Fix #107: some invalid usages of kqueue in ff_epoll.

1.Both EVFILT_READ and EVFILT_WRITE are values but not flags. It needs to check whether it is equal but not to do logic and.

2.If the read direction of the socket has shutdown, then the filter also sets EV_EOF in `flags`, and returns the socket error (if any) in `fflags`.

Author: logwang

lib/ff_epoll.c

@@ -69,10 +69,11 @@ ff_event_to_epoll(void **ev, struct kevent *kev)
     unsigned int event_one = 0;
     struct epoll_event **ppev = (struct epoll_event **)ev;
 
-    if (kev->filter & EVFILT_READ) {
-        event_one |= EPOLLIN;
-    } 
-    if (kev->filter & EVFILT_WRITE) {
+    if (kev->filter == EVFILT_READ) {
+        if (kev->data || !(kev->flags & EV_EOF)) {
+            event_one |= EPOLLIN;
+        }
+    } else if (kev->filter == EVFILT_WRITE) {
         event_one |= EPOLLOUT;
     }
 
@@ -81,7 +82,17 @@ ff_event_to_epoll(void **ev, struct kevent *kev)
     }
 
     if (kev->flags & EV_EOF) {
-        event_one |= EPOLLIN;        
+        event_one |= EPOLLHUP;
+
+        if (kev->fflags) {
+            event_one |= EPOLLERR;
+        }
+
+        if (kev->filter == EVFILT_READ) {
+            event_one |= EPOLLIN;
+        } else if (kev->filter == EVFILT_WRITE) {
+            event_one |= EPOLLERR;
+        }
     }
 
     (*ppev)->events   = event_one;