread->join();
delete _thread;
_thread = NULL;
}
Data serialized;
for (auto event : _queue) {
struct callbackData cb = _callbackData[event.getUUID()];
struct timeval delay = {0, 0};
struct timeval now = {0, 0};
uint64_t delayMs = 0;
evutil_gettimeofday(&now, NULL);
evutil_timersub(&delay, &cb.due, &now);
if (delay.tv_sec > 0 || (delay.tv_sec == 0 && delay.tv_usec > 0)) {
delayMs = delay.tv_sec * 1000 + delay.tv_usec / (double)1000;
}
Data delayedEvent;
delayedEvent["event"] = event;
delayedEvent["delay"] = Data(delayMs, Data::INTERPRETED);
serialized["BasicDelayedEventQueue"].array.push_back(event);
}
start();
return serialized;
}
void BasicDelayedEventQueue::deserialize(const Data& data) {
if (data.hasKey("BasicDelayedEventQueue")) {
std::lock_guard<std::recursive_mutex> lock(_mutex);
for (auto event : data["BasicDelayedEventQueue"].array) {
Event e = Event::fromData(event["event"]);
enqueueDelayed(e, strTo<size_t>(event["delay"]), e.getUUID());
}
}
}
}
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