C++ QUEUE_HEAD函数代码示例

static void uv__cf_loop_cb(void* arg) {
  uv_loop_t* loop;
  QUEUE* item;
  QUEUE split_head;
  uv__cf_loop_signal_t* s;

  loop = arg;

  uv_mutex_lock(&loop->cf_mutex);
  QUEUE_INIT(&split_head);
  if (!QUEUE_EMPTY(&loop->cf_signals)) {
    QUEUE* split_pos = QUEUE_HEAD(&loop->cf_signals);
    QUEUE_SPLIT(&loop->cf_signals, split_pos, &split_head);
  }
  uv_mutex_unlock(&loop->cf_mutex);

  while (!QUEUE_EMPTY(&split_head)) {
    item = QUEUE_HEAD(&split_head);

    s = QUEUE_DATA(item, uv__cf_loop_signal_t, member);

    /* This was a termination signal */
    if (s->cb == NULL)
      CFRunLoopStop(loop->cf_loop);
    else
      s->cb(s->arg);

    QUEUE_REMOVE(item);
    free(s);
  }
}

void uv__cf_loop_cb(void* arg) {
  uv_loop_t* loop;
  QUEUE* item;
  QUEUE split_head;
  uv__cf_loop_signal_t* s;

  loop = arg;

  uv_mutex_lock(&loop->cf_mutex);
  QUEUE_INIT(&split_head);
  if (!QUEUE_EMPTY(&loop->cf_signals)) {
    QUEUE* split_pos = QUEUE_HEAD(&loop->cf_signals);
    QUEUE_SPLIT(&loop->cf_signals, split_pos, &split_head);
  }
  uv_mutex_unlock(&loop->cf_mutex);

  while (!QUEUE_EMPTY(&split_head)) {
    item = QUEUE_HEAD(&split_head);

    s = QUEUE_DATA(item, uv__cf_loop_signal_t, member);
    s->cb(s->arg);

    QUEUE_REMOVE(item);
    free(s);
  }
}

void uv__work_done(uv_async_t* handle) {
  struct uv__work* w;
  uv_loop_t* loop;
  QUEUE* q;
  QUEUE wq;
  int err;

  loop = container_of(handle, uv_loop_t, wq_async);
  QUEUE_INIT(&wq);

  // uv_mutex_lock(&loop->wq_mutex);
  if (!QUEUE_EMPTY(&loop->wq)) {
    q = QUEUE_HEAD(&loop->wq);
    QUEUE_SPLIT(&loop->wq, q, &wq);
  }
  // uv_mutex_unlock(&loop->wq_mutex);

  while (!QUEUE_EMPTY(&wq)) {
    q = QUEUE_HEAD(&wq);
    QUEUE_REMOVE(q);

    w = container_of(q, struct uv__work, wq);
    w->done(w, 0, NULL, 0);
  }
}

void uv__work_done(uv_async_t* handle) {
  struct uv__work* w;
  uv_loop_t* loop;
  QUEUE* q;
  QUEUE wq;
  int err;

  loop = container_of(handle, uv_loop_t, wq_async);
  QUEUE_INIT(&wq);

  uv_mutex_lock(&loop->wq_mutex);
  if (!QUEUE_EMPTY(&loop->wq)) {
    q = QUEUE_HEAD(&loop->wq);
    QUEUE_SPLIT(&loop->wq, q, &wq);
  }
  uv_mutex_unlock(&loop->wq_mutex);

  while (!QUEUE_EMPTY(&wq)) {
    q = QUEUE_HEAD(&wq);
    QUEUE_REMOVE(q);

    w = container_of(q, struct uv__work, wq);
    err = (w->work == uv__cancelled) ? UV_ECANCELED : 0;
    w->done(w, err);
  }
}

/**
 * @brief default NPE event processing callback
 *
 * @param npeID ID of the NPE that generated the event
 * @param msg NPE message (encapsulated event)
 *
 * Creates an event object on the Ethernet event processor queue
 * and signals the new event by incrementing the event queue semaphore.
 * Events are processed by @ref ixEthDBEventProcessorLoop() which runs
 * at user level.
 *
 * @see ixEthDBEventProcessorLoop()
 *
 * @warning do not call directly
 *
 * @internal
 */
IX_ETH_DB_PUBLIC
void ixEthDBNPEEventCallback(IxNpeMhNpeId npeID, IxNpeMhMessage msg)
{
    PortEvent *local_event;

    IX_ETH_DB_IRQ_EVENTS_TRACE("DB: (Events) new event received by processor callback from port %d, id 0x%X\n", IX_ETHNPE_NODE_AND_PORT_TO_PHYSICAL_ID(npeID,0), NPE_MSG_ID(msg), 0, 0, 0, 0);

    if (CAN_ENQUEUE(&eventQueue))
    {
        TEST_FIXTURE_LOCK_EVENT_QUEUE;

        local_event = QUEUE_HEAD(&eventQueue);

