/src/libevent/event.c

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/*
 * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
 * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include "event2/event-config.h"
#include "evconfig-private.h"

#ifdef _WIN32
#include <winsock2.h>
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#undef WIN32_LEAN_AND_MEAN
#endif
#include <sys/types.h>
#if !defined(_WIN32) && defined(EVENT__HAVE_SYS_TIME_H)
#include <sys/time.h>
#endif
#include <sys/queue.h>
#ifdef EVENT__HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#ifdef EVENT__HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <ctype.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <time.h>
#include <limits.h>
#ifdef EVENT__HAVE_FCNTL_H
#include <fcntl.h>
#endif

#include "event2/event.h"
#include "event2/event_struct.h"
#include "event2/event_compat.h"
#include "event2/watch.h"
#include "event-internal.h"
#include "defer-internal.h"
#include "evthread-internal.h"
#include "event2/thread.h"
#include "event2/util.h"
#include "log-internal.h"
#include "evmap-internal.h"
#include "iocp-internal.h"
#include "changelist-internal.h"
#define HT_NO_CACHE_HASH_VALUES
#include "ht-internal.h"
#include "util-internal.h"


#ifdef EVENT__HAVE_WORKING_KQUEUE
#include "kqueue-internal.h"
#endif

#ifdef EVENT__HAVE_EVENT_PORTS
extern const struct eventop evportops;
#endif
#ifdef EVENT__HAVE_SELECT
extern const struct eventop selectops;
#endif
#ifdef EVENT__HAVE_POLL
extern const struct eventop pollops;
#endif
#ifdef EVENT__HAVE_EPOLL
extern const struct eventop epollops;
#endif
#ifdef EVENT__HAVE_WORKING_KQUEUE
extern const struct eventop kqops;
#endif
#ifdef EVENT__HAVE_DEVPOLL
extern const struct eventop devpollops;
#endif
#ifdef EVENT__HAVE_WEPOLL
extern const struct eventop wepollops;
#endif
#ifdef _WIN32
extern const struct eventop win32ops;
#endif

/* Array of backends in order of preference. */
static const struct eventop *eventops[] = {
#ifdef EVENT__HAVE_EVENT_PORTS
  &evportops,
#endif
#ifdef EVENT__HAVE_WORKING_KQUEUE
  &kqops,
#endif
#ifdef EVENT__HAVE_EPOLL
  &epollops,
#endif
#ifdef EVENT__HAVE_DEVPOLL
  &devpollops,
#endif
#ifdef EVENT__HAVE_POLL
  &pollops,
#endif
#ifdef EVENT__HAVE_SELECT
  &selectops,
#endif
#ifdef _WIN32
  &win32ops,
#endif
#ifdef EVENT__HAVE_WEPOLL
  &wepollops,
#endif
  NULL
};

/* Global state; deprecated */
EVENT2_EXPORT_SYMBOL
struct event_base *event_global_current_base_ = NULL;
#define current_base event_global_current_base_

/* Global state */

static void *event_self_cbarg_ptr_ = NULL;

/* Prototypes */
static void event_queue_insert_active(struct event_base *, struct event_callback *);
static void event_queue_insert_active_later(struct event_base *, struct event_callback *);
static void event_queue_insert_timeout(struct event_base *, struct event *);
static void event_queue_insert_inserted(struct event_base *, struct event *);
static void event_queue_remove_active(struct event_base *, struct event_callback *);
static void event_queue_remove_active_later(struct event_base *, struct event_callback *);
static void event_queue_remove_timeout(struct event_base *, struct event *);
static void event_queue_remove_inserted(struct event_base *, struct event *);
static void event_queue_make_later_events_active(struct event_base *base);

static int evthread_make_base_notifiable_nolock_(struct event_base *base);
static int event_del_(struct event *ev, int blocking);

#ifdef USE_REINSERT_TIMEOUT
/* This code seems buggy; only turn it on if we find out what the trouble is. */
static void event_queue_reinsert_timeout(struct event_base *,struct event *, int was_common, int is_common, int old_timeout_idx);
#endif

static int  event_haveevents(struct event_base *);

static int  event_process_active(struct event_base *);

static int  timeout_next(struct event_base *, struct timeval **);
static void timeout_process(struct event_base *);

static inline void  event_signal_closure(struct event_base *, struct event *ev);
static inline void  event_persist_closure(struct event_base *, struct event *ev);

static int  evthread_notify_base(struct event_base *base);

static void insert_common_timeout_inorder(struct common_timeout_list *ctl,
    struct event *ev);

#ifndef EVENT__DISABLE_DEBUG_MODE
/* These functions implement a hashtable of which 'struct event *' structures
 * have been setup or added.  We don't want to trust the content of the struct
 * event itself, since we're trying to work through cases where an event gets
 * clobbered or freed.  Instead, we keep a hashtable indexed by the pointer.
 */

struct event_debug_entry {
  HT_ENTRY(event_debug_entry) node;
  const struct event *ptr;
  unsigned added : 1;
};

static inline unsigned
hash_debug_entry(const struct event_debug_entry *e)
{
  /* We need to do this silliness to convince compilers that we
   * honestly mean to cast e->ptr to an integer, and discard any
   * part of it that doesn't fit in an unsigned.
   */
  unsigned u = (unsigned) ((ev_uintptr_t) e->ptr);
  /* Our hashtable implementation is pretty sensitive to low bits,
   * and every struct event is over 64 bytes in size, so we can
   * just say >>6. */
  return (u >> 6);
}

static inline int
eq_debug_entry(const struct event_debug_entry *a,
    const struct event_debug_entry *b)
{
  return a->ptr == b->ptr;
}

int event_debug_mode_on_ = 0;


#if !defined(EVENT__DISABLE_THREAD_SUPPORT) && !defined(EVENT__DISABLE_DEBUG_MODE)
/**
 * @brief debug mode variable which is set for any function/structure that needs
 *        to be shared across threads (if thread support is enabled).
 *
 *        When and if evthreads are initialized, this variable will be evaluated,
 *        and if set to something other than zero, this means the evthread setup
 *        functions were called out of order.
 *
 *        See: "Locks and threading" in the documentation.
 */
int event_debug_created_threadable_ctx_ = 0;
#endif

/* Set if it's too late to enable event_debug_mode. */
static int event_debug_mode_too_late = 0;
#ifndef EVENT__DISABLE_THREAD_SUPPORT
static void *event_debug_map_lock_ = NULL;
#endif
static HT_HEAD(event_debug_map, event_debug_entry) global_debug_map =
  HT_INITIALIZER();

HT_PROTOTYPE(event_debug_map, event_debug_entry, node, hash_debug_entry,
    eq_debug_entry)
HT_GENERATE(event_debug_map, event_debug_entry, node, hash_debug_entry,
    eq_debug_entry, 0.5, mm_malloc, mm_realloc, mm_free)

/* record that ev is now setup (that is, ready for an add) */
static void event_debug_note_setup_(const struct event *ev)
{
  struct event_debug_entry *dent, find;

  if (!event_debug_mode_on_)
    goto out;

  find.ptr = ev;
  EVLOCK_LOCK(event_debug_map_lock_, 0);
  dent = HT_FIND(event_debug_map, &global_debug_map, &find);
  if (dent) {
    dent->added = 0;
  } else {
    dent = mm_malloc(sizeof(*dent));
    if (!dent)
      event_err(1,
          "Out of memory in debugging code");
    dent->ptr = ev;
    dent->added = 0;
    HT_INSERT(event_debug_map, &global_debug_map, dent);
  }
  EVLOCK_UNLOCK(event_debug_map_lock_, 0);

out:
  event_debug_mode_too_late = 1;
}
/* record that ev is no longer setup */
static void event_debug_note_teardown_(const struct event *ev)
{
  struct event_debug_entry *dent, find;

  if (!event_debug_mode_on_)
    goto out;

  find.ptr = ev;
  EVLOCK_LOCK(event_debug_map_lock_, 0);
  dent = HT_REMOVE(event_debug_map, &global_debug_map, &find);
  if (dent)
    mm_free(dent);
  EVLOCK_UNLOCK(event_debug_map_lock_, 0);

out:
  event_debug_mode_too_late = 1;
}
/* Macro: record that ev is now added */
static void event_debug_note_add_(const struct event *ev)
{
  struct event_debug_entry *dent,find;

  if (!event_debug_mode_on_)
    goto out;

  find.ptr = ev;
  EVLOCK_LOCK(event_debug_map_lock_, 0);
  dent = HT_FIND(event_debug_map, &global_debug_map, &find);
  if (dent) {
    dent->added = 1;
  } else {
    event_errx(EVENT_ERR_ABORT_,
        "%s: noting an add on a non-setup event %p"
        " (events: 0x%x, fd: "EV_SOCK_FMT
        ", flags: 0x%x)",
        __func__, (void *)ev, ev->ev_events,
        EV_SOCK_ARG(ev->ev_fd), ev->ev_flags);
  }
  EVLOCK_UNLOCK(event_debug_map_lock_, 0);

out:
  event_debug_mode_too_late = 1;
}
/* record that ev is no longer added */
static void event_debug_note_del_(const struct event *ev)
{
  struct event_debug_entry *dent, find;

  if (!event_debug_mode_on_)
    goto out;

  find.ptr = ev;
  EVLOCK_LOCK(event_debug_map_lock_, 0);
  dent = HT_FIND(event_debug_map, &global_debug_map, &find);
  if (dent) {
    dent->added = 0;
  } else {
    event_errx(EVENT_ERR_ABORT_,
        "%s: noting a del on a non-setup event %p"
        " (events: 0x%x, fd: "EV_SOCK_FMT
        ", flags: 0x%x)",
        __func__, (void *)ev, ev->ev_events,
        EV_SOCK_ARG(ev->ev_fd), ev->ev_flags);
  }
  EVLOCK_UNLOCK(event_debug_map_lock_, 0);

out:
  event_debug_mode_too_late = 1;
}
/* assert that ev is setup (i.e., okay to add or inspect) */
static void event_debug_assert_is_setup_(const struct event *ev)
{
  struct event_debug_entry *dent, find;

  if (!event_debug_mode_on_)
    return;

  find.ptr = ev;
  EVLOCK_LOCK(event_debug_map_lock_, 0);
  dent = HT_FIND(event_debug_map, &global_debug_map, &find);
  if (!dent) {
    event_errx(EVENT_ERR_ABORT_,
        "%s called on a non-initialized event %p"
        " (events: 0x%x, fd: "EV_SOCK_FMT
        ", flags: 0x%x)",
        __func__, (void *)ev, ev->ev_events,
        EV_SOCK_ARG(ev->ev_fd), ev->ev_flags);
  }
  EVLOCK_UNLOCK(event_debug_map_lock_, 0);
}
/* assert that ev is not added (i.e., okay to tear down or set up again) */
static void event_debug_assert_not_added_(const struct event *ev)
{
  struct event_debug_entry *dent, find;

  if (!event_debug_mode_on_)
    return;

  find.ptr = ev;
  EVLOCK_LOCK(event_debug_map_lock_, 0);
  dent = HT_FIND(event_debug_map, &global_debug_map, &find);
  if (dent && dent->added) {
    event_errx(EVENT_ERR_ABORT_,
        "%s called on an already added event %p"
        " (events: 0x%x, fd: "EV_SOCK_FMT", "
        "flags: 0x%x)",
        __func__, (void *)ev, ev->ev_events,
        EV_SOCK_ARG(ev->ev_fd), ev->ev_flags);
  }
  EVLOCK_UNLOCK(event_debug_map_lock_, 0);
}
static void event_debug_assert_socket_nonblocking_(evutil_socket_t fd)
{
  if (!event_debug_mode_on_)
    return;
  if (fd < 0)
    return;

#ifndef _WIN32
  {
    int flags;
    if ((flags = fcntl(fd, F_GETFL, NULL)) >= 0) {
      EVUTIL_ASSERT(flags & O_NONBLOCK);
    }
  }
#endif
}
#else
static void event_debug_note_setup_(const struct event *ev) { (void)ev; }
static void event_debug_note_teardown_(const struct event *ev) { (void)ev; }
static void event_debug_note_add_(const struct event *ev) { (void)ev; }
static void event_debug_note_del_(const struct event *ev) { (void)ev; }
static void event_debug_assert_is_setup_(const struct event *ev) { (void)ev; }
static void event_debug_assert_not_added_(const struct event *ev) { (void)ev; }
static void event_debug_assert_socket_nonblocking_(evutil_socket_t fd) { (void)fd; }
#endif

