From 29fdb3471ba993a4d129278129ec04e720890063 Mon Sep 17 00:00:00 2001
From: Fedor Indutny <fedor.indutny@gmail.com>
Date: Sat, 26 Oct 2013 01:06:12 +0400
Subject: [PATCH] unix: update events from pevents between polls

Watchers could be stopped between two `kevent()`/`epoll_wait()` calls
(which may happen in the same loop in `uv__io_poll()`), in such cases
`watcher->events` could be stale and won't be updated to
`watcher->pevents`.

Try to use and rely on `watcher->pevents` instead of blindly expecting
`watcher->events` to be always correct.
---
 src/unix/kqueue.c     |  4 ++--
 src/unix/linux-core.c | 11 ++++++++++-
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/unix/kqueue.c b/src/unix/kqueue.c
index 378903a6..d99d6e1b 100644
--- a/src/unix/kqueue.c
+++ b/src/unix/kqueue.c
@@ -191,7 +191,7 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       revents = 0;
 
       if (ev->filter == EVFILT_READ) {
-        if (w->events & UV__POLLIN) {
+        if (w->pevents & UV__POLLIN) {
           revents |= UV__POLLIN;
           w->rcount = ev->data;
         } else {
@@ -205,7 +205,7 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       }
 
       if (ev->filter == EVFILT_WRITE) {
-        if (w->events & UV__POLLOUT) {
+        if (w->pevents & UV__POLLOUT) {
           revents |= UV__POLLOUT;
           w->wcount = ev->data;
         } else {
diff --git a/src/unix/linux-core.c b/src/unix/linux-core.c
index e4c34a18..cb6df789 100644
--- a/src/unix/linux-core.c
+++ b/src/unix/linux-core.c
@@ -105,6 +105,7 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   uv__io_t* w;
   uint64_t base;
   uint64_t diff;
+  unsigned int masked_events;
   int nevents;
   int count;
   int nfds;
@@ -208,7 +209,15 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
         continue;
       }
 
-      w->cb(loop, w, pe->events);
+      /*
+       * Give users only events they're interested in. Prevents spurious
+       * callbacks when previous callback invocation in this loop has stopped
+       * the current watcher. Also, filters out events that users has not
+       * requested us to watch.
+       */
+      masked_events = pe->events & w->pevents;
+      if (masked_events != 0)
+        w->cb(loop, w, masked_events);
       nevents++;
     }