[英]C++ Event Manager Multi-Thread Reliable?
我使像EventManager.h下面的類事件管理器
#ifndef EVENTMANAGER_H
#define EVENTMANAGER_H
#include <thread>
#include <mutex>
#include <chrono>
#include <atomic>
#include <condition_variable>
#include <vector>
#include "../../object/EObject.h"
class EventManager : public EObject {
public:
EventManager();
virtual ~EventManager();
int start_event();
void stop_event();
void add(const char* name, int interval, EObject * instance);
private:
static const int MAX_EVENT = 10;
std::atomic<int> event_total;
struct {
int event_id;
std::string event_name;
int interval;
std::atomic<bool> next_execute;
EObject * instance;
std::unique_ptr<std::condition_variable> cv;
std::unique_ptr<std::mutex> mtx;
} my_event[MAX_EVENT];
std::thread * event_thread;
std::atomic<bool> shall_stop;
std::atomic<bool> has_stopped;
std::atomic<int> worker_delay;
void worker();
//timing
std::vector<std::unique_ptr<std::thread>> timing_work;
void timing(int id);
};
#endif /* EVENTMANAGER_H */
EventManager.cpp
#include <iostream>
#include "EventManager.h"
#include "../../object/EVariant.h"
using namespace std;
EventManager::EventManager() {
event_thread = nullptr;
has_stopped = true;
shall_stop = false;
worker_delay = 5; //milli second
event_total = 0;
}
EventManager::~EventManager() {
}
int EventManager::start_event() {
if (event_thread) {
cout << "Event thread can not create\n" << flush;
return -1;
} else {
event_thread = new std::thread([this] {
this->worker();
});
cout << "Event thread created\n" << flush;
}
return 0;
}
void EventManager::stop_event() {
shall_stop = true;
for (int i = 0; i < 5; i++) {
this_thread::sleep_for(chrono::microseconds(10));
if (has_stopped) break;
}
delete event_thread;
event_thread = nullptr;
}
void EventManager::worker() {
has_stopped = false;
while (1) {
if (shall_stop) break;
for (int i = 0; i < event_total; i++) {
// cout << "Event Manager: " << my_event[i].event_name << " - checking \n" << flush;
if (my_event[i].next_execute) {
EVariant var = EVariant();
var.push("event_name", my_event[i].event_name);
my_event[i].instance->update(var);
my_event[i].next_execute = false;
{
condition_variable * cv = my_event[i].cv.get();
mutex * mtx = my_event[i].mtx.get();
unique_lock<mutex> lock(*mtx);
cv->notify_one();
// cout << "Event Manager: " << my_event[i].event_name << " - hey wakeup \n" << flush;
}
}
}
this_thread::sleep_for(chrono::milliseconds(worker_delay));
}
shall_stop = false;
has_stopped = true;
}
void EventManager::timing(int id) {
int _id = id;
cout << "Timing thread: " << my_event[_id].event_name << " - " << this_thread::get_id() << " - i was born\n" << flush;
while (1) {
int delay = my_event[_id].interval;
// cout << "Event Manager: " << my_event[_id].event_name << " - i delay \n" << flush;
this_thread::sleep_for(chrono::milliseconds(delay));
my_event[_id].next_execute = true;
{
// cout << "Event Manager: " << my_event[_id].event_name << " - i sleep \n" << flush;
condition_variable * cv = my_event[_id].cv.get();
mutex * mtx = my_event[_id].mtx.get();
unique_lock<mutex> lock(*mtx);
cv->wait(lock);
// cout << "Event Manager: " << my_event[_id].event_name << " - OK wakeup \n" << flush;
}
}
cout << "Timing thread: " << id << " - i'm quit\n" << flush;
}
void EventManager::add(const char* name, int interval, EObject* instance) {
cout << "Event adding : " << name << "\n" << flush;
event_total += 1;
int id = event_total - 1;
my_event[id].event_id = id;
my_event[id].event_name = name;
my_event[id].interval = interval;
my_event[id].instance = instance;
my_event[id].next_execute = false;
unique_ptr<mutex> mtx(new mutex());
my_event[id].mtx = std::move(mtx);
unique_ptr<condition_variable> cov(new condition_variable());
my_event[id].cv = std::move(cov);
//create thread delay
// std::thread th([this] {
// this->timing(event_total - 1);
// });
unique_ptr<thread> thd(new thread([this] {
this->timing(event_total - 1);
}));
// timing_collection.push_back(std::move(th));
timing_work.push_back(std::move(thd));
}
調用
//event i2c communication
p_event_manager.emplace("I2C", new EventManager());
p_event_manager.at("I2C")->add("i2c_buffer", 10, pI2c.at("i2c-1"));
p_event_manager.at("I2C")->add("i2c_poll_tb", 30, p_touch_button.at("TouchButton1"));
p_event_manager.at("I2C")->add("i2c_micro_poll", 50, bsc_app);
p_event_manager.at("I2C")->start_event();
算法:調用添加函數時,該函數將添加結構並創建新線程以延遲周期,該線程將移至向量,該線程將更改事件標志,以供下一次在事件主線程上執行。
問題:問題通常是延遲線程未成功創建,因此未調用該事件。 如何解決?
不建議在計時器函數中使用this_thread :: sleep_for(),並且您可能會在睡眠周期中錯過觸發點。 對觸發點的過多輪詢也會導致不必要的CPU周期浪費。 因此,您應該主要依賴在准確時間觸發而不輪詢的condition_variables。
例如,您可以將std::pair<time_point,thread_id>
推入按時間順序排序的有序容器中。 另請參閱優先級隊列是否可以滿足您的需求。 您的例程過於復雜,簡單有其自身的品質。
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