#define EVENT_BASE_ASSERT_LOCKED(base)    \
  EVLOCK_ASSERT_LOCKED((base)->th_base_lock)

/* How often (in seconds) do we check for changes in wall clock time relative
 * to monotonic time?  Set this to -1 for 'never.' */
#define CLOCK_SYNC_INTERVAL -1

/** Set 'tp' to the current time according to 'base'.  We must hold the lock
 * on 'base'.  If there is a cached time, return it.  Otherwise, use
 * clock_gettime or gettimeofday as appropriate to find out the right time.
 * Return 0 on success, -1 on failure.
 */
static int
gettime(struct event_base *base, struct timeval *tp)
{
  EVENT_BASE_ASSERT_LOCKED(base);

  if (base->tv_cache.tv_sec) {
    *tp = base->tv_cache;
    return (0);
  }

  if (evutil_gettime_monotonic_(&base->monotonic_timer, tp) == -1) {
    return -1;
  }

  if (base->last_updated_clock_diff + CLOCK_SYNC_INTERVAL
      < tp->tv_sec) {
    struct timeval tv;
    evutil_gettimeofday(&tv,NULL);
    evutil_timersub(&tv, tp, &base->tv_clock_diff);
    base->last_updated_clock_diff = tp->tv_sec;
  }

  return 0;
}

int
event_base_gettimeofday_cached(struct event_base *base, struct timeval *tv)
{
  int r;
  if (!base) {
    base = current_base;
    if (!current_base)
      return evutil_gettimeofday(tv, NULL);
  }

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  if (base->tv_cache.tv_sec == 0) {
    r = evutil_gettimeofday(tv, NULL);
  } else {
    evutil_timeradd(&base->tv_cache, &base->tv_clock_diff, tv);
    r = 0;
  }
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return r;
}

/** Make 'base' have no current cached time. */
static inline void
clear_time_cache(struct event_base *base)
{
  base->tv_cache.tv_sec = 0;
}

/** Replace the cached time in 'base' with the current time. */
static inline void
update_time_cache(struct event_base *base)
{
  base->tv_cache.tv_sec = 0;
  if (!(base->flags & EVENT_BASE_FLAG_NO_CACHE_TIME))
    gettime(base, &base->tv_cache);
}

int
event_base_update_cache_time(struct event_base *base)
{

  if (!base) {
    base = current_base;
    if (!current_base)
      return -1;
  }

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  if (base->running_loop)
    update_time_cache(base);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return 0;
}

static inline struct event *
event_callback_to_event(struct event_callback *evcb)
{
  EVUTIL_ASSERT((evcb->evcb_flags & EVLIST_INIT));
  return EVUTIL_UPCAST(evcb, struct event, ev_evcallback);
}

static inline struct event_callback *
event_to_event_callback(struct event *ev)
{
  return &ev->ev_evcallback;
}

struct event_base *
event_init(void)
{
  struct event_base *base = event_base_new_with_config(NULL);

  if (base == NULL) {
    event_errx(1, "%s: Unable to construct event_base", __func__);
    return NULL;
  }

  current_base = base;

  return (base);
}

struct event_base *
event_base_new(void)
{
  struct event_base *base = NULL;
  struct event_config *cfg = event_config_new();
  if (cfg) {
    base = event_base_new_with_config(cfg);
    event_config_free(cfg);
  }
  return base;
}

/** Return true iff 'method' is the name of a method that 'cfg' tells us to
 * avoid. */
static int
event_config_is_avoided_method(const struct event_config *cfg,
    const char *method)
{
  struct event_config_entry *entry;

  TAILQ_FOREACH(entry, &cfg->entries, next) {
    if (entry->avoid_method != NULL &&
        strcmp(entry->avoid_method, method) == 0)
      return (1);
  }

  return (0);
}

/** Return true iff 'method' is disabled according to the environment. */
static int
event_is_method_disabled(const char *name)
{
  char environment[64];
  int i;

  evutil_snprintf(environment, sizeof(environment), "EVENT_NO%s", name);
  for (i = 8; environment[i] != '\0'; ++i)
    environment[i] = EVUTIL_TOUPPER_(environment[i]);
  /* Note that evutil_getenv_() ignores the environment entirely if
   * we're setuid */
  return (evutil_getenv_(environment) != NULL);
}

int
event_base_get_features(const struct event_base *base)
{
  return base->evsel->features;
}

void
event_enable_debug_mode(void)
{
#ifndef EVENT__DISABLE_DEBUG_MODE
  if (event_debug_mode_on_)
    event_errx(1, "%s was called twice!", __func__);
  if (event_debug_mode_too_late)
    event_errx(1, "%s must be called *before* creating any events "
        "or event_bases",__func__);

  event_debug_mode_on_ = 1;

  HT_INIT(event_debug_map, &global_debug_map);
#endif
}

void
event_disable_debug_mode(void)
{
#ifndef EVENT__DISABLE_DEBUG_MODE
  struct event_debug_entry **ent, *victim;

  EVLOCK_LOCK(event_debug_map_lock_, 0);
  for (ent = HT_START(event_debug_map, &global_debug_map); ent; ) {
    victim = *ent;
    ent = HT_NEXT_RMV(event_debug_map, &global_debug_map, ent);
    mm_free(victim);
  }
  HT_CLEAR(event_debug_map, &global_debug_map);
  EVLOCK_UNLOCK(event_debug_map_lock_ , 0);

  event_debug_mode_on_  = 0;
#endif
}

struct event_base *
event_base_new_with_config(const struct event_config *cfg)
{
  int i;
  struct event_base *base;
  int should_check_environment;

#ifndef EVENT__DISABLE_DEBUG_MODE
  event_debug_mode_too_late = 1;
#endif

  if ((base = mm_calloc(1, sizeof(struct event_base))) == NULL) {
    event_warn("%s: calloc", __func__);
    return NULL;
  }

  if (cfg)
    base->flags = cfg->flags;

  should_check_environment =
      !(cfg && (cfg->flags & EVENT_BASE_FLAG_IGNORE_ENV));

  {
    struct timeval tmp;
    int precise_time =
        cfg && (cfg->flags & EVENT_BASE_FLAG_PRECISE_TIMER);
    int flags;
    if (should_check_environment && !precise_time) {
      precise_time = evutil_getenv_("EVENT_PRECISE_TIMER") != NULL;
      if (precise_time) {
        base->flags |= EVENT_BASE_FLAG_PRECISE_TIMER;
      }
    }
    flags = precise_time ? EV_MONOT_PRECISE : 0;
    evutil_configure_monotonic_time_(&base->monotonic_timer, flags);

    gettime(base, &tmp);
  }

  min_heap_ctor_(&base->timeheap);

  base->sig.ev_signal_pair[0] = -1;
  base->sig.ev_signal_pair[1] = -1;
  base->th_notify_fd[0] = -1;
  base->th_notify_fd[1] = -1;

  TAILQ_INIT(&base->active_later_queue);

  evmap_io_initmap_(&base->io);
  evmap_signal_initmap_(&base->sigmap);
  event_changelist_init_(&base->changelist);

  base->evbase = NULL;

  if (cfg) {
    memcpy(&base->max_dispatch_time,
        &cfg->max_dispatch_interval, sizeof(struct timeval));
    base->limit_callbacks_after_prio =
        cfg->limit_callbacks_after_prio;
  } else {
    base->max_dispatch_time.tv_sec = -1;
    base->limit_callbacks_after_prio = 1;
  }
  if (cfg && cfg->max_dispatch_callbacks >= 0) {
    base->max_dispatch_callbacks = cfg->max_dispatch_callbacks;
  } else {
    base->max_dispatch_callbacks = INT_MAX;
  }
  if (base->max_dispatch_callbacks == INT_MAX &&
      base->max_dispatch_time.tv_sec == -1)
    base->limit_callbacks_after_prio = INT_MAX;

  for (i = 0; eventops[i] && !base->evbase; i++) {
    if (cfg != NULL) {
      /* determine if this backend should be avoided */
      if (event_config_is_avoided_method(cfg,
        eventops[i]->name))
        continue;
      if ((eventops[i]->features & cfg->require_features)
          != cfg->require_features)
        continue;
    }

    /* also obey the environment variables */
    if (should_check_environment &&
        event_is_method_disabled(eventops[i]->name))
      continue;

    base->evsel = eventops[i];

    base->evbase = base->evsel->init(base);
  }

  if (base->evbase == NULL) {
    event_warnx("%s: no event mechanism available",
        __func__);
    base->evsel = NULL;
    event_base_free(base);
    return NULL;
  }

  if (evutil_getenv_("EVENT_SHOW_METHOD"))
    event_msgx("libevent using: %s", base->evsel->name);

  /* allocate a single active event queue */
  if (event_base_priority_init(base, 1) < 0) {
    event_base_free(base);
    return NULL;
  }

  /* prepare for threading */

#if !defined(EVENT__DISABLE_THREAD_SUPPORT) && !defined(EVENT__DISABLE_DEBUG_MODE)
  event_debug_created_threadable_ctx_ = 1;
#endif

#ifndef EVENT__DISABLE_THREAD_SUPPORT
  if (EVTHREAD_LOCKING_ENABLED() &&
      (!cfg || !(cfg->flags & EVENT_BASE_FLAG_NOLOCK))) {
    int r;
    EVTHREAD_ALLOC_LOCK(base->th_base_lock, 0);
    EVTHREAD_ALLOC_COND(base->current_event_cond);
    r = evthread_make_base_notifiable(base);
    if (r<0) {
      event_warnx("%s: Unable to make base notifiable.", __func__);
      event_base_free(base);
      return NULL;
    }
  }
#endif

#ifdef _WIN32
  if (cfg && (cfg->flags & EVENT_BASE_FLAG_STARTUP_IOCP))
    event_base_start_iocp_(base, cfg->n_cpus_hint);
#endif

  /* initialize watcher lists */
  for (i = 0; i < EVWATCH_MAX; ++i)
    TAILQ_INIT(&base->watchers[i]);

  return (base);
}

int
event_base_start_iocp_(struct event_base *base, int n_cpus)
{
#ifdef _WIN32
  if (base->iocp)
    return 0;
  base->iocp = event_iocp_port_launch_(n_cpus);
  if (!base->iocp) {
    event_warnx("%s: Couldn't launch IOCP", __func__);
    return -1;
  }
  return 0;
#else
  return -1;
#endif
}

void
event_base_stop_iocp_(struct event_base *base)
{
#ifdef _WIN32
  int rv;

  if (!base->iocp)
    return;
  rv = event_iocp_shutdown_(base->iocp, -1);
  EVUTIL_ASSERT(rv >= 0);
  base->iocp = NULL;
#endif
}

static int
event_base_cancel_single_callback_(struct event_base *base,
    struct event_callback *evcb,
    int run_finalizers)
{
  int result = 0;

  if (evcb->evcb_flags & EVLIST_INIT) {
    struct event *ev = event_callback_to_event(evcb);
    if (!(ev->ev_flags & EVLIST_INTERNAL)) {
      event_del_(ev, EVENT_DEL_EVEN_IF_FINALIZING);
      result = 1;
    }
  } else {
    EVBASE_ACQUIRE_LOCK(base, th_base_lock);
    event_callback_cancel_nolock_(base, evcb, 1);
    EVBASE_RELEASE_LOCK(base, th_base_lock);
    result = 1;
  }

  if (run_finalizers && (evcb->evcb_flags & EVLIST_FINALIZING)) {
    switch (evcb->evcb_closure) {
    case EV_CLOSURE_EVENT_FINALIZE:
    case EV_CLOSURE_EVENT_FINALIZE_FREE: {
      struct event *ev = event_callback_to_event(evcb);
      ev->ev_evcallback.evcb_cb_union.evcb_evfinalize(ev, ev->ev_arg);
      if (evcb->evcb_closure == EV_CLOSURE_EVENT_FINALIZE_FREE)
        mm_free(ev);
      break;
    }
    case EV_CLOSURE_CB_FINALIZE:
      evcb->evcb_cb_union.evcb_cbfinalize(evcb, evcb->evcb_arg);
      break;
    default:
      break;
    }
  }
  return result;
}

static int event_base_free_queues_(struct event_base *base, int run_finalizers)
{
  int deleted = 0, i;

  for (i = 0; i < base->nactivequeues; ++i) {
    struct event_callback *evcb, *next;
    for (evcb = TAILQ_FIRST(&base->activequeues[i]); evcb; ) {
      next = TAILQ_NEXT(evcb, evcb_active_next);
      deleted += event_base_cancel_single_callback_(base, evcb, run_finalizers);
      evcb = next;
    }
  }

