C++11 thread condition_variable mutex 綜合使用

#include <mutex>
#include <condition_variable>
#include <chrono>
#include <thread>
#include <glog/logging.h>

class Event {
public:
    Event();
    ~Event();

    bool wait(std::chrono::milliseconds millisec);
    void notify();

private:
    std::mutex m_lock;
    std::condition_variable m_cond;
};

Event::Event() {
}

Event::~Event() {
}

bool Event::wait(std::chrono::milliseconds millisec) {
    LOG(INFO)<< "before lock";
    std::unique_lock<std::mutex> l(m_lock);
    auto cv = m_cond.wait_for(l, millisec);
    if (cv == std::cv_status::no_timeout) {
        return true;
    }
    return false;
}

void Event::notify() {
    m_cond.notify_all();
}

class App {
public:
    App();
    ~App();

    bool start();
    static void threadRun(void * p);
    void run();
    void stop();
    void postExit();

private:
    Event m_event;
    std::mutex m_lock;
    std::thread * m_thread;
};

App::App() {
    m_thread = NULL;
}

App::~App() {
    m_thread = NULL;
}

bool App::start() {
    std::unique_lock<std::mutex> l(m_lock);
    if (m_thread != NULL) {
        LOG(INFO)<<"thread running";
        return false;
    }
    m_thread = new std::thread(threadRun, this);
    if (m_thread == NULL) {
        LOG(INFO)<<"create thread failed";
        return false;
    }
    LOG(INFO)<< "create thread success";
    return true;
}

void App::threadRun(void *p) {
    App * pThis = (App*) p;
    pThis->run();
}

void App::run() {
    while (!this->m_event.wait(std::chrono::milliseconds(1002))) {
        LOG(INFO)<< "sleep";
    }
}

void App::postExit() {
    delete this->m_thread;
    this->m_thread = NULL;
}

void App::stop() {
    std::unique_lock<std::mutex> l(m_lock);
    this->m_event.notify();
    this->m_thread->join();
    postExit();
}

int main(int ac, char**av) {
    google::InitGoogleLogging(av[0]);

    FLAGS_alsologtostderr = true;
    FLAGS_logtostderr = true;

    LOG(INFO)<< "app started";

    std::unique_ptr<App> p(new App);
    if (!p->start()) {
        LOG(INFO)<< "start failed";
        return 1;
    }
    for (auto i = 0; i < 3; i++) {
        std::this_thread::sleep_for(std::chrono::seconds(2));
        LOG(INFO)<<"main thread sleep";
    }
    p->stop();

    LOG(INFO)<< "main thread done";
    return 0;
}