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EventLoop.cpp
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EventLoop.cpp
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//@author Jingyu Tong
//@email: jingyutong0806@gmail.com
#include "EventLoop.h"
#include "Epoll.h"
#include "Timer.h"
#include "Logging.h"
#include <poll.h>
#include <assert.h>
#include <pthread.h>
#include <unistd.h>
#include <sys/eventfd.h>
const int kPollTimeMs = 10000;
__thread EventLoop* t_loopInThisThread = 0;
//创建eventfd,返回对应fd
int createEventfd()
{
int evtfd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
if (evtfd < 0)
{
//LOG << "Failed in creating eventfd";
}
return evtfd;
}
EventLoop ::EventLoop()
: looping_(false),
threadID_(CurrentThread::tid()),
poller_(new Epoll(this)),
timer_queue_(new TimerManager(this)),
calling_pending_(false),
wakeup_fd_(createEventfd()),
wakeup_channel_(new Channel(this, wakeup_fd_))
{
//只允许一个EventLoop
if(t_loopInThisThread) {
} else {
t_loopInThisThread = this;
}
//wakeup_channel_->setReadCallback(std::bind(&EventLoop::handleEventfd, this));
wakeup_channel_->setReadCallback([this]() {this->handleEventfd(); });
wakeup_channel_->enableReading();
}
EventLoop :: ~EventLoop() {
assert(!looping_);
//处理eventfd和channel
wakeup_channel_->disableAll();
close(wakeup_fd_);
t_loopInThisThread = NULL;
}
void EventLoop :: loop() {
assert(!looping_);
assertInLoopThread();
looping_ = true;
quit_ = false;
while(!quit_) {
active_channels_.clear();
active_channels_ = poller_->poll(timer_queue_->getExpiredTime());
//分发给handler
for(auto it = active_channels_.begin(); it != active_channels_.end(); ++it ) {
(*it)->handleEvent();
}
doPendingFunctors();
handleExpired();
}
looping_ = false;
}
//退出
//在IO线程,则不用唤醒,下次loop循环将自动退出
//不在,则需要唤醒
void EventLoop::quit() {
quit_ = true;
if(!isInLoopThread()) {
wakeup();
}
}
//更新channel
void EventLoop::updateChannel(Channel* channel) {
assertInLoopThread(); //只允许IO线程更改channel
poller_->updateChannel(channel);
}
//提供定时器封装
//过一段时间运行callback
//将新生产的Timer指针返回,用于更新timer
TimerManager::TimerPointer EventLoop::runAfter(Timer::TimerCallback callback, int timeout) {
TimerManager::TimerPointer new_timer = timer_queue_->addTimer(std::move(callback), timeout);
return new_timer;
}
//更新runafter的时间,用来推迟或延后调用
void EventLoop::updateTimer(std::shared_ptr<Timer>& timer, int timeout) {
timer_queue_->updateTimer(timer, timeout);
}
//删除定时器
void EventLoop::cancelTimer(std::shared_ptr<Timer>& timer) {
//LOG << "begin to delete timer: " << timer->getExpTime();
timer_queue_->deleteTimer(timer);
}
//跨线程调用
//若在当前线程调用,直接进行回调
//否则,会唤醒IO线程,进行回调
void EventLoop::runInLoop(Functor callback) {
if (isInLoopThread()) {
callback();
}
else {
queueInLoop(std::move(callback));
}
}
//将回调放入vector中,并在必要时唤醒
void EventLoop::queueInLoop(Functor callback) {
{
MutexLockGuard lock(mutex_);
pending_functors_.push_back(std::move(callback));
}
//唤醒情况:
//1. 不是IO线程
//2. 如果在调用用户回调了,那么必须唤醒,否则不能及时被调用
//因为线程重新阻塞epoll中,如果不唤醒,将继续阻塞,不会调用用户回调
if(!isInLoopThread() || calling_pending_) {
wakeup();
}
}
//执行vector中的各个回调
//将回调列表移入临时对象,然后再依次调用,这样可以:
//1. 减小临界区长度
//2. 避免死锁(用户回调可能再次调用queueInLoop)
void EventLoop::doPendingFunctors() {
std::vector<Functor> functors;
calling_pending_ = true;
{
MutexLockGuard lock(mutex_);
functors.swap(pending_functors_);
}
for(const Functor& functor : functors) {
functor();
}
calling_pending_ = false;
}
//处理eventfd唤醒
void EventLoop::handleEventfd() {
uint64_t one = 1;
ssize_t n = read(wakeup_fd_, &one, sizeof one);
if(n != sizeof one) {
//LOG << "EventLoop::handleEventfd() reads" << n << "bytes";
}
}
//唤醒线程
void EventLoop::wakeup() {
uint64_t one = 1;
ssize_t n = write(wakeup_fd_, &one, sizeof one);
if(n != sizeof one) {
//LOG << "EventLoop::wakeup() writes" << n << "bytes";
}
}
void EventLoop::handleExpired() {
timer_queue_->handleExpiredEvent();
}