        /* create event structure on queue */
        local_event->eventType = NPE_MSG_ID(msg);
        local_event->portID    = IX_ETHNPE_NODE_AND_PORT_TO_PHYSICAL_ID(npeID,0);
        
        /* update queue */
        PUSH_UPDATE_QUEUE(&eventQueue);

        TEST_FIXTURE_UNLOCK_EVENT_QUEUE;

        IX_ETH_DB_IRQ_EVENTS_TRACE("DB: (Events) Waking up main processor loop...\n", 0, 0, 0, 0, 0, 0);

        /* increment event queue semaphore */
        ixOsalSemaphorePost(&eventQueueSemaphore);
    }
    else
    {
        IX_ETH_DB_IRQ_EVENTS_TRACE("DB: (Events) Warning: could not enqueue event (overflow)\n", 0, 0, 0, 0, 0, 0);
    }
}

static void uv__write_callbacks(uv_stream_t* stream) {
  uv_write_t* req;
  QUEUE* q;

  while (!QUEUE_EMPTY(&stream->write_completed_queue)) {
    /* Pop a req off write_completed_queue. */
    q = QUEUE_HEAD(&stream->write_completed_queue);
    req = QUEUE_DATA(q, uv_write_t, queue);
    QUEUE_REMOVE(q);
    uv__req_unregister(stream->loop, req);

    if (req->bufs != NULL) {
      stream->write_queue_size -= uv__write_req_size(req);
      if (req->bufs != req->bufsml)
        free(req->bufs);
      req->bufs = NULL;
    }

    /* NOTE: call callback AFTER freeing the request data. */
    if (req->cb)
      req->cb(req, req->error);
  }

  assert(QUEUE_EMPTY(&stream->write_completed_queue));
}

void uv__udp_finish_close(uv_udp_t* handle) {
  uv_udp_send_t* req;
  QUEUE* q;

  assert(!uv__io_active(&handle->io_watcher, UV__POLLIN | UV__POLLOUT));
  assert(handle->io_watcher.fd == -1);

  while (!QUEUE_EMPTY(&handle->write_queue)) {
    q = QUEUE_HEAD(&handle->write_queue);
    QUEUE_REMOVE(q);

    req = QUEUE_DATA(q, uv_udp_send_t, queue);
    req->status = -ECANCELED;
    QUEUE_INSERT_TAIL(&handle->write_completed_queue, &req->queue);
  }

  uv__udp_run_completed(handle);

  assert(handle->send_queue_size == 0);
  assert(handle->send_queue_count == 0);

  /* Now tear down the handle. */
  handle->recv_cb = NULL;
  handle->alloc_cb = NULL;
  /* but _do not_ touch close_cb */
}

void uv__udp_finish_close(uv_udp_t* handle) {
  uv_udp_send_t* req;
  QUEUE* q;

  assert(!uv__io_active(&handle->io_watcher, UV__POLLIN | UV__POLLOUT));
  assert(handle->io_watcher.fd == -1);

  uv__udp_run_completed(handle);

  while (!QUEUE_EMPTY(&handle->write_queue)) {
    q = QUEUE_HEAD(&handle->write_queue);
    QUEUE_REMOVE(q);

    req = QUEUE_DATA(q, uv_udp_send_t, queue);
    uv__req_unregister(handle->loop, req);

    if (req->bufs != req->bufsml)
      free(req->bufs);
    req->bufs = NULL;

    if (req->send_cb != NULL)
      req->send_cb(req, -ECANCELED);
  }

  /* Now tear down the handle. */
  handle->recv_cb = NULL;
  handle->alloc_cb = NULL;
  /* but _do not_ touch close_cb */
}

static void uv__udp_run_completed(uv_udp_t* handle) {
  uv_udp_send_t* req;
  QUEUE* q;

  while (!QUEUE_EMPTY(&handle->write_completed_queue)) {
    q = QUEUE_HEAD(&handle->write_completed_queue);
    QUEUE_REMOVE(q);

    req = QUEUE_DATA(q, uv_udp_send_t, queue);
    uv__req_unregister(handle->loop, req);

    if (req->bufs != req->bufsml)
      free(req->bufs);
    req->bufs = NULL;

    if (req->send_cb == NULL)
      continue;

