+ return tv;
+}
+
+bool event_loop(void) {
+ running = true;
+
+#ifndef HAVE_MINGW
+ fd_set readable;
+ fd_set writable;
+
+ while(running) {
+ struct timeval diff;
+ struct timeval *tv = get_time_remaining(&diff);
+ memcpy(&readable, &readfds, sizeof(readable));
+ memcpy(&writable, &writefds, sizeof(writable));
+
+ int fds = 0;
+
+ if(io_tree.tail) {
+ io_t *last = io_tree.tail->data;
+ fds = last->fd + 1;
+ }
+
+ int n = select(fds, &readable, &writable, NULL, tv);
+
+ if(n < 0) {
+ if(sockwouldblock(sockerrno)) {
+ continue;
+ } else {
+ return false;
+ }
+ }
+
+ if(!n) {
+ continue;
+ }
+
+ unsigned int curgen = io_tree.generation;
+
+ for splay_each(io_t, io, &io_tree) {
+ if(FD_ISSET(io->fd, &writable)) {
+ io->cb(io->data, IO_WRITE);
+ } else if(FD_ISSET(io->fd, &readable)) {
+ io->cb(io->data, IO_READ);
+ } else {
+ continue;
+ }
+
+ /*
+ There are scenarios in which the callback will remove another io_t from the tree
+ (e.g. closing a double connection). Since splay_each does not support that, we
+ need to exit the loop if that happens. That's okay, since any remaining events will
+ get picked up by the next select() call.
+ */
+ if(curgen != io_tree.generation) {
+ break;
+ }
+ }
+ }
+
+#else
+
+ while(running) {
+ struct timeval diff;
+ struct timeval *tv = get_time_remaining(&diff);
+ DWORD timeout_ms = tv ? (DWORD)(tv->tv_sec * 1000 + tv->tv_usec / 1000 + 1) : WSA_INFINITE;
+
+ if(!event_count) {
+ Sleep(timeout_ms);
+ continue;
+ }
+
+ /*
+ For some reason, Microsoft decided to make the FD_WRITE event edge-triggered instead of level-triggered,
+ which is the opposite of what select() does. In practice, that means that if a FD_WRITE event triggers,
+ it will never trigger again until a send() returns EWOULDBLOCK. Since the semantics of this event loop
+ is that write events are level-triggered (i.e. they continue firing until the socket is full), we need
+ to emulate these semantics by making sure we fire each IO_WRITE that is still writeable.
+
+ Note that technically FD_CLOSE has the same problem, but it's okay because user code does not rely on
+ this event being fired again if ignored.
+ */
+ unsigned int curgen = io_tree.generation;
+
+ for splay_each(io_t, io, &io_tree) {
+ if(io->flags & IO_WRITE && send(io->fd, NULL, 0, 0) == 0) {
+ io->cb(io->data, IO_WRITE);
+
+ if(curgen != io_tree.generation) {
+ break;
+ }
+ }
+ }
+
+ if(event_count > WSA_MAXIMUM_WAIT_EVENTS) {
+ WSASetLastError(WSA_INVALID_PARAMETER);
+ return(false);
+ }
+
+ WSAEVENT events[WSA_MAXIMUM_WAIT_EVENTS];
+ io_t *io_map[WSA_MAXIMUM_WAIT_EVENTS];
+ DWORD event_index = 0;
+
+ for splay_each(io_t, io, &io_tree) {
+ events[event_index] = io->event;
+ io_map[event_index] = io;
+ event_index++;
+ }
+
+ /*
+ * If the generation number changes due to event addition
+ * or removal by a callback we restart the loop.
+ */
+ curgen = io_tree.generation;
+
+ for(DWORD event_offset = 0; event_offset < event_count;) {
+ DWORD result = WSAWaitForMultipleEvents(event_count - event_offset, &events[event_offset], FALSE, timeout_ms, FALSE);
+
+ if(result == WSA_WAIT_TIMEOUT) {
+ break;
+ }
+
+ if(result >= event_count - event_offset) {
+ return(false);
+ }
+
+ /* Look up io in the map by index. */
+ event_index = result - event_offset;
+ io_t *io = io_map[event_index];
+
+ if(io->fd == -1) {
+ io->cb(io->data, 0);
+
+ if(curgen != io_tree.generation) {
+ break;
+ }
+ } else {
+ WSANETWORKEVENTS network_events;
+
+ if(WSAEnumNetworkEvents(io->fd, io->event, &network_events) != 0) {
+ return(false);
+ }
+
+ if(network_events.lNetworkEvents & READ_EVENTS) {
+ io->cb(io->data, IO_READ);
+
+ if(curgen != io_tree.generation) {
+ break;
+ }
+ }
+
+ /*
+ The fd might be available for write too. However, if we already fired the read callback, that
+ callback might have deleted the io (e.g. through terminate_connection()), so we can't fire the
+ write callback here. Instead, we loop back and let the writable io loop above handle it.
+ */
+ }
+
+ /* Continue checking the rest of the events. */
+ event_offset = event_index + 1;
+
+ /* Just poll the next time through. */
+ timeout_ms = 0;
+ }
+ }
+
+#endif
+
+ return true;
+}
+
+void event_exit(void) {
+ running = false;