int uv_async_send(uv_async_t* handle) { /* Do a cheap read first. */ if (ACCESS_ONCE(int, handle->pending) != 0) return 0; if (cmpxchgi(&handle->pending, 0, 1) == 0) uv__async_send(handle->loop); return 0; }
static void uv__async_io(uv_loop_t* loop, uv__io_t* w, unsigned int events) { char buf[1024]; ssize_t r; QUEUE queue; QUEUE* q; uv_async_t* h; assert(w == &loop->async_io_watcher); for (;;) { r = read(w->fd, buf, sizeof(buf)); if (r == sizeof(buf)) continue; if (r != -1) break; if (errno == EAGAIN || errno == EWOULDBLOCK) break; if (errno == EINTR) continue; abort(); } QUEUE_MOVE(&loop->async_handles, &queue); while (!QUEUE_EMPTY(&queue)) { q = QUEUE_HEAD(&queue); h = QUEUE_DATA(q, uv_async_t, queue); QUEUE_REMOVE(q); QUEUE_INSERT_TAIL(&loop->async_handles, q); if (cmpxchgi(&h->pending, 1, 0) == 0) continue; if (h->async_cb == NULL) continue; h->async_cb(h); } }
static void uv__async_event(uv_loop_t* loop, struct uv__async* w, unsigned int nevents) { QUEUE queue; QUEUE* q; uv_async_t* h; QUEUE_MOVE(&loop->async_handles, &queue); while (!QUEUE_EMPTY(&queue)) { q = QUEUE_HEAD(&queue); h = QUEUE_DATA(q, uv_async_t, queue); QUEUE_REMOVE(q); QUEUE_INSERT_TAIL(&loop->async_handles, q); if (cmpxchgi(&h->pending, 1, 0) == 0) continue; if (h->async_cb == NULL) continue; h->async_cb(h); } }