    /* req->status >= 0 == bytes written
     * req->status <  0 == errno
     */
    if (req->status >= 0)
      req->send_cb(req, 0);
    else
      req->send_cb(req, req->status);
  }
}

static void uv__inotify_read(uv_loop_t* loop,
                             uv__io_t* dummy,
                             unsigned int events) {
  const struct uv__inotify_event* e;
  struct watcher_list* w;
  uv_fs_event_t* h;
  QUEUE queue;
  QUEUE* q;
  const char* path;
  ssize_t size;
  const char *p;
  /* needs to be large enough for sizeof(inotify_event) + strlen(path) */
  char buf[4096];

  while (1) {
    do
      size = read(loop->inotify_fd, buf, sizeof(buf));
    while (size == -1 && errno == EINTR);

    if (size == -1) {
      assert(errno == EAGAIN || errno == EWOULDBLOCK);
      break;
    }

    assert(size > 0); /* pre-2.6.21 thing, size=0 == read buffer too small */

    /* Now we have one or more inotify_event structs. */
    for (p = buf; p < buf + size; p += sizeof(*e) + e->len) {
      e = (const struct uv__inotify_event*)p;

      events = 0;
      if (e->mask & (UV__IN_ATTRIB|UV__IN_MODIFY))
        events |= UV_CHANGE;
      if (e->mask & ~(UV__IN_ATTRIB|UV__IN_MODIFY))
        events |= UV_RENAME;

      w = find_watcher(loop, e->wd);
      if (w == NULL)
        continue; /* Stale event, no watchers left. */

      /* inotify does not return the filename when monitoring a single file
       * for modifications. Repurpose the filename for API compatibility.
       * I'm not convinced this is a good thing, maybe it should go.
       */
      path = e->len ? (const char*) (e + 1) : uv__basename_r(w->path);

      QUEUE_MOVE(&w->watchers, &queue);
      while (!QUEUE_EMPTY(&queue)) {
        q = QUEUE_HEAD(&queue);
        h = QUEUE_DATA(q, uv_fs_event_t, watchers);

        QUEUE_REMOVE(q);
        QUEUE_INSERT_TAIL(&w->watchers, q);

        h->cb(h, path, events, 0);
      }
    }
  }
}

static Token stack_pop(QUEUE *stack)
{
  QUEUE *h = QUEUE_HEAD(stack);
  queue_item *item = queue_node_data(h);
  QUEUE_REMOVE(&item->node);
  Token token = item->item;
  free(item);
  return token;
}

static void uv__udp_run_pending(uv_udp_t* handle) {
  uv_udp_send_t* req;
  QUEUE* q;
  struct msghdr h;
  ssize_t size;

  while (!QUEUE_EMPTY(&handle->write_queue)) {
    q = QUEUE_HEAD(&handle->write_queue);
    assert(q != NULL);

    req = QUEUE_DATA(q, uv_udp_send_t, queue);
    assert(req != NULL);

    memset(&h, 0, sizeof h);
    h.msg_name = &req->addr;
    h.msg_namelen = (req->addr.sin6_family == AF_INET6 ?
      sizeof(struct sockaddr_in6) : sizeof(struct sockaddr_in));
    h.msg_iov = (struct iovec*)req->bufs;
    h.msg_iovlen = req->bufcnt;

    do {
      size = sendmsg(handle->io_watcher.fd, &h, 0);
    }
    while (size == -1 && errno == EINTR);

    /* TODO try to write once or twice more in the
     * hope that the socket becomes readable again?
     */
    if (size == -1 && (errno == EAGAIN || errno == EWOULDBLOCK))
      break;

    req->status = (size == -1 ? -errno : size);

#ifndef NDEBUG
    /* Sanity check. */
    if (size != -1) {
      ssize_t nbytes;
      int i;

      for (nbytes = i = 0; i < req->bufcnt; i++)
        nbytes += req->bufs[i].len;

      assert(size == nbytes);
    }
#endif

    /* Sending a datagram is an atomic operation: either all data
     * is written or nothing is (and EMSGSIZE is raised). That is
     * why we don't handle partial writes. Just pop the request
     * off the write queue and onto the completed queue, done.
     */
    QUEUE_REMOVE(&req->queue);
    QUEUE_INSERT_TAIL(&handle->write_completed_queue, &req->queue);
  }
}

static void loop_run_immediate(evLoop *loop) {
    QUEUE *q;
    evHandle *handle;
    while ( !QUEUE_EMPTY(&loop->handle_queue) ){
        q = QUEUE_HEAD(&(loop)->handle_queue);
        QUEUE_REMOVE(q);
        handle = QUEUE_DATA(q, evHandle, queue);
        assert(handle);
        handle->cb(handle);
    }
}

static Event queue_pop(Queue *queue)
{
  QUEUE *h = QUEUE_HEAD(&queue->headtail);
  queue_item *item = queue_node_data(h);
  QUEUE_REMOVE(&item->node);
  Event e;

  e = item->item;
  free(item);
  return e;
}

void uv_chan_clear(uv_chan_t *chan) {
    uv_mutex_lock(&chan->mutex);
    uv__chan_item_t *item = NULL;
    QUEUE *head = NULL;
    while (!QUEUE_EMPTY(&chan->q)) {
        head = QUEUE_HEAD(&chan->q);
        item = QUEUE_DATA(head, uv__chan_item_t, active_queue);
        QUEUE_REMOVE(head);
        free(item);
    }
    uv_mutex_unlock(&chan->mutex);
}