lib/libevent.c

/*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2010-2014 Andy Green <andy@warmcat.com>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation:
 *  version 2.1 of the License.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 *  MA  02110-1301  USA
 */

#include "private-libwebsockets.h"

void lws_feature_status_libevent(struct lws_context_creation_info *info)
{
  if (lws_check_opt(info->options, LWS_SERVER_OPTION_LIBEVENT))
    lwsl_notice("libevent support compiled in and enabled\n");
  else
    lwsl_notice("libevent support compiled in but disabled\n");
}

static void
lws_event_cb(evutil_socket_t sock_fd, short revents, void *ctx)
{
  struct lws_io_watcher *lws_io = (struct lws_io_watcher *)ctx;
  struct lws_context *context = lws_io->context;
  struct lws_pollfd eventfd;

  if (revents & EV_TIMEOUT)
    return;

  /* !!! EV_CLOSED doesn't exist in libevent2 */
#if LIBEVENT_VERSION_NUMBER < 0x02000000
  if (revents & EV_CLOSED)
  {
    event_del(lws_io->event_watcher);
    event_free(lws_io->event_watcher);
    return;
  }
#endif

  eventfd.fd = sock_fd;
  eventfd.events = 0;
  eventfd.revents = 0;
  if (revents & EV_READ)
  {
    eventfd.events |= LWS_POLLIN;
    eventfd.revents |= LWS_POLLIN;
  }
  if (revents & EV_WRITE)
  {
    eventfd.events |= LWS_POLLOUT;
    eventfd.revents |= LWS_POLLOUT;
  }
  lws_service_fd(context, &eventfd);
}

LWS_VISIBLE void
lws_event_sigint_cb(evutil_socket_t sock_fd, short revents, void *ctx)
{
  struct lws_context_per_thread *pt = ctx;
  if (!pt->ev_loop_foreign)
    event_base_loopbreak(pt->io_loop_event_base);
}

LWS_VISIBLE int
lws_event_sigint_cfg(struct lws_context *context, int use_event_sigint,
      lws_event_signal_cb_t *cb)
{
  context->use_ev_sigint = use_event_sigint;
  if (cb)
    context->lws_event_sigint_cb = cb;
  else
    context->lws_event_sigint_cb = &lws_event_sigint_cb;

  return 0;
}

LWS_VISIBLE int
lws_event_initloop(struct lws_context *context, struct event_base *loop,
    int tsi)
{
  if (!loop)
  {
    context->pt[tsi].io_loop_event_base = event_base_new();
  }
  else
  {
    context->pt[tsi].ev_loop_foreign = 1;
    context->pt[tsi].io_loop_event_base = loop;
  }

  /*
   * Initialize all events with the listening sockets
   * and register a callback for read operations
   */
  struct lws_vhost *vh = context->vhost_list;
  while (vh)
  {
    if (vh->lserv_wsi)
    {
      vh->lserv_wsi->w_read.context = context;
      vh->lserv_wsi->w_read.event_watcher = event_new(
          loop,
          vh->lserv_wsi->desc.sockfd,
          (EV_READ | EV_PERSIST),
          lws_event_cb,
          &vh->lserv_wsi->w_read);
      event_add(vh->lserv_wsi->w_read.event_watcher, NULL);
    }
    vh = vh->vhost_next;
  }

  /* Register the signal watcher unless the user says not to */
  if (context->use_ev_sigint)
  {
    struct event *w_sigint = evsignal_new(loop, SIGINT,
        context->lws_event_sigint_cb, &context->pt[tsi]);
    context->pt[tsi].w_sigint.event_watcher = w_sigint;
    event_add(w_sigint, NULL);
  }

  return 0;
}

void
lws_libevent_destroyloop(struct lws_context *context, int tsi)
{
  if (!lws_check_opt(context->options, LWS_SERVER_OPTION_LIBEVENT))
    return;

  struct lws_context_per_thread *pt = &context->pt[tsi];
  if (!pt->io_loop_event_base)
    return;

  /*
   * Free all events with the listening sockets
   */
  struct lws_vhost *vh = context->vhost_list;
  while (vh)
  {
    if (vh->lserv_wsi)
    {
      event_free(vh->lserv_wsi->w_read.event_watcher);
      vh->lserv_wsi->w_read.event_watcher = NULL;
    }
    vh = vh->vhost_next;
  }

  if (context->use_ev_sigint)
    event_free(pt->w_sigint.event_watcher);
  if (!pt->ev_loop_foreign)
    event_base_free(pt->io_loop_event_base);
}

LWS_VISIBLE void
lws_libevent_accept(struct lws *new_wsi, lws_sock_file_fd_type desc)
{
  struct lws_context *context = lws_get_context(new_wsi);
  if (!LWS_LIBEVENT_ENABLED(context))
    return;

  new_wsi->w_read.context = context;
  new_wsi->w_write.context = context;

  // Initialize the event
  struct lws_context_per_thread *pt = &context->pt[(int)new_wsi->tsi];
  int fd;
  if (new_wsi->mode == LWSCM_RAW_FILEDESC)
    fd = desc.filefd;
  else
    fd = desc.sockfd;
  new_wsi->w_read.event_watcher = event_new(pt->io_loop_event_base, fd,
      (EV_READ | EV_PERSIST), lws_event_cb, &new_wsi->w_read);
  new_wsi->w_write.event_watcher = event_new(pt->io_loop_event_base, fd,
      (EV_WRITE | EV_PERSIST), lws_event_cb, &new_wsi->w_write);
}

LWS_VISIBLE void
lws_libevent_io(struct lws *wsi, int flags)
{
  struct lws_context *context = lws_get_context(wsi);

  if (!LWS_LIBEVENT_ENABLED(context))
    return;

  struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
  if (!pt->io_loop_event_base || context->being_destroyed)
    return;

  assert((flags & (LWS_EV_START | LWS_EV_STOP)) &&
         (flags & (LWS_EV_READ | LWS_EV_WRITE)));

  if (flags & LWS_EV_START)
  {
    if (flags & LWS_EV_WRITE)
    {
      event_add(wsi->w_write.event_watcher, NULL);
    }
    if (flags & LWS_EV_READ)
    {
      event_add(wsi->w_read.event_watcher, NULL);
    }
  }
  else
  {
    if (flags & LWS_EV_WRITE)
    {
      event_del(wsi->w_write.event_watcher);
    }
    if (flags & LWS_EV_READ)
    {
      event_del(wsi->w_read.event_watcher);
    }
  }
}

LWS_VISIBLE int
lws_libevent_init_fd_table(struct lws_context *context)
{
  if (!LWS_LIBEVENT_ENABLED(context))
    return 0;

  int n;
  for (n = 0; n < context->count_threads; n++)
  {
    context->pt[n].w_sigint.context = context;
  }

  return 1;
}

LWS_VISIBLE void
lws_libevent_run(const struct lws_context *context, int tsi)
{
  // Run/Dispatch the event_base loop
  if (context->pt[tsi].io_loop_event_base && LWS_LIBEVENT_ENABLED(context))
    event_base_dispatch(context->pt[tsi].io_loop_event_base);
}