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libzmq
Commit a85d1e51 authored by Martin Lucina's avatar Martin Lucina Committed by Martin Sustrik
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zmq_poll(): Rewrite to use ZMQ_FD/ZMQ_EVENTS pt2 

Rewrite the select()-based zmq_poll() implementation to use
ZMQ_FD and ZMQ_EVENTS.

Also fix some corner cases: We should not pollute revents with
unrequested events, and we don't need to poll on ZMQ_FD at all
if a pollitem with no events set was passed in.
parent 6b1ca2cb
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Showing with 66 additions and 113 deletions
src/zmq.cpp
View file @ a85d1e51
......@@ -382,8 +382,8 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
// If the poll item is a 0MQ socket, we poll on the file descriptor
// retrieved by the ZMQ_FD socket option.
if (items_ [i].socket) {
size_t zmq_fd_size = sizeof (int);
if (items_ [i].socket && items_ [i].events) {
size_t zmq_fd_size = sizeof (zmq::fd_t);
if (zmq_getsockopt (items_ [i].socket, ZMQ_FD, &pollfds [i].fd,
&zmq_fd_size) == -1) {
free (pollfds);
......@@ -410,9 +410,8 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
if (rc == -1 && errno == EINTR) {
if (timeout_ < 0)
continue;
// Interrupted, no way to determine how much time is remaining
// from timeout so just return for now.
else {
// TODO: Calculate remaining timeout and restart poll ().
free (pollfds);
return 0;
}
......@@ -428,15 +427,18 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
// The poll item is a 0MQ socket. Retrieve pending events
// using the ZMQ_EVENTS socket option.
if (items_ [i].socket) {
if (pollfds [i].revents & POLLIN) {
if (items_ [i].socket && (pollfds [i].revents & POLLIN)) {
size_t zmq_events_size = sizeof (uint32_t);
if (zmq_getsockopt (items_ [i].socket, ZMQ_EVENTS,
&items_ [i].revents, &zmq_events_size) == -1) {
uint32_t zmq_events;
if (zmq_getsockopt (items_ [i].socket, ZMQ_EVENTS, &zmq_events,
&zmq_events_size) == -1) {
free (pollfds);
return -1;
}
}
if ((items_ [i].events & ZMQ_POLLOUT) && (zmq_events & ZMQ_POLLOUT))
items_ [i].revents |= ZMQ_POLLOUT;
if ((items_ [i].events & ZMQ_POLLIN) && (zmq_events & ZMQ_POLLIN))
items_ [i].revents |= ZMQ_POLLIN;
}
// Else, the poll item is a raw file descriptor, simply convert
// the events to zmq_pollitem_t-style format.
......@@ -465,154 +467,105 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
fd_set pollset_err;
FD_ZERO (&pollset_err);
zmq::app_thread_t *app_thread = NULL;
int nsockets = 0;
zmq::fd_t maxfd = zmq::retired_fd;
zmq::fd_t notify_fd = zmq::retired_fd;
zmq::fd_t maxfd = 0;
// Build the fd_sets for passing to select ().
for (int i = 0; i != nitems_; i++) {
// 0MQ sockets.
if (items_ [i].socket) {
// Get the app_thread the socket is living in. If there are two
// sockets in the same pollset with different app threads, fail.
zmq::socket_base_t *s = (zmq::socket_base_t*) items_ [i].socket;
if (app_thread) {
if (app_thread != s->get_thread ()) {
errno = EFAULT;
// If the poll item is a 0MQ socket we are interested in input on the
// notification file descriptor retrieved by the ZMQ_FD socket option.
if (items_ [i].socket && items_ [i].events) {
size_t zmq_fd_size = sizeof (zmq::fd_t);
zmq::fd_t notify_fd;
if (zmq_getsockopt (items_ [i].socket, ZMQ_FD, &notify_fd,
&zmq_fd_size) == -1)
return -1;
FD_SET (notify_fd, &pollset_in);
if (maxfd < notify_fd)
maxfd = notify_fd;
}
}
else
app_thread = s->get_thread ();
nsockets++;
continue;
}
// Raw file descriptors.
// Else, the poll item is a raw file descriptor. Convert the poll item
// events to the appropriate fd_sets.
else {
if (items_ [i].events & ZMQ_POLLIN)
FD_SET (items_ [i].fd, &pollset_in);
if (items_ [i].events & ZMQ_POLLOUT)
FD_SET (items_ [i].fd, &pollset_out);
if (items_ [i].events & ZMQ_POLLERR)
FD_SET (items_ [i].fd, &pollset_err);
if (maxfd == zmq::retired_fd || maxfd < items_ [i].fd)
if (maxfd < items_ [i].fd)
maxfd = items_ [i].fd;
}
// If there's at least one 0MQ socket in the pollset we have to poll
// for 0MQ commands. If ZMQ_POLL was not set, fail.
