-
-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;
- }
-
- 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 now. That's okay, since any remaining events will get picked
- up by the next select() call.
- */
- break;
- }
- }
-
-#else
-
- while(running) {
- struct timeval diff;
- struct timeval *tv = get_time_remaining(&diff);
- DWORD timeout_ms = tv ? (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 < WSA_WAIT_EVENT_0 || result >= WSA_WAIT_EVENT_0 + event_count - event_offset) {
- return(false);
- }
-
- /* Look up io in the map by index. */
- event_index = result - WSA_WAIT_EVENT_0 + 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;
-}