1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
/**
* @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 "BasicEventQueue.h"
#include <event2/util.h> // for evutil_socket_t
#include <event2/thread.h>
#include <assert.h>
#include <easylogging++.h>
namespace uscxml {
BasicEventQueue::BasicEventQueue() {
}
BasicEventQueue::~BasicEventQueue() {
}
Event BasicEventQueue::dequeue(size_t blockMs) {
std::lock_guard<std::recursive_mutex> lock(_mutex);
if (blockMs > 0) {
// block for given milliseconds or until queue is filled
std::chrono::time_point<std::chrono::system_clock> updated, now;
std::chrono::milliseconds remain;
if (blockMs > (std::chrono::system_clock::duration::max)().count()) {
blockMs = (std::chrono::system_clock::duration::max)().count();
}
updated = now = std::chrono::system_clock::now();
remain = std::chrono::milliseconds(blockMs);
while (remain.count() > 0 && _queue.empty()) {
_cond.wait_for(_mutex, remain);
now = std::chrono::system_clock::now();
auto elapsed = now - updated;
remain -= std::chrono::duration_cast<std::chrono::milliseconds>(elapsed);
updated = now;
}
}
if (_queue.size() > 0) {
Event event = _queue.front();
_queue.pop_front();
// LOG(ERROR) << event.name;
return event;
}
return Event();
}
void BasicEventQueue::enqueue(const Event& event) {
std::lock_guard<std::recursive_mutex> lock(_mutex);
_queue.push_back(event);
_cond.notify_all();
}
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);
}
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);
data->eventQueue->_callbacks->eventReady(data->userData, data->eventUUID);
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;
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;
}
}
}
|