if (nsockets) {
notify_fd = app_thread->get_signaler ()->get_fd ();
if (notify_fd == zmq::retired_fd) {
errno = ENOTSUP;
return -1;
}
FD_SET (notify_fd, &pollset_in);
if (maxfd == zmq::retired_fd || maxfd < notify_fd)
maxfd = notify_fd;
}
bool block = (timeout_ < 0);
timeval timeout = {timeout_ / 1000000, timeout_ % 1000000};
timeval zero_timeout = {0, 0};
int nevents = 0;
// First iteration just check for events, don't block. Waiting would
// prevent exiting on any events that may already been signaled on
// 0MQ sockets.
fd_set inset, outset, errset;
// Wait for events. Ignore interrupts if there's infinite timeout.
while (true) {
memcpy (&inset, &pollset_in, sizeof (fd_set));
memcpy (&outset, &pollset_out, sizeof (fd_set));
memcpy (&errset, &pollset_err, sizeof (fd_set));
int rc = select (maxfd, &inset, &outset, &errset, &zero_timeout);
int rc = select (maxfd, &inset, &outset, &errset,
(timeout_ < 0) ? NULL : &timeout);
#if defined ZMQ_HAVE_WINDOWS
wsa_assert (rc != SOCKET_ERROR);
#else
if (rc == -1 && errno == EINTR && timeout_ >= 0)
if (rc == -1 && errno == EINTR) {
if (timeout_ < 0)
continue;
else
// TODO: Calculate remaining timeout and restart select ().
return 0;
errno_assert (rc >= 0 || (rc == -1 && errno == EINTR));
}
errno_assert (rc >= 0);
#endif
while (true) {
// Process 0MQ commands if needed.
if (nsockets && FD_ISSET (notify_fd, &inset))
if (!app_thread->process_commands (false, false)) {
errno = ETERM;
return -1;
break;
}
// Check for the events.
for (int i = 0; i != nitems_; i++) {
// If the poll item is a raw file descriptor, simply convert
// the events to zmq_pollitem_t-style format.
if (!items_ [i].socket) {
items_ [i].revents = 0;
// The poll item is a 0MQ socket. Retrieve pending events
// using the ZMQ_EVENTS socket option.
if (items_ [i].socket) {
size_t zmq_fd_size = sizeof (zmq::fd_t);
zmq::fd_t notify_fd;
if (zmq_getsockopt (items_ [i].socket, ZMQ_FD, &notify_fd,
&zmq_fd_size) == -1)
return -1;
if (FD_ISSET (notify_fd, &inset)) {
size_t zmq_events_size = sizeof (uint32_t);
uint32_t zmq_events;
if (zmq_getsockopt (items_ [i].socket, ZMQ_EVENTS, &zmq_events,
&zmq_events_size) == -1)
return -1;
if ((items_ [i].events & ZMQ_POLLOUT) &&
(zmq_events & ZMQ_POLLOUT))
items_ [i].revents |= ZMQ_POLLOUT;
if ((items_ [i].events & ZMQ_POLLIN) &&
(zmq_events & ZMQ_POLLIN))
items_ [i].revents |= ZMQ_POLLIN;
}
}
// Else, the poll item is a raw file descriptor, simply convert
// the events to zmq_pollitem_t-style format.
else {
if (FD_ISSET (items_ [i].fd, &inset))
items_ [i].revents |= ZMQ_POLLIN;
if (FD_ISSET (items_ [i].fd, &outset))
items_ [i].revents |= ZMQ_POLLOUT;
if (FD_ISSET (items_ [i].fd, &errset))
items_ [i].revents |= ZMQ_POLLERR;
if (items_ [i].revents)
nevents++;
continue;
}
// The poll item is a 0MQ socket.
zmq::socket_base_t *s = (zmq::socket_base_t*) items_ [i].socket;
items_ [i].revents = 0;
if ((items_ [i].events & ZMQ_POLLOUT) && s->has_out ())
items_ [i].revents |= ZMQ_POLLOUT;
if ((items_ [i].events & ZMQ_POLLIN) && s->has_in ())
items_ [i].revents |= ZMQ_POLLIN;
if (items_ [i].revents)
nevents++;
}
// If there's at least one event, or if we are asked not to block,
// return immediately.
if (nevents || (timeout.tv_sec == 0 && timeout.tv_usec == 0))
break;
// Wait for events. Ignore interrupts if there's infinite timeout.
while (true) {
memcpy (&inset, &pollset_in, sizeof (fd_set));
memcpy (&outset, &pollset_out, sizeof (fd_set));
memcpy (&errset, &pollset_err, sizeof (fd_set));
rc = select (maxfd, &inset, &outset, &errset,
block ? NULL : &timeout);
#if defined ZMQ_HAVE_WINDOWS
wsa_assert (rc != SOCKET_ERROR);
#else
if (rc == -1 && errno == EINTR) {
if (timeout_ < 0)
continue;
else {
rc = 0;
break;
}
}
errno_assert (rc >= 0);
#endif
break;
}
// If timeout was hit with no events signaled, return zero.
if (rc == 0)
break;
// If timeout was already applied, we don't want to poll anymore.
// Setting timeout to zero will cause termination of the function
// once the events we've got are processed.
if (!block)
timeout = zero_timeout;
}
return nevents;
#else
......
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