fix(event):去除FdEvent的kHupEvent事件，同时修复之前epoll因EPOLLHUP引起的Loop空跑问题

Author: hevake

modules/event/engines/epoll/fd_event.cpp

@@ -79,9 +79,6 @@ bool EpollFdEvent::enable()
     if (events_ & kExceptEvent)
         ++d_->except_event_num;
 
-    if (events_ & kHupEvent)
-        ++d_->hup_event_num;
-
     d_->fd_events.push_back(this);
 
     reloadEpoll();
@@ -104,9 +101,6 @@ bool EpollFdEvent::disable()
     if (events_ & kExceptEvent)
         --d_->except_event_num;
 
-    if (events_ & kHupEvent)
-        --d_->hup_event_num;
-
     auto iter = std::find(d_->fd_events.begin(), d_->fd_events.end(), this);
     d_->fd_events.erase(iter);
 
@@ -136,9 +130,6 @@ void EpollFdEvent::reloadEpoll()
     if (d_->except_event_num > 0)
         new_events |= EPOLLERR;
 
-    if (d_->hup_event_num > 0)
-        new_events |= EPOLLHUP;
-
     d_->ev.events = new_events;
 
     if (old_events == 0) {
@@ -173,29 +164,34 @@ void EpollFdEvent::OnEventCallback(uint32_t events, void *obj)
         tbox_events |= kExceptEvent;
     }
 
+    bool is_got_hup = false;
+
     if (events & EPOLLHUP) {
         events &= ~EPOLLHUP;
-        tbox_events |= kHupEvent;
+        is_got_hup = true;
     }
 
     //! 要先复制一份，因为在for中很可能会改动到d->fd_events，引起迭代器失效问题
     auto tmp = d->fd_events;
-    for (auto event : tmp)
+    for (auto event : tmp) {
         event->onEvent(tbox_events);
 
+        //! 在epoll中，无论有没有监听EPOLLHUP，在对端close了fd时都会触发本端EPOLLHUP事件
+        //! 只要发生了EPOLLHUB事件，就无法停止它，得强制disable()所有fd关联FdEvent
+        //! 否则它会一直触发事件，导致Loop空跑，CPU占满问题
+        if (is_got_hup) {
+            //! 将HUP事件当成可读事件，上层读到0字节则表示对端已关闭
+            event->onEvent(kReadEvent);
+            event->disable();   //! 强制关闭事件
+        }
+    }
+
     if (events)
         LogWarn("unhandle events:%08X, fd:%d", events, d->fd);
 }
 
 void EpollFdEvent::onEvent(short events)
 {
-    /**
-     * 由于EPOLLHUP会一直触发，所以无论事件有没有监听HupEvent，只要发生了EPOLLHUB事件，
-     * 对应fd所有的事件都要强制disable()。否则会导致Loop空跑问题。
-     */
-    if (events & kHupEvent)
-        disable();
-
     if (events_ & events) {
         if (is_stop_after_trigger_)
             disable();

modules/event/engines/epoll/types.h

@@ -37,7 +37,6 @@ struct EpollFdSharedData {
     int read_event_num = 0;     //!< 监听可读事件的FdEvent个数
     int write_event_num = 0;    //!< 监听可写事件的FdEvent个数
     int except_event_num = 0;   //!< 监听异常事件的FdEvent个数
-    int hup_event_num = 0;      //!< 监听挂起事件的FdEvent个数
 
     std::vector<EpollFdEvent*> fd_events;
 };

modules/event/fd_event.h

@@ -33,7 +33,6 @@ class FdEvent : public Event {
         kReadEvent   = 0x01,    //!< 可读事件
         kWriteEvent  = 0x02,    //!< 可写事件
         kExceptEvent = 0x04,    //!< 异常事件
-        kHupEvent    = 0x08,    //!< 断开事件
     };
 
     using Event::Event;

modules/event/fd_event_test.cpp

@@ -23,6 +23,7 @@
 
 #include <errno.h>
 #include <cstring>
+#include <tbox/base/log.h>
 #include <tbox/base/log_output.h>
 
 #include "loop.h"
@@ -367,18 +368,18 @@ TEST(FdEvent, Exception)
         ASSERT_TRUE(write_fd_event != nullptr);
 
         int run_time = 0;
+        size_t recv_bytes = 0;
 
-        EXPECT_TRUE(read_fd_event->initialize(read_fd, FdEvent::kReadEvent | FdEvent::kHupEvent, Event::Mode::kPersist));
+        EXPECT_TRUE(read_fd_event->initialize(read_fd, FdEvent::kReadEvent, Event::Mode::kPersist));
         read_fd_event->setCallback([&](short events){
             if (events & FdEvent::kReadEvent) {
                 char data[100] = { 0 };
                 ssize_t len = read(read_fd, data, sizeof(data));
-                EXPECT_EQ(len, sizeof(int));
-            }
-
-            if (events & FdEvent::kHupEvent) {
-                ++run_time;
-                loop->exitLoop();
+                recv_bytes += len;
+                if (len == 0) {
+                    ++run_time;
+                    loop->exitLoop();
+                }
             }
         });
 
@@ -396,10 +397,10 @@ TEST(FdEvent, Exception)
 
         write_fd_event->enable();
 
-        loop->exitLoop(std::chrono::milliseconds(10));
         loop->runLoop();
 
         EXPECT_EQ(run_time, 1);
+        EXPECT_EQ(recv_bytes, sizeof(int));
 
         read_fd_event->disable();
         write_fd_event->disable();