  {
    struct event_callback *evcb;
    while ((evcb = TAILQ_FIRST(&base->active_later_queue))) {
      deleted += event_base_cancel_single_callback_(base, evcb, run_finalizers);
    }
  }

  return deleted;
}

static void
event_base_free_(struct event_base *base, int run_finalizers)
{
  int i;
  size_t n_deleted=0;
  struct event *ev;
  struct evwatch *watcher;
  /* XXXX grab the lock? If there is contention when one thread frees
   * the base, then the contending thread will be very sad soon. */

  /* event_base_free(NULL) is how to free the current_base if we
   * made it with event_init and forgot to hold a reference to it. */
  if (base == NULL && current_base)
    base = current_base;
  /* Don't actually free NULL. */
  if (base == NULL) {
    event_warnx("%s: no base to free", __func__);
    return;
  }
  /* XXX(niels) - check for internal events first */

#ifdef _WIN32
  event_base_stop_iocp_(base);
#endif

  /* threading fds if we have them */
  if (base->th_notify_fd[0] != -1) {
    event_del(&base->th_notify);
    EVUTIL_CLOSESOCKET(base->th_notify_fd[0]);
    if (base->th_notify_fd[1] != -1)
      EVUTIL_CLOSESOCKET(base->th_notify_fd[1]);
    base->th_notify_fd[0] = -1;
    base->th_notify_fd[1] = -1;
    event_debug_unassign(&base->th_notify);
  }

  /* Delete all non-internal events. */
  evmap_delete_all_(base);

  while ((ev = min_heap_top_(&base->timeheap)) != NULL) {
    event_del(ev);
    ++n_deleted;
  }
  for (i = 0; i < base->n_common_timeouts; ++i) {
    struct common_timeout_list *ctl =
        base->common_timeout_queues[i];
    event_del(&ctl->timeout_event); /* Internal; doesn't count */
    event_debug_unassign(&ctl->timeout_event);
    for (ev = TAILQ_FIRST(&ctl->events); ev; ) {
      struct event *next = TAILQ_NEXT(ev,
          ev_timeout_pos.ev_next_with_common_timeout);
      if (!(ev->ev_flags & EVLIST_INTERNAL)) {
        event_del(ev);
        ++n_deleted;
      }
      ev = next;
    }
    mm_free(ctl);
  }
  if (base->common_timeout_queues)
    mm_free(base->common_timeout_queues);

  for (;;) {
    /* For finalizers we can register yet another finalizer out from
     * finalizer, and iff finalizer will be in active_later_queue we can
     * add finalizer to activequeues, and we will have events in
     * activequeues after this function returns, which is not what we want
     * (we even have an assertion for this).
     *
     * A simple case is bufferevent with underlying (i.e. filters).
     */
    int i = event_base_free_queues_(base, run_finalizers);
    event_debug(("%s: %d events freed", __func__, i));
    if (!i) {
      break;
    }
    n_deleted += i;
  }

  if (n_deleted)
    event_debug(("%s: "EV_SIZE_FMT" events were still set in base",
      __func__, n_deleted));

  while (LIST_FIRST(&base->once_events)) {
    struct event_once *eonce = LIST_FIRST(&base->once_events);
    LIST_REMOVE(eonce, next_once);
    mm_free(eonce);
  }

  if (base->evsel != NULL && base->evsel->dealloc != NULL)
    base->evsel->dealloc(base);

  for (i = 0; i < base->nactivequeues; ++i)
    EVUTIL_ASSERT(TAILQ_EMPTY(&base->activequeues[i]));

  EVUTIL_ASSERT(min_heap_empty_(&base->timeheap));
  min_heap_dtor_(&base->timeheap);

  mm_free(base->activequeues);

  evmap_io_clear_(&base->io);
  evmap_signal_clear_(&base->sigmap);
  event_changelist_freemem_(&base->changelist);

  EVTHREAD_FREE_LOCK(base->th_base_lock, 0);
  EVTHREAD_FREE_COND(base->current_event_cond);

  /* Free all event watchers */
  for (i = 0; i < EVWATCH_MAX; ++i) {
    while (!TAILQ_EMPTY(&base->watchers[i])) {
      watcher = TAILQ_FIRST(&base->watchers[i]);
      TAILQ_REMOVE(&base->watchers[i], watcher, next);
      mm_free(watcher);
    }
  }

  /* If we're freeing current_base, there won't be a current_base. */
  if (base == current_base)
    current_base = NULL;
  mm_free(base);
}

void
event_base_free_nofinalize(struct event_base *base)
{
  event_base_free_(base, 0);
}

void
event_base_free(struct event_base *base)
{
  event_base_free_(base, 1);
}

/* Fake eventop; used to disable the backend temporarily inside event_reinit
 * so that we can call event_del() on an event without telling the backend.
 */
static int
nil_backend_del(struct event_base *b, evutil_socket_t fd, short old,
    short events, void *fdinfo)
{
  return 0;
}
const struct eventop nil_eventop = {
  "nil",
  NULL, /* init: unused. */
  NULL, /* add: unused. */
  nil_backend_del, /* del: used, so needs to be killed. */
  NULL, /* dispatch: unused. */
  NULL, /* dealloc: unused. */
  0, 0, 0
};

/* reinitialize the event base after a fork */
int
event_reinit(struct event_base *base)
{
  const struct eventop *evsel;
  int res = 0;
  int was_notifiable = 0;
  int had_signal_added = 0;

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);

  evsel = base->evsel;

  /* check if this event mechanism requires reinit on the backend */
  if (evsel->need_reinit) {
    /* We're going to call event_del() on our notify events (the
     * ones that tell about signals and wakeup events).  But we
     * don't actually want to tell the backend to change its
     * state, since it might still share some resource (a kqueue,
     * an epoll fd) with the parent process, and we don't want to
     * delete the fds from _that_ backend, we temporarily stub out
     * the evsel with a replacement.
     */
    base->evsel = &nil_eventop;
  }

  /* We need to re-create a new signal-notification fd and a new
   * thread-notification fd.  Otherwise, we'll still share those with
   * the parent process, which would make any notification sent to them
   * get received by one or both of the event loops, more or less at
   * random.
   */
  if (base->sig.ev_signal_added) {
    event_del_nolock_(&base->sig.ev_signal, EVENT_DEL_AUTOBLOCK);
    event_debug_unassign(&base->sig.ev_signal);
    memset(&base->sig.ev_signal, 0, sizeof(base->sig.ev_signal));
    had_signal_added = 1;
    base->sig.ev_signal_added = 0;
  }
  if (base->sig.ev_signal_pair[0] != -1)
    EVUTIL_CLOSESOCKET(base->sig.ev_signal_pair[0]);
  if (base->sig.ev_signal_pair[1] != -1)
    EVUTIL_CLOSESOCKET(base->sig.ev_signal_pair[1]);
  if (base->th_notify_fn != NULL) {
    was_notifiable = 1;
    base->th_notify_fn = NULL;
  }
  if (base->th_notify_fd[0] != -1) {
    event_del_nolock_(&base->th_notify, EVENT_DEL_AUTOBLOCK);
    EVUTIL_CLOSESOCKET(base->th_notify_fd[0]);
    if (base->th_notify_fd[1] != -1)
      EVUTIL_CLOSESOCKET(base->th_notify_fd[1]);
    base->th_notify_fd[0] = -1;
    base->th_notify_fd[1] = -1;
    event_debug_unassign(&base->th_notify);
  }

  /* Replace the original evsel. */
        base->evsel = evsel;

  if (evsel->need_reinit) {
    /* Reconstruct the backend through brute-force, so that we do
     * not share any structures with the parent process. For some
     * backends, this is necessary: epoll and kqueue, for
     * instance, have events associated with a kernel
     * structure. If didn't reinitialize, we'd share that
     * structure with the parent process, and any changes made by
     * the parent would affect our backend's behavior (and vice
     * versa).
     */
    if (base->evsel->dealloc != NULL)
      base->evsel->dealloc(base);
    base->evbase = evsel->init(base);
    if (base->evbase == NULL) {
      event_errx(1,
         "%s: could not reinitialize event mechanism",
         __func__);
      res = -1;
      goto done;
    }

    /* Empty out the changelist (if any): we are starting from a
     * blank slate. */
    event_changelist_freemem_(&base->changelist);

    /* Tell the event maps to re-inform the backend about all
     * pending events. This will make the signal notification
     * event get re-created if necessary. */
    if (evmap_reinit_(base) < 0)
      res = -1;
  } else {
    res = evsig_init_(base);
    if (res == 0 && had_signal_added) {
      res = event_add_nolock_(&base->sig.ev_signal, NULL, 0);
      if (res == 0)
        base->sig.ev_signal_added = 1;
    }
  }

  /* If we were notifiable before, and nothing just exploded, become
   * notifiable again. */
  if (was_notifiable && res == 0)
    res = evthread_make_base_notifiable_nolock_(base);

done:
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return (res);
}

/* Get the monotonic time for this event_base' timer */
int
event_gettime_monotonic(struct event_base *base, struct timeval *tv)
{
  int rv = -1;

  if (base && tv) {
    EVBASE_ACQUIRE_LOCK(base, th_base_lock);
    rv = evutil_gettime_monotonic_(&(base->monotonic_timer), tv);
    EVBASE_RELEASE_LOCK(base, th_base_lock);
  }

  return rv;
}

const char **
event_get_supported_methods(void)
{
  static const char **methods = NULL;
  const struct eventop **method;
  const char **tmp;
  int i = 0, k;

  /* count all methods */
  for (method = &eventops[0]; *method != NULL; ++method) {
    ++i;
  }

  /* allocate one more than we need for the NULL pointer */
  tmp = mm_calloc((i + 1), sizeof(char *));
  if (tmp == NULL)
    return (NULL);

  /* populate the array with the supported methods */
  for (k = 0, i = 0; eventops[k] != NULL; ++k) {
    tmp[i++] = eventops[k]->name;
  }
  tmp[i] = NULL;

  if (methods != NULL)
    mm_free((char**)methods);

  methods = tmp;

  return (methods);
}

struct event_config *
event_config_new(void)
{
  struct event_config *cfg = mm_calloc(1, sizeof(*cfg));

  if (cfg == NULL)
    return (NULL);

  TAILQ_INIT(&cfg->entries);
  cfg->max_dispatch_interval.tv_sec = -1;
  cfg->max_dispatch_callbacks = INT_MAX;
  cfg->limit_callbacks_after_prio = 1;

  return (cfg);
}

static void
event_config_entry_free(struct event_config_entry *entry)
{
  if (entry->avoid_method != NULL)
    mm_free((char *)entry->avoid_method);
  mm_free(entry);
}

void
event_config_free(struct event_config *cfg)
{
  struct event_config_entry *entry;

  while ((entry = TAILQ_FIRST(&cfg->entries)) != NULL) {
    TAILQ_REMOVE(&cfg->entries, entry, next);
    event_config_entry_free(entry);
  }
  mm_free(cfg);
}

int
event_config_set_flag(struct event_config *cfg, int flag)
{
  if (!cfg)
    return -1;
  cfg->flags |= flag;
  return 0;
}

int
event_config_avoid_method(struct event_config *cfg, const char *method)
{
  struct event_config_entry *entry = mm_malloc(sizeof(*entry));
  if (entry == NULL)
    return (-1);

  if ((entry->avoid_method = mm_strdup(method)) == NULL) {
    mm_free(entry);
    return (-1);
  }

  TAILQ_INSERT_TAIL(&cfg->entries, entry, next);

  return (0);
}

int
event_config_require_features(struct event_config *cfg,
    int features)
{
  if (!cfg)
    return (-1);
  cfg->require_features = features;
  return (0);
}

int
event_config_set_num_cpus_hint(struct event_config *cfg, int cpus)
{
  if (!cfg)
    return (-1);
  cfg->n_cpus_hint = cpus;
  return (0);
}

int
event_config_set_max_dispatch_interval(struct event_config *cfg,
    const struct timeval *max_interval, int max_callbacks, int min_priority)
{
  if (max_interval)
    memcpy(&cfg->max_dispatch_interval, max_interval,
        sizeof(struct timeval));
  else
    cfg->max_dispatch_interval.tv_sec = -1;
  cfg->max_dispatch_callbacks =
      max_callbacks >= 0 ? max_callbacks : INT_MAX;
  if (min_priority < 0)
    min_priority = 0;
  cfg->limit_callbacks_after_prio = min_priority;
  return (0);
}

int
event_priority_init(int npriorities)
{
  return event_base_priority_init(current_base, npriorities);
}

int
event_base_priority_init(struct event_base *base, int npriorities)
{
  int i, r;
  r = -1;

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);

  if (N_ACTIVE_CALLBACKS(base) || npriorities < 1
      || npriorities >= EVENT_MAX_PRIORITIES)
    goto err;

  if (npriorities == base->nactivequeues)
    goto ok;

  if (base->nactivequeues) {
    mm_free(base->activequeues);
    base->nactivequeues = 0;
  }

  /* Allocate our priority queues */
  base->activequeues = (struct evcallback_list *)
    mm_calloc(npriorities, sizeof(struct evcallback_list));
  if (base->activequeues == NULL) {
    event_warn("%s: calloc", __func__);
    goto err;
  }
  base->nactivequeues = npriorities;

  for (i = 0; i < base->nactivequeues; ++i) {
    TAILQ_INIT(&base->activequeues[i]);
  }

ok:
  r = 0;
err:
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return (r);
}

int
event_base_get_npriorities(struct event_base *base)
{

  int n;
  if (base == NULL)
    base = current_base;

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  n = base->nactivequeues;
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return (n);
}

int
event_base_get_num_events(struct event_base *base, unsigned int type)
{
  int r = 0;

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);

  if (type & EVENT_BASE_COUNT_ACTIVE)
    r += base->event_count_active;

  if (type & EVENT_BASE_COUNT_VIRTUAL)
    r += base->virtual_event_count;

  if (type & EVENT_BASE_COUNT_ADDED)
    r += base->event_count;

  EVBASE_RELEASE_LOCK(base, th_base_lock);

  return r;
}

int
event_base_get_max_events(struct event_base *base, unsigned int type, int clear)
{
  int r = 0;

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);

  if (type & EVENT_BASE_COUNT_ACTIVE) {
    r += base->event_count_active_max;
    if (clear)
      base->event_count_active_max = 0;
  }

  if (type & EVENT_BASE_COUNT_VIRTUAL) {
    r += base->virtual_event_count_max;
    if (clear)
      base->virtual_event_count_max = 0;
  }

  if (type & EVENT_BASE_COUNT_ADDED) {
    r += base->event_count_max;
    if (clear)
      base->event_count_max = 0;
  }

  EVBASE_RELEASE_LOCK(base, th_base_lock);

  return r;
}

/* Returns true iff we're currently watching any events. */
static int
event_haveevents(struct event_base *base)
{
  /* Caller must hold th_base_lock */
  return (base->virtual_event_count > 0 || base->event_count > 0);
}

/* "closure" function called when processing active signal events */
static inline void
event_signal_closure(struct event_base *base, struct event *ev)
{
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic push
/* NOTE: it is better to avoid such code all together, by using separate
 * variable to break the loop in the event structure, but now this code is safe
 * */
#pragma GCC diagnostic ignored "-Wdangling-pointer"
#endif

  short ncalls;
  int should_break;

  /* Allows deletes to work, see also event_del_nolock_() that has
   * special treatment for signals */
  ncalls = ev->ev_ncalls;
  if (ncalls != 0)
    ev->ev_pncalls = &ncalls;
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  while (ncalls) {
    ncalls--;
    ev->ev_ncalls = ncalls;
    if (ncalls == 0)
      ev->ev_pncalls = NULL;
    (*ev->ev_callback)(ev->ev_fd, ev->ev_res, ev->ev_arg);

    EVBASE_ACQUIRE_LOCK(base, th_base_lock);
    should_break = base->event_break;
    EVBASE_RELEASE_LOCK(base, th_base_lock);

    if (should_break) {
      if (ncalls != 0)
        ev->ev_pncalls = NULL;
      return;
    }
  }

#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic pop
#endif
}

/* Common timeouts are special timeouts that are handled as queues rather than
 * in the minheap.  This is more efficient than the minheap if we happen to
 * know that we're going to get several thousands of timeout events all with
 * the same timeout value.
 *
 * Since all our timeout handling code assumes timevals can be copied,
 * assigned, etc, we can't use "magic pointer" to encode these common
 * timeouts.  Searching through a list to see if every timeout is common could
 * also get inefficient.  Instead, we take advantage of the fact that tv_usec
 * is 32 bits long, but only uses 20 of those bits (since it can never be over
 * 999999.)  We use the top bits to encode 4 bites of magic number, and 8 bits
 * of index into the event_base's aray of common timeouts.
 */

#define MICROSECONDS_MASK       COMMON_TIMEOUT_MICROSECONDS_MASK
#define COMMON_TIMEOUT_IDX_MASK 0x0ff00000
#define COMMON_TIMEOUT_IDX_SHIFT 20
#define COMMON_TIMEOUT_MASK     0xf0000000
#define COMMON_TIMEOUT_MAGIC    0x50000000

#define COMMON_TIMEOUT_IDX(tv) \
  (((tv)->tv_usec & COMMON_TIMEOUT_IDX_MASK)>>COMMON_TIMEOUT_IDX_SHIFT)

/** Return true iff if 'tv' is a common timeout in 'base' */
static inline int
is_common_timeout(const struct timeval *tv,
    const struct event_base *base)
{
  int idx;
  if ((tv->tv_usec & COMMON_TIMEOUT_MASK) != COMMON_TIMEOUT_MAGIC)
    return 0;
  idx = COMMON_TIMEOUT_IDX(tv);
  return idx < base->n_common_timeouts;
}

/* True iff tv1 and tv2 have the same common-timeout index, or if neither
 * one is a common timeout. */
static inline int
is_same_common_timeout(const struct timeval *tv1, const struct timeval *tv2)
{
  return (tv1->tv_usec & ~MICROSECONDS_MASK) ==
      (tv2->tv_usec & ~MICROSECONDS_MASK);
}

/** Requires that 'tv' is a common timeout.  Return the corresponding
 * common_timeout_list. */
static inline struct common_timeout_list *
get_common_timeout_list(struct event_base *base, const struct timeval *tv)
{
  return base->common_timeout_queues[COMMON_TIMEOUT_IDX(tv)];
}

#if 0
static inline int
common_timeout_ok(const struct timeval *tv,
    struct event_base *base)
{
  const struct timeval *expect =
      &get_common_timeout_list(base, tv)->duration;
  return tv->tv_sec == expect->tv_sec &&
      tv->tv_usec == expect->tv_usec;
}
#endif

/* Add the timeout for the first event in given common timeout list to the
 * event_base's minheap. */
static void
common_timeout_schedule(struct common_timeout_list *ctl,
    const struct timeval *now, struct event *head)
{
  struct timeval timeout = head->ev_timeout;
  timeout.tv_usec &= MICROSECONDS_MASK;
  event_add_nolock_(&ctl->timeout_event, &timeout, 1);
}

/* Callback: invoked when the timeout for a common timeout queue triggers.
 * This means that (at least) the first event in that queue should be run,
 * and the timeout should be rescheduled if there are more events. */
static void
common_timeout_callback(evutil_socket_t fd, short what, void *arg)
{
  struct timeval now;
  struct common_timeout_list *ctl = arg;
  struct event_base *base = ctl->base;
  struct event *ev = NULL;
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  gettime(base, &now);
  while (1) {
    int was_active;
    ev = TAILQ_FIRST(&ctl->events);
    if (!ev || ev->ev_timeout.tv_sec > now.tv_sec ||
        (ev->ev_timeout.tv_sec == now.tv_sec &&
      (ev->ev_timeout.tv_usec&MICROSECONDS_MASK) > now.tv_usec))
      break;
    was_active = ev->ev_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER);
    if (!was_active)
      event_del_nolock_(ev, EVENT_DEL_NOBLOCK);
    else
      event_queue_remove_timeout(base, ev);
    event_active_nolock_(ev, EV_TIMEOUT, 1);
  }
  if (ev)
    common_timeout_schedule(ctl, &now, ev);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
}

#define MAX_COMMON_TIMEOUTS 256

const struct timeval *
event_base_init_common_timeout(struct event_base *base,
    const struct timeval *duration)
{
  int i;
  struct timeval tv;
  const struct timeval *result=NULL;
  struct common_timeout_list *new_ctl;

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  if (duration->tv_usec > 1000000) {
    memcpy(&tv, duration, sizeof(struct timeval));
    if (is_common_timeout(duration, base))
      tv.tv_usec &= MICROSECONDS_MASK;
    tv.tv_sec += tv.tv_usec / 1000000;
    tv.tv_usec %= 1000000;
    duration = &tv;
  }
  for (i = 0; i < base->n_common_timeouts; ++i) {
    const struct common_timeout_list *ctl =
        base->common_timeout_queues[i];
    if (duration->tv_sec == ctl->duration.tv_sec &&
        duration->tv_usec ==
        (ctl->duration.tv_usec & MICROSECONDS_MASK)) {
      EVUTIL_ASSERT(is_common_timeout(&ctl->duration, base));
      result = &ctl->duration;
      goto done;
    }
  }
  if (base->n_common_timeouts == MAX_COMMON_TIMEOUTS) {
    event_warnx("%s: Too many common timeouts already in use; "
        "we only support %d per event_base", __func__,
        MAX_COMMON_TIMEOUTS);
    goto done;
  }
  if (base->n_common_timeouts_allocated == base->n_common_timeouts) {
    int n = base->n_common_timeouts < 16 ? 16 :
        base->n_common_timeouts*2;
    struct common_timeout_list **newqueues =
        mm_realloc(base->common_timeout_queues,
      n*sizeof(struct common_timeout_queue *));
    if (!newqueues) {
      event_warn("%s: realloc",__func__);
      goto done;
    }
    base->n_common_timeouts_allocated = n;
    base->common_timeout_queues = newqueues;
  }
  new_ctl = mm_calloc(1, sizeof(struct common_timeout_list));
  if (!new_ctl) {
    event_warn("%s: calloc",__func__);
    goto done;
  }
  TAILQ_INIT(&new_ctl->events);
  new_ctl->duration.tv_sec = duration->tv_sec;
  new_ctl->duration.tv_usec =
      duration->tv_usec | COMMON_TIMEOUT_MAGIC |
      (base->n_common_timeouts << COMMON_TIMEOUT_IDX_SHIFT);
  evtimer_assign(&new_ctl->timeout_event, base,
      common_timeout_callback, new_ctl);
  new_ctl->timeout_event.ev_flags |= EVLIST_INTERNAL;
  event_priority_set(&new_ctl->timeout_event, 0);
  new_ctl->base = base;
  base->common_timeout_queues[base->n_common_timeouts++] = new_ctl;
  result = &new_ctl->duration;

done:
  if (result)
    EVUTIL_ASSERT(is_common_timeout(result, base));

  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return result;
}

/* Closure function invoked when we're activating a persistent event. */
static inline void
event_persist_closure(struct event_base *base, struct event *ev)
{
  void (*evcb_callback)(evutil_socket_t, short, void *);

  // Other fields of *ev that must be stored before executing
  evutil_socket_t evcb_fd;
  short evcb_res;
  void *evcb_arg;

  /* reschedule the persistent event if we have a timeout. */
  if (ev->ev_io_timeout.tv_sec || ev->ev_io_timeout.tv_usec) {
    /* If there was a timeout, we want it to run at an interval of
     * ev_io_timeout after the last time it was _scheduled_ for,
     * not ev_io_timeout after _now_.  If it fired for another
     * reason, though, the timeout ought to start ticking _now_. */
    struct timeval run_at, relative_to, delay, now;
    ev_uint32_t usec_mask = 0;
    EVUTIL_ASSERT(is_same_common_timeout(&ev->ev_timeout,
      &ev->ev_io_timeout));
    gettime(base, &now);
    if (is_common_timeout(&ev->ev_timeout, base)) {
      delay = ev->ev_io_timeout;
      usec_mask = delay.tv_usec & ~MICROSECONDS_MASK;
      delay.tv_usec &= MICROSECONDS_MASK;
      if (ev->ev_res & EV_TIMEOUT) {
        relative_to = ev->ev_timeout;
        relative_to.tv_usec &= MICROSECONDS_MASK;
      } else {
        relative_to = now;
      }
    } else {
      delay = ev->ev_io_timeout;
      if (ev->ev_res & EV_TIMEOUT) {
        relative_to = ev->ev_timeout;
      } else {
        relative_to = now;
      }
    }
    evutil_timeradd(&relative_to, &delay, &run_at);
    if (evutil_timercmp(&run_at, &now, <)) {
      /* Looks like we missed at least one invocation due to
       * a clock jump, not running the event loop for a
       * while, really slow callbacks, or
       * something. Reschedule relative to now.
       */
      evutil_timeradd(&now, &delay, &run_at);
    }
    run_at.tv_usec |= usec_mask;
    event_add_nolock_(ev, &run_at, 1);
  }

  // Save our callback before we release the lock
  evcb_callback = ev->ev_callback;
  evcb_fd = ev->ev_fd;
  evcb_res = ev->ev_res;
  evcb_arg = ev->ev_arg;

  // Release the lock
  EVBASE_RELEASE_LOCK(base, th_base_lock);

  // Execute the callback
  (evcb_callback)(evcb_fd, evcb_res, evcb_arg);
}

/*
  Helper for event_process_active to process all the events in a single queue,
  releasing the lock as we go.  This function requires that the lock be held
  when it's invoked.  Returns -1 if we get a signal or an event_break that
  means we should stop processing any active events now.  Otherwise returns
  the number of non-internal event_callbacks that we processed.
*/
static int
event_process_active_single_queue(struct event_base *base,
    struct evcallback_list *activeq,
    int max_to_process, const struct timeval *endtime)
{
  struct event_callback *evcb;
  int count = 0;

  EVUTIL_ASSERT(activeq != NULL);

  for (evcb = TAILQ_FIRST(activeq); evcb; evcb = TAILQ_FIRST(activeq)) {
    struct event *ev = NULL;
    if (evcb->evcb_flags & EVLIST_INIT) {
      ev = event_callback_to_event(evcb);

      if (ev->ev_events & EV_PERSIST || ev->ev_flags & EVLIST_FINALIZING)
        event_queue_remove_active(base, evcb);
      else
        event_del_nolock_(ev, EVENT_DEL_NOBLOCK);
      event_debug((
          "event_process_active: event: %p, %s%s%scall %p",
          (void *)ev,
          ev->ev_res & EV_READ ? "EV_READ " : " ",
          ev->ev_res & EV_WRITE ? "EV_WRITE " : " ",
          ev->ev_res & EV_CLOSED ? "EV_CLOSED " : " ",
          (void *)ev->ev_callback));
    } else {
      event_queue_remove_active(base, evcb);
      event_debug(("event_process_active: event_callback %p, "
        "closure %d, call %p",
        (void *)evcb, evcb->evcb_closure, (void *)evcb->evcb_cb_union.evcb_callback));
    }
    // We don't want an infinite loop or use of memory after it is freed.
    // Hence, for next loop iteration, it is expected that `event_queue_remove_active` or `event_del_nolock_` have removed current event from the queue at this point.
    EVUTIL_ASSERT(evcb != TAILQ_FIRST(activeq));

    if (!(evcb->evcb_flags & EVLIST_INTERNAL))
      ++count;


    base->current_event = evcb;
#ifndef EVENT__DISABLE_THREAD_SUPPORT
    base->current_event_waiters = 0;
#endif

    switch (evcb->evcb_closure) {
    case EV_CLOSURE_EVENT_SIGNAL:
      EVUTIL_ASSERT(ev != NULL);
      event_signal_closure(base, ev);
      break;
    case EV_CLOSURE_EVENT_PERSIST:
      EVUTIL_ASSERT(ev != NULL);
      event_persist_closure(base, ev);
      break;
    case EV_CLOSURE_EVENT: {
      void (*evcb_callback)(evutil_socket_t, short, void *);
      short res;
      EVUTIL_ASSERT(ev != NULL);
      evcb_callback = *ev->ev_callback;
      res = ev->ev_res;
      EVBASE_RELEASE_LOCK(base, th_base_lock);
      evcb_callback(ev->ev_fd, res, ev->ev_arg);
    }
    break;
    case EV_CLOSURE_CB_SELF: {
      void (*evcb_selfcb)(struct event_callback *, void *) = evcb->evcb_cb_union.evcb_selfcb;
      EVBASE_RELEASE_LOCK(base, th_base_lock);
      evcb_selfcb(evcb, evcb->evcb_arg);
    }
    break;
    case EV_CLOSURE_EVENT_FINALIZE:
    case EV_CLOSURE_EVENT_FINALIZE_FREE: {
      void (*evcb_evfinalize)(struct event *, void *);
      int evcb_closure = evcb->evcb_closure;
      EVUTIL_ASSERT(ev != NULL);
      base->current_event = NULL;
      evcb_evfinalize = ev->ev_evcallback.evcb_cb_union.evcb_evfinalize;
      EVUTIL_ASSERT((evcb->evcb_flags & EVLIST_FINALIZING));
      EVBASE_RELEASE_LOCK(base, th_base_lock);
      event_debug_note_teardown_(ev);
      evcb_evfinalize(ev, ev->ev_arg);
      if (evcb_closure == EV_CLOSURE_EVENT_FINALIZE_FREE)
        mm_free(ev);
    }
    break;
    case EV_CLOSURE_CB_FINALIZE: {
      void (*evcb_cbfinalize)(struct event_callback *, void *) = evcb->evcb_cb_union.evcb_cbfinalize;
      base->current_event = NULL;
      EVUTIL_ASSERT((evcb->evcb_flags & EVLIST_FINALIZING));
      EVBASE_RELEASE_LOCK(base, th_base_lock);
      evcb_cbfinalize(evcb, evcb->evcb_arg);
    }
    break;
    default:
      EVUTIL_ASSERT(0);
    }

    EVBASE_ACQUIRE_LOCK(base, th_base_lock);
    base->current_event = NULL;
#ifndef EVENT__DISABLE_THREAD_SUPPORT
    if (base->current_event_waiters) {
      base->current_event_waiters = 0;
      EVTHREAD_COND_BROADCAST(base->current_event_cond);
    }
#endif

    if (base->event_break)
      return -1;
    if (count >= max_to_process)
      return count;
    if (count && endtime) {
      struct timeval now;
      update_time_cache(base);
      gettime(base, &now);
      if (evutil_timercmp(&now, endtime, >=))
        return count;
    }
    if (base->event_continue)
      break;
  }
  return count;
}

/*
 * Active events are stored in priority queues.  Lower priorities are always
 * process before higher priorities.  Low priority events can starve high
 * priority ones.
 */

static int
event_process_active(struct event_base *base)
{
  /* Caller must hold th_base_lock */
  struct evcallback_list *activeq = NULL;
  int i, c = 0;
  const struct timeval *endtime;
  struct timeval tv;
  const int maxcb = base->max_dispatch_callbacks;
  const int limit_after_prio = base->limit_callbacks_after_prio;
  if (base->max_dispatch_time.tv_sec >= 0) {
    update_time_cache(base);
    gettime(base, &tv);
    evutil_timeradd(&base->max_dispatch_time, &tv, &tv);
    endtime = &tv;
  } else {
    endtime = NULL;
  }

  for (i = 0; i < base->nactivequeues; ++i) {
    if (TAILQ_FIRST(&base->activequeues[i]) != NULL) {
      base->event_running_priority = i;
      activeq = &base->activequeues[i];
      if (i < limit_after_prio)
        c = event_process_active_single_queue(base, activeq,
            INT_MAX, NULL);
      else
        c = event_process_active_single_queue(base, activeq,
            maxcb, endtime);
      if (c < 0) {
        goto done;
      } else if (c > 0)
        break; /* Processed a real event; do not
          * consider lower-priority events */
      /* If we get here, all of the events we processed
       * were internal.  Continue. */
    }
  }

done:
  base->event_running_priority = -1;

  return c;
}

/*
 * Wait continuously for events.  We exit only if no events are left.
 */

int
event_dispatch(void)
{
  return (event_loop(0));
}

int
event_base_dispatch(struct event_base *event_base)
{
  return (event_base_loop(event_base, 0));
}

const char *
event_base_get_method(const struct event_base *base)
{
  EVUTIL_ASSERT(base);
  return (base->evsel->name);
}

const char *
event_base_get_signal_method(const struct event_base *base)
{
  EVUTIL_ASSERT(base);
  return (base->evsigsel->name);
}

/** Callback: used to implement event_base_loopexit by telling the event_base
 * that it's time to exit its loop. */
static void
event_loopexit_cb(evutil_socket_t fd, short what, void *arg)
{
  struct event_base *base = arg;
  base->event_gotterm = 1;
}

int
event_loopexit(const struct timeval *tv)
{
  return (event_once(-1, EV_TIMEOUT, event_loopexit_cb,
        current_base, tv));
}

int
event_base_loopexit(struct event_base *event_base, const struct timeval *tv)
{
  return (event_base_once(event_base, -1, EV_TIMEOUT, event_loopexit_cb,
        event_base, tv));
}

int
event_loopbreak(void)
{
  return (event_base_loopbreak(current_base));
}

int
event_base_loopbreak(struct event_base *event_base)
{
  int r = 0;
  if (event_base == NULL)
    return (-1);

  EVBASE_ACQUIRE_LOCK(event_base, th_base_lock);
  event_base->event_break = 1;

  if (EVBASE_NEED_NOTIFY(event_base)) {
    r = evthread_notify_base(event_base);
  } else {
    r = (0);
  }
  EVBASE_RELEASE_LOCK(event_base, th_base_lock);
  return r;
}

int
event_base_loopcontinue(struct event_base *event_base)
{
  int r = 0;
  if (event_base == NULL)
    return (-1);

  EVBASE_ACQUIRE_LOCK(event_base, th_base_lock);
  event_base->event_continue = 1;

  if (EVBASE_NEED_NOTIFY(event_base)) {
    r = evthread_notify_base(event_base);
  } else {
    r = (0);
  }
  EVBASE_RELEASE_LOCK(event_base, th_base_lock);
  return r;
}

int
event_base_got_break(struct event_base *event_base)
{
  int res;
  EVBASE_ACQUIRE_LOCK(event_base, th_base_lock);
  res = event_base->event_break;
  EVBASE_RELEASE_LOCK(event_base, th_base_lock);
  return res;
}

int
event_base_got_exit(struct event_base *event_base)
{
  int res;
  EVBASE_ACQUIRE_LOCK(event_base, th_base_lock);
  res = event_base->event_gotterm;
  EVBASE_RELEASE_LOCK(event_base, th_base_lock);
  return res;
}

/* not thread safe */

int
event_loop(int flags)
{
  return event_base_loop(current_base, flags);
}

int
event_base_loop(struct event_base *base, int flags)
{
  const struct eventop *evsel = base->evsel;
  struct timeval *tv_p;
  int res, done, retval = 0;
  struct evwatch_prepare_cb_info prepare_info;
  struct evwatch_check_cb_info check_info;
  struct evwatch *watcher;

  /* Grab the lock.  We will release it inside evsel.dispatch, and again
   * as we invoke watchers and user callbacks. */
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);

  if (base->running_loop) {
    event_warnx("%s: reentrant invocation.  Only one event_base_loop"
        " can run on each event_base at once.", __func__);
    EVBASE_RELEASE_LOCK(base, th_base_lock);
    return -1;
  }

  base->running_loop = 1;

  clear_time_cache(base);

  if (base->sig.ev_signal_added && base->sig.ev_n_signals_added)
    evsig_set_base_(base);

  done = 0;

#ifndef EVENT__DISABLE_THREAD_SUPPORT
  base->th_owner_id = EVTHREAD_GET_ID();
#endif

  base->event_gotterm = base->event_break = 0;

  while (!done) {
    struct timeval tv;

    base->event_continue = 0;
    base->n_deferreds_queued = 0;

    /* Terminate the loop if we have been asked to */
    if (base->event_gotterm) {
      break;
    }

    if (base->event_break) {
      break;
    }

    tv_p = &tv;
    if (!N_ACTIVE_CALLBACKS(base) && !(flags & EVLOOP_NONBLOCK)) {
      timeout_next(base, &tv_p);
    } else {
      /*
       * if we have active events, we just poll new events
       * without waiting.
       */
      evutil_timerclear(&tv);
    }

    /* If we have no events, we just exit */
    if (0==(flags&EVLOOP_NO_EXIT_ON_EMPTY) &&
        !event_haveevents(base) && !N_ACTIVE_CALLBACKS(base)) {
      event_debug(("%s: no events registered.", __func__));
      retval = 1;
      goto done;
    }

    event_queue_make_later_events_active(base);

    /* Invoke prepare watchers before polling for events */
    prepare_info.timeout = tv_p;
    TAILQ_FOREACH(watcher, &base->watchers[EVWATCH_PREPARE], next) {
      EVBASE_RELEASE_LOCK(base, th_base_lock);
      (*watcher->callback.prepare)(watcher, &prepare_info, watcher->arg);
      EVBASE_ACQUIRE_LOCK(base, th_base_lock);
    }

    clear_time_cache(base);

    res = evsel->dispatch(base, tv_p);

    if (res == -1) {
      event_debug(("%s: dispatch returned unsuccessfully.",
        __func__));
      retval = -1;
      goto done;
    }

    update_time_cache(base);

    /* Invoke check watchers after polling for events, and before
     * processing them */
    TAILQ_FOREACH(watcher, &base->watchers[EVWATCH_CHECK], next) {
      EVBASE_RELEASE_LOCK(base, th_base_lock);
      (*watcher->callback.check)(watcher, &check_info, watcher->arg);
      EVBASE_ACQUIRE_LOCK(base, th_base_lock);
    }

    timeout_process(base);

    if (N_ACTIVE_CALLBACKS(base)) {
      int n = event_process_active(base);
      if ((flags & EVLOOP_ONCE)
          && N_ACTIVE_CALLBACKS(base) == 0
          && n != 0)
        done = 1;
    } else if (flags & EVLOOP_NONBLOCK)
      done = 1;
  }
  event_debug(("%s: asked to terminate loop.", __func__));

done:
  clear_time_cache(base);
  base->running_loop = 0;

  EVBASE_RELEASE_LOCK(base, th_base_lock);

  return (retval);
}

/* One-time callback to implement event_base_once: invokes the user callback,
 * then deletes the allocated storage */
static void
event_once_cb(evutil_socket_t fd, short events, void *arg)
{
  struct event_once *eonce = arg;

  (*eonce->cb)(fd, events, eonce->arg);
  EVBASE_ACQUIRE_LOCK(eonce->ev.ev_base, th_base_lock);
  LIST_REMOVE(eonce, next_once);
  EVBASE_RELEASE_LOCK(eonce->ev.ev_base, th_base_lock);
  event_debug_unassign(&eonce->ev);
  mm_free(eonce);
}

/* not threadsafe, event scheduled once. */
int
event_once(evutil_socket_t fd, short events,
    void (*callback)(evutil_socket_t, short, void *),
    void *arg, const struct timeval *tv)
{
  return event_base_once(current_base, fd, events, callback, arg, tv);
}

/* Schedules an event once */
int
event_base_once(struct event_base *base, evutil_socket_t fd, short events,
    void (*callback)(evutil_socket_t, short, void *),
    void *arg, const struct timeval *tv)
{
  struct event_once *eonce;
  int res = 0;
  int activate = 0;

  if (!base)
    return (-1);

  /* We cannot support signals that just fire once, or persistent
   * events. */
  if (events & (EV_SIGNAL|EV_PERSIST))
    return (-1);

  if ((eonce = mm_calloc(1, sizeof(struct event_once))) == NULL)
    return (-1);

  eonce->cb = callback;
  eonce->arg = arg;

  if ((events & (EV_TIMEOUT|EV_SIGNAL|EV_READ|EV_WRITE|EV_CLOSED)) == EV_TIMEOUT) {
    evtimer_assign(&eonce->ev, base, event_once_cb, eonce);

    if (tv == NULL || ! evutil_timerisset(tv)) {
      /* If the event is going to become active immediately,
       * don't put it on the timeout queue.  This is one
       * idiom for scheduling a callback, so let's make
       * it fast (and order-preserving). */
      activate = 1;
    }
  } else if (events & (EV_READ|EV_WRITE|EV_CLOSED)) {
    events &= EV_READ|EV_WRITE|EV_CLOSED;

    event_assign(&eonce->ev, base, fd, events, event_once_cb, eonce);
  } else {
    /* Bad event combination */
    mm_free(eonce);
    return (-1);
  }


  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  if (activate)
    event_active_nolock_(&eonce->ev, EV_TIMEOUT, 1);
  else
    res = event_add_nolock_(&eonce->ev, tv, 0);

  if (res != 0) {
    mm_free(eonce);
    return (res);
  } else {
    LIST_INSERT_HEAD(&base->once_events, eonce, next_once);
  }
  EVBASE_RELEASE_LOCK(base, th_base_lock);

  return (0);
}

int
/* workaround for -Werror=maybe-uninitialized bug in gcc 11/12 */
#if defined(__GNUC__) && (__GNUC__ == 11 || __GNUC__ == 12)
__attribute__((noinline))
#endif
event_assign(struct event *ev, struct event_base *base, evutil_socket_t fd, short events, void (*callback)(evutil_socket_t, short, void *), void *arg)
{
  if (!base)
    base = current_base;
  if (arg == &event_self_cbarg_ptr_)
    arg = ev;

  if (!(events & EV_SIGNAL))
    event_debug_assert_socket_nonblocking_(fd);
  event_debug_assert_not_added_(ev);

  ev->ev_base = base;

  ev->ev_callback = callback;
  ev->ev_arg = arg;
  ev->ev_fd = fd;
  ev->ev_events = events;
  ev->ev_res = 0;
  ev->ev_flags = EVLIST_INIT;
  ev->ev_ncalls = 0;
  ev->ev_pncalls = NULL;

  if (events & EV_SIGNAL) {
    if ((events & (EV_READ|EV_WRITE|EV_CLOSED)) != 0) {
      event_warnx("%s: EV_SIGNAL is not compatible with "
          "EV_READ, EV_WRITE or EV_CLOSED", __func__);
      return -1;
    }
    ev->ev_closure = EV_CLOSURE_EVENT_SIGNAL;
  } else {
    if (events & EV_PERSIST) {
      evutil_timerclear(&ev->ev_io_timeout);
      ev->ev_closure = EV_CLOSURE_EVENT_PERSIST;
    } else {
      ev->ev_closure = EV_CLOSURE_EVENT;
    }
  }

  min_heap_elem_init_(ev);

  if (base != NULL) {
    /* by default, we put new events into the middle priority */
    ev->ev_pri = base->nactivequeues / 2;
  }

  event_debug_note_setup_(ev);

  return 0;
}

int
event_base_set(struct event_base *base, struct event *ev)
{
  /* Only innocent events may be assigned to a different base */
  if (ev->ev_flags != EVLIST_INIT)
    return (-1);

  event_debug_assert_is_setup_(ev);

  ev->ev_base = base;
  ev->ev_pri = base->nactivequeues/2;

  return (0);
}

void
event_set(struct event *ev, evutil_socket_t fd, short events,
    void (*callback)(evutil_socket_t, short, void *), void *arg)
{
  int r;
  r = event_assign(ev, current_base, fd, events, callback, arg);
  EVUTIL_ASSERT(r == 0);
}

void *
event_self_cbarg(void)
{
  return &event_self_cbarg_ptr_;
}

struct event *
event_base_get_running_event(struct event_base *base)
{
  struct event *ev = NULL;
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  if (EVBASE_IN_THREAD(base)) {
    struct event_callback *evcb = base->current_event;
    if (evcb->evcb_flags & EVLIST_INIT)
      ev = event_callback_to_event(evcb);
  }
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return ev;
}

struct event *
event_new(struct event_base *base, evutil_socket_t fd, short events, void (*cb)(evutil_socket_t, short, void *), void *arg)
{
  struct event *ev;
  ev = mm_malloc(sizeof(struct event));
  if (ev == NULL)
    return (NULL);
  if (event_assign(ev, base, fd, events, cb, arg) < 0) {
    mm_free(ev);
    return (NULL);
  }

  return (ev);
}

void
event_free(struct event *ev)
{
  /* This is disabled, so that events which have been finalized be a
   * valid target for event_free(). That's */
  // event_debug_assert_is_setup_(ev);

  /* make sure that this event won't be coming back to haunt us. */
  event_del(ev);
  event_debug_note_teardown_(ev);
  mm_free(ev);

}

void
event_debug_unassign(struct event *ev)
{
  event_debug_assert_not_added_(ev);
  event_debug_note_teardown_(ev);

  ev->ev_flags &= ~EVLIST_INIT;
}

#define EVENT_FINALIZE_FREE_ 0x10000
static int
event_finalize_nolock_(struct event_base *base, unsigned flags, struct event *ev, event_finalize_callback_fn cb)
{
  ev_uint8_t closure = (flags & EVENT_FINALIZE_FREE_) ?
      EV_CLOSURE_EVENT_FINALIZE_FREE : EV_CLOSURE_EVENT_FINALIZE;

  event_del_nolock_(ev, EVENT_DEL_NOBLOCK);
  ev->ev_closure = closure;
  ev->ev_evcallback.evcb_cb_union.evcb_evfinalize = cb;
  event_active_nolock_(ev, EV_FINALIZE, 1);
  ev->ev_flags |= EVLIST_FINALIZING;
  return 0;
}

static int
event_finalize_impl_(unsigned flags, struct event *ev, event_finalize_callback_fn cb)
{
  int r;
  struct event_base *base = ev->ev_base;
  if (EVUTIL_FAILURE_CHECK(!base)) {
    event_warnx("%s: event has no event_base set.", __func__);
    return -1;
  }

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  r = event_finalize_nolock_(base, flags, ev, cb);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return r;
}

int
event_finalize(unsigned flags, struct event *ev, event_finalize_callback_fn cb)
{
  return event_finalize_impl_(flags, ev, cb);
}

int
event_free_finalize(unsigned flags, struct event *ev, event_finalize_callback_fn cb)
{
  return event_finalize_impl_(flags|EVENT_FINALIZE_FREE_, ev, cb);
}

void
event_callback_finalize_nolock_(struct event_base *base, unsigned flags, struct event_callback *evcb, void (*cb)(struct event_callback *, void *))
{
  struct event *ev = NULL;
  if (evcb->evcb_flags & EVLIST_INIT) {
    ev = event_callback_to_event(evcb);
    event_del_nolock_(ev, EVENT_DEL_NOBLOCK);
  } else {
    event_callback_cancel_nolock_(base, evcb, 0); /*XXX can this fail?*/
  }

  evcb->evcb_closure = EV_CLOSURE_CB_FINALIZE;
  evcb->evcb_cb_union.evcb_cbfinalize = cb;
  event_callback_activate_nolock_(base, evcb); /* XXX can this really fail?*/
  evcb->evcb_flags |= EVLIST_FINALIZING;
}

void
event_callback_finalize_(struct event_base *base, unsigned flags, struct event_callback *evcb, void (*cb)(struct event_callback *, void *))
{
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  event_callback_finalize_nolock_(base, flags, evcb, cb);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
}

/** Internal: Finalize all of the n_cbs callbacks in evcbs.  The provided
 * callback will be invoked on *one of them*, after they have *all* been
 * finalized. */
int
event_callback_finalize_many_(struct event_base *base, int n_cbs, struct event_callback **evcbs, void (*cb)(struct event_callback *, void *))
{
  int n_pending = 0, i;

  if (base == NULL)
    base = current_base;

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);

  event_debug(("%s: %d events finalizing", __func__, n_cbs));

  /* At most one can be currently executing; the rest we just
   * cancel... But we always make sure that the finalize callback
   * runs. */
  for (i = 0; i < n_cbs; ++i) {
    struct event_callback *evcb = evcbs[i];
    if (evcb == base->current_event) {
      event_callback_finalize_nolock_(base, 0, evcb, cb);
      ++n_pending;
    } else {
      event_callback_cancel_nolock_(base, evcb, 0);
    }
  }

  if (n_pending == 0) {
    /* Just do the first one. */
    event_callback_finalize_nolock_(base, 0, evcbs[0], cb);
  }

  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return 0;
}

/*
 * Set's the priority of an event - if an event is already scheduled
 * changing the priority is going to fail.
 */

int
event_priority_set(struct event *ev, int pri)
{
  event_debug_assert_is_setup_(ev);

  if (ev->ev_flags & EVLIST_ACTIVE)
    return (-1);
  if (pri < 0 || pri >= ev->ev_base->nactivequeues)
    return (-1);

  ev->ev_pri = pri;

  return (0);
}

/*
 * Checks if a specific event is pending or scheduled.
 */

int
event_pending(const struct event *ev, short event, struct timeval *tv)
{
  int flags = 0;

  if (EVUTIL_FAILURE_CHECK(ev->ev_base == NULL)) {
    event_warnx("%s: event has no event_base set.", __func__);
    return 0;
  }

  EVBASE_ACQUIRE_LOCK(ev->ev_base, th_base_lock);
  event_debug_assert_is_setup_(ev);

  if (ev->ev_flags & EVLIST_INSERTED)
    flags |= (ev->ev_events & (EV_READ|EV_WRITE|EV_CLOSED|EV_SIGNAL));
  if (ev->ev_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER))
    flags |= ev->ev_res;
  if (ev->ev_flags & EVLIST_TIMEOUT)
    flags |= EV_TIMEOUT;

  event &= (EV_TIMEOUT|EV_READ|EV_WRITE|EV_CLOSED|EV_SIGNAL);

  /* See if there is a timeout that we should report */
  if (tv != NULL && (flags & event & EV_TIMEOUT)) {
    struct timeval tmp = ev->ev_timeout;
    tmp.tv_usec &= MICROSECONDS_MASK;
    /* correctly remamp to real time */
    evutil_timeradd(&ev->ev_base->tv_clock_diff, &tmp, tv);
  }

  EVBASE_RELEASE_LOCK(ev->ev_base, th_base_lock);

  return (flags & event);
}

int
event_initialized(const struct event *ev)
{
  if (!(ev->ev_flags & EVLIST_INIT))
    return 0;

  return 1;
}

void
event_get_assignment(const struct event *event, struct event_base **base_out, evutil_socket_t *fd_out, short *events_out, event_callback_fn *callback_out, void **arg_out)
{
  event_debug_assert_is_setup_(event);

  if (base_out)
    *base_out = event->ev_base;
  if (fd_out)
    *fd_out = event->ev_fd;
  if (events_out)
    *events_out = event->ev_events;
  if (callback_out)
    *callback_out = event->ev_callback;
  if (arg_out)
    *arg_out = event->ev_arg;
}

size_t
event_get_struct_event_size(void)
{
  return sizeof(struct event);
}

evutil_socket_t
event_get_fd(const struct event *ev)
{
  event_debug_assert_is_setup_(ev);
  return ev->ev_fd;
}

struct event_base *
event_get_base(const struct event *ev)
{
  event_debug_assert_is_setup_(ev);
  return ev->ev_base;
}

short
event_get_events(const struct event *ev)
{
  event_debug_assert_is_setup_(ev);
  return ev->ev_events;
}

event_callback_fn
event_get_callback(const struct event *ev)
{
  event_debug_assert_is_setup_(ev);
  return ev->ev_callback;
}

void *
event_get_callback_arg(const struct event *ev)
{
  event_debug_assert_is_setup_(ev);
  return ev->ev_arg;
}

int
event_get_priority(const struct event *ev)
{
  event_debug_assert_is_setup_(ev);
  return ev->ev_pri;
}

int
event_add(struct event *ev, const struct timeval *tv)
{
  int res;

  if (EVUTIL_FAILURE_CHECK(!ev->ev_base)) {
    event_warnx("%s: event has no event_base set.", __func__);
    return -1;
  }

  EVBASE_ACQUIRE_LOCK(ev->ev_base, th_base_lock);

  res = event_add_nolock_(ev, tv, 0);

  EVBASE_RELEASE_LOCK(ev->ev_base, th_base_lock);

  return (res);
}

/* Helper callback: wake an event_base from another thread.  This version
 * works by writing a byte to one end of a socketpair, so that the event_base
 * listening on the other end will wake up as the corresponding event
 * triggers */
static int
evthread_notify_base_default(struct event_base *base)
{
  char buf[1];
  ev_ssize_t r;
  buf[0] = (char) 0;
#ifdef _WIN32
  r = send(base->th_notify_fd[1], buf, 1, 0);
#else
  r = write(base->th_notify_fd[1], buf, 1);
#endif
  return (r < 0 && ! EVUTIL_ERR_IS_EAGAIN(errno)) ? -1 : 0;
}

#ifdef EVENT__HAVE_EVENTFD
/* Helper callback: wake an event_base from another thread.  This version
 * assumes that you have a working eventfd() implementation. */
static int
evthread_notify_base_eventfd(struct event_base *base)
{
  int efd = base->th_notify_fd[0];
  eventfd_t val;
  int ret;
  for (val=1;;val=1) {
    ret = eventfd_write(efd, val);
    if (ret < 0) {
      // When EAGAIN occurs, the eventfd counter hits the maximum value of the unsigned 64-bit.
      // We need to first drain the eventfd and then write again.
      //
      // Check out https://man7.org/linux/man-pages/man2/eventfd.2.html for details.
      if (errno == EAGAIN) {
        // It's ready to retry.
        if (eventfd_read(efd, &val) == 0 || errno == EAGAIN) {
          continue;
        }
      }
      // Unknown error occurs.
      ret = -1;
    }
    break;
  }

  return ret;
}
#endif


/** Tell the thread currently running the event_loop for base (if any) that it
 * needs to stop waiting in its dispatch function (if it is) and process all
 * active callbacks. */
static int
evthread_notify_base(struct event_base *base)
{
  EVENT_BASE_ASSERT_LOCKED(base);
  if (!base->th_notify_fn)
    return -1;
  if (base->is_notify_pending)
    return 0;
  base->is_notify_pending = 1;
  return base->th_notify_fn(base);
}

/* Implementation function to remove a timeout on a currently pending event.
 */
int
event_remove_timer_nolock_(struct event *ev)
{
  struct event_base *base = ev->ev_base;

  EVENT_BASE_ASSERT_LOCKED(base);
  event_debug_assert_is_setup_(ev);

  event_debug(("event_remove_timer_nolock: event: %p", (void *)ev));

  /* If it's not pending on a timeout, we don't need to do anything. */
  if (ev->ev_flags & EVLIST_TIMEOUT) {
    event_queue_remove_timeout(base, ev);
    evutil_timerclear(&ev->ev_io_timeout);
  }

  return (0);
}

int
event_remove_timer(struct event *ev)
{
  int res;

  if (EVUTIL_FAILURE_CHECK(!ev->ev_base)) {
    event_warnx("%s: event has no event_base set.", __func__);
    return -1;
  }

  EVBASE_ACQUIRE_LOCK(ev->ev_base, th_base_lock);

  res = event_remove_timer_nolock_(ev);

  EVBASE_RELEASE_LOCK(ev->ev_base, th_base_lock);

  return (res);
}

/* Implementation function to add an event.  Works just like event_add,
 * except: 1) it requires that we have the lock.  2) if tv_is_absolute is set,
 * we treat tv as an absolute time, not as an interval to add to the current
 * time */
int
event_add_nolock_(struct event *ev, const struct timeval *tv,
    int tv_is_absolute)
{
  struct event_base *base = ev->ev_base;
  int res = 0;
  int notify = 0;

  EVENT_BASE_ASSERT_LOCKED(base);
  event_debug_assert_is_setup_(ev);

  event_debug((
     "event_add: event: %p (fd "EV_SOCK_FMT"), %s%s%s%scall %p",
     (void *)ev,
     EV_SOCK_ARG(ev->ev_fd),
     ev->ev_events & EV_READ ? "EV_READ " : " ",
     ev->ev_events & EV_WRITE ? "EV_WRITE " : " ",
     ev->ev_events & EV_CLOSED ? "EV_CLOSED " : " ",
     tv ? "EV_TIMEOUT " : " ",
     (void *)ev->ev_callback));

  EVUTIL_ASSERT(!(ev->ev_flags & ~EVLIST_ALL));

  if (ev->ev_flags & EVLIST_FINALIZING) {
    /* XXXX debug */
    return (-1);
  }

  /*
   * prepare for timeout insertion further below, if we get a
   * failure on any step, we should not change any state.
   */
  if (tv != NULL && !(ev->ev_flags & EVLIST_TIMEOUT)) {
    if (min_heap_reserve_(&base->timeheap,
      1 + min_heap_size_(&base->timeheap)) == -1)
      return (-1);  /* ENOMEM == errno */
  }

  /* If the main thread is currently executing a signal event's
   * callback, and we are not the main thread, then we want to wait
   * until the callback is done before we mess with the event, or else
   * we can race on ev_ncalls and ev_pncalls below. */
#ifndef EVENT__DISABLE_THREAD_SUPPORT
  if (base->current_event == event_to_event_callback(ev) &&
      (ev->ev_events & EV_SIGNAL)
      && !EVBASE_IN_THREAD(base)) {
    ++base->current_event_waiters;
    EVTHREAD_COND_WAIT(base->current_event_cond, base->th_base_lock);
  }
#endif

  if ((ev->ev_events & (EV_READ|EV_WRITE|EV_CLOSED|EV_SIGNAL)) &&
      !(ev->ev_flags & (EVLIST_INSERTED|EVLIST_ACTIVE|EVLIST_ACTIVE_LATER))) {
    if (ev->ev_events & (EV_READ|EV_WRITE|EV_CLOSED))
      res = evmap_io_add_(base, ev->ev_fd, ev);
    else if (ev->ev_events & EV_SIGNAL)
      res = evmap_signal_add_(base, (int)ev->ev_fd, ev);
    if (res != -1)
      event_queue_insert_inserted(base, ev);
    if (res == 1) {
      /* evmap says we need to notify the main thread. */
      notify = 1;
      res = 0;
    }
  }

  /*
   * we should change the timeout state only if the previous event
   * addition succeeded.
   */
  if (res != -1 && tv != NULL) {
    struct timeval now;
    int common_timeout;
#ifdef USE_REINSERT_TIMEOUT
    int was_common;
    int old_timeout_idx;
#endif

    /*
     * for persistent timeout events, we remember the
     * timeout value and re-add the event.
     *
     * If tv_is_absolute, this was already set.
     */
    if (ev->ev_closure == EV_CLOSURE_EVENT_PERSIST && !tv_is_absolute)
      ev->ev_io_timeout = *tv;

#ifndef USE_REINSERT_TIMEOUT
    if (ev->ev_flags & EVLIST_TIMEOUT) {
      event_queue_remove_timeout(base, ev);
    }
#endif

    /* Check if it is active due to a timeout.  Rescheduling
     * this timeout before the callback can be executed
     * removes it from the active list. */
    if ((ev->ev_flags & EVLIST_ACTIVE) &&
        (ev->ev_res & EV_TIMEOUT)) {
      if (ev->ev_events & EV_SIGNAL) {
        /* See if we are just active executing
         * this event in a loop
         */
        if (ev->ev_ncalls && ev->ev_pncalls) {
          /* Abort loop */
          *ev->ev_pncalls = 0;
        }
      }

      event_queue_remove_active(base, event_to_event_callback(ev));
    }

    gettime(base, &now);

    common_timeout = is_common_timeout(tv, base);
#ifdef USE_REINSERT_TIMEOUT
    was_common = is_common_timeout(&ev->ev_timeout, base);
    old_timeout_idx = COMMON_TIMEOUT_IDX(&ev->ev_timeout);
#endif

    if (tv_is_absolute) {
      ev->ev_timeout = *tv;
    } else if (common_timeout) {
      struct timeval tmp = *tv;
      tmp.tv_usec &= MICROSECONDS_MASK;
      evutil_timeradd(&now, &tmp, &ev->ev_timeout);
      ev->ev_timeout.tv_usec |=
          (tv->tv_usec & ~MICROSECONDS_MASK);
    } else {
      evutil_timeradd(&now, tv, &ev->ev_timeout);
    }

    event_debug((
       "event_add: event %p, timeout in %d seconds %d useconds, call %p",
       (void *)ev, (int)tv->tv_sec, (int)tv->tv_usec, (void *)ev->ev_callback));

#ifdef USE_REINSERT_TIMEOUT
    event_queue_reinsert_timeout(base, ev, was_common, common_timeout, old_timeout_idx);
#else
    event_queue_insert_timeout(base, ev);
#endif

    if (common_timeout) {
      struct common_timeout_list *ctl =
          get_common_timeout_list(base, &ev->ev_timeout);
      if (ev == TAILQ_FIRST(&ctl->events)) {
        common_timeout_schedule(ctl, &now, ev);
      }
    } else {
      struct event* top = NULL;
      /* See if the earliest timeout is now earlier than it
       * was before: if so, we will need to tell the main
       * thread to wake up earlier than it would otherwise.
       * We double check the timeout of the top element to
       * handle time distortions due to system suspension.
       */
      if (min_heap_elt_is_top_(ev))
        notify = 1;
      else if ((top = min_heap_top_(&base->timeheap)) != NULL &&
           evutil_timercmp(&top->ev_timeout, &now, <))
        notify = 1;
    }
  }

  /* if we are not in the right thread, we need to wake up the loop */
  if (res != -1 && notify && EVBASE_NEED_NOTIFY(base))
    evthread_notify_base(base);

  event_debug_note_add_(ev);

  return (res);
}

static int
event_del_(struct event *ev, int blocking)
{
  int res;
  struct event_base *base = ev->ev_base;

  if (EVUTIL_FAILURE_CHECK(!base)) {
    event_warnx("%s: event has no event_base set.", __func__);
    return -1;
  }

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  res = event_del_nolock_(ev, blocking);
  EVBASE_RELEASE_LOCK(base, th_base_lock);

  return (res);
}

int
event_del(struct event *ev)
{
  return event_del_(ev, EVENT_DEL_AUTOBLOCK);
}

int
event_del_block(struct event *ev)
{
  return event_del_(ev, EVENT_DEL_BLOCK);
}

int
event_del_noblock(struct event *ev)
{
  return event_del_(ev, EVENT_DEL_NOBLOCK);
}

/** Helper for event_del: always called with th_base_lock held.
 *
 * "blocking" must be one of the EVENT_DEL_{BLOCK, NOBLOCK, AUTOBLOCK,
 * EVEN_IF_FINALIZING} values. See those for more information.
 */
int
event_del_nolock_(struct event *ev, int blocking)
{
  struct event_base *base;
  int res = 0, notify = 0;

  event_debug(("event_del: %p (fd "EV_SOCK_FMT"), callback %p",
    (void *)ev, EV_SOCK_ARG(ev->ev_fd), (void *)ev->ev_callback));

  /* An event without a base has not been added */
  if (ev->ev_base == NULL)
    return (-1);

  EVENT_BASE_ASSERT_LOCKED(ev->ev_base);

  if (blocking != EVENT_DEL_EVEN_IF_FINALIZING) {
    if (ev->ev_flags & EVLIST_FINALIZING) {
      /* XXXX Debug */
      return 0;
    }
  }

  base = ev->ev_base;

  EVUTIL_ASSERT(!(ev->ev_flags & ~EVLIST_ALL));

  /* See if we are just active executing this event in a loop */
  if (ev->ev_events & EV_SIGNAL) {
    if (ev->ev_ncalls && ev->ev_pncalls) {
      /* Abort loop */
      *ev->ev_pncalls = 0;
    }
  }

  if (ev->ev_flags & EVLIST_TIMEOUT) {
    /* Notify the base if this was the minimal timeout */
    if (min_heap_top_(&base->timeheap) == ev)
      notify = 1;
    event_queue_remove_timeout(base, ev);
  }

  if (ev->ev_flags & EVLIST_ACTIVE)
    event_queue_remove_active(base, event_to_event_callback(ev));
  else if (ev->ev_flags & EVLIST_ACTIVE_LATER)
    event_queue_remove_active_later(base, event_to_event_callback(ev));

  if (ev->ev_flags & EVLIST_INSERTED) {
    event_queue_remove_inserted(base, ev);
    if (ev->ev_events & (EV_READ|EV_WRITE|EV_CLOSED))
      res = evmap_io_del_(base, ev->ev_fd, ev);
    else
      res = evmap_signal_del_(base, (int)ev->ev_fd, ev);
    if (res == 1) {
      /* evmap says we need to notify the main thread. */
      notify = 1;
      res = 0;
    }
    /* If we do not have events, let's notify event base so it can
     * exit without waiting */
    if (!event_haveevents(base) && !N_ACTIVE_CALLBACKS(base))
      notify = 1;
  }

  /* if we are not in the right thread, we need to wake up the loop */
  if (res != -1 && notify && EVBASE_NEED_NOTIFY(base))
    evthread_notify_base(base);

  event_debug_note_del_(ev);

  /* If the main thread is currently executing this event's callback,
   * and we are not the main thread, then we want to wait until the
   * callback is done before returning. That way, when this function
   * returns, it will be safe to free the user-supplied argument.
   */
#ifndef EVENT__DISABLE_THREAD_SUPPORT
  if (blocking != EVENT_DEL_NOBLOCK &&
      base->current_event == event_to_event_callback(ev) &&
      !EVBASE_IN_THREAD(base) &&
      (blocking == EVENT_DEL_BLOCK || !(ev->ev_events & EV_FINALIZE))) {
    ++base->current_event_waiters;
    EVTHREAD_COND_WAIT(base->current_event_cond, base->th_base_lock);
  }
#endif

  return (res);
}

void
event_active(struct event *ev, int res, short ncalls)
{
  if (EVUTIL_FAILURE_CHECK(!ev->ev_base)) {
    event_warnx("%s: event has no event_base set.", __func__);
    return;
  }

  EVBASE_ACQUIRE_LOCK(ev->ev_base, th_base_lock);

  event_debug_assert_is_setup_(ev);

  event_active_nolock_(ev, res, ncalls);

  EVBASE_RELEASE_LOCK(ev->ev_base, th_base_lock);
}


void
event_active_nolock_(struct event *ev, int res, short ncalls)
{
  struct event_base *base;

  event_debug(("event_active: %p (fd "EV_SOCK_FMT"), res %d, callback %p",
    (void *)ev, EV_SOCK_ARG(ev->ev_fd), (int)res, (void *)ev->ev_callback));

  base = ev->ev_base;
  EVENT_BASE_ASSERT_LOCKED(base);

  if (ev->ev_flags & EVLIST_FINALIZING) {
    /* XXXX debug */
    return;
  }

  switch ((ev->ev_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER))) {
  default:
  case EVLIST_ACTIVE|EVLIST_ACTIVE_LATER:
    EVUTIL_ASSERT(0);
    break;
  case EVLIST_ACTIVE:
    /* We get different kinds of events, add them together */
    ev->ev_res |= res;
    return;
  case EVLIST_ACTIVE_LATER:
    ev->ev_res |= res;
    break;
  case 0:
    ev->ev_res = res;
    break;
  }

  if (ev->ev_pri < base->event_running_priority)
    base->event_continue = 1;

  if (ev->ev_events & EV_SIGNAL) {
#ifndef EVENT__DISABLE_THREAD_SUPPORT
    if (base->current_event == event_to_event_callback(ev) &&
        !EVBASE_IN_THREAD(base)) {
      ++base->current_event_waiters;
      EVTHREAD_COND_WAIT(base->current_event_cond, base->th_base_lock);
    }
#endif
    ev->ev_ncalls = ncalls;
    ev->ev_pncalls = NULL;
  }

  event_callback_activate_nolock_(base, event_to_event_callback(ev));
}

void
event_active_later_(struct event *ev, int res)
{
  EVBASE_ACQUIRE_LOCK(ev->ev_base, th_base_lock);
  event_active_later_nolock_(ev, res);
  EVBASE_RELEASE_LOCK(ev->ev_base, th_base_lock);
}

void
event_active_later_nolock_(struct event *ev, int res)
{
  struct event_base *base = ev->ev_base;
  EVENT_BASE_ASSERT_LOCKED(base);

  if (ev->ev_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER)) {
    /* We get different kinds of events, add them together */
    ev->ev_res |= res;
    return;
  }

  ev->ev_res = res;

  event_callback_activate_later_nolock_(base, event_to_event_callback(ev));
}

int
event_callback_activate_(struct event_base *base,
    struct event_callback *evcb)
{
  int r;
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  r = event_callback_activate_nolock_(base, evcb);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return r;
}

int
event_callback_activate_nolock_(struct event_base *base,
    struct event_callback *evcb)
{
  int r = 1;

  if (evcb->evcb_flags & EVLIST_FINALIZING)
    return 0;

  switch (evcb->evcb_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER)) {
  default:
    EVUTIL_ASSERT(0);
    EVUTIL_FALLTHROUGH;
  case EVLIST_ACTIVE_LATER:
    event_queue_remove_active_later(base, evcb);
    r = 0;
    break;
  case EVLIST_ACTIVE:
    return 0;
  case 0:
    break;
  }

  event_queue_insert_active(base, evcb);

  if (EVBASE_NEED_NOTIFY(base))
    evthread_notify_base(base);

  return r;
}

int
event_callback_activate_later_nolock_(struct event_base *base,
    struct event_callback *evcb)
{
  if (evcb->evcb_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER))
    return 0;

  event_queue_insert_active_later(base, evcb);
  if (EVBASE_NEED_NOTIFY(base))
    evthread_notify_base(base);
  return 1;
}

void
event_callback_init_(struct event_base *base,
    struct event_callback *cb)
{
  memset(cb, 0, sizeof(*cb));
  cb->evcb_pri = base->nactivequeues - 1;
}

int
event_callback_cancel_(struct event_base *base,
    struct event_callback *evcb)
{
  int r;
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  r = event_callback_cancel_nolock_(base, evcb, 0);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return r;
}

int
event_callback_cancel_nolock_(struct event_base *base,
    struct event_callback *evcb, int even_if_finalizing)
{
  if ((evcb->evcb_flags & EVLIST_FINALIZING) && !even_if_finalizing)
    return 0;

  if (evcb->evcb_flags & EVLIST_INIT)
    return event_del_nolock_(event_callback_to_event(evcb),
        even_if_finalizing ? EVENT_DEL_EVEN_IF_FINALIZING : EVENT_DEL_AUTOBLOCK);

  switch ((evcb->evcb_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER))) {
  default:
  case EVLIST_ACTIVE|EVLIST_ACTIVE_LATER:
    EVUTIL_ASSERT(0);
    break;
  case EVLIST_ACTIVE:
    /* We get different kinds of events, add them together */
    event_queue_remove_active(base, evcb);
    return 0;
  case EVLIST_ACTIVE_LATER:
    event_queue_remove_active_later(base, evcb);
    break;
  case 0:
    break;
  }

  return 0;
}

void
event_deferred_cb_init_(struct event_callback *cb, ev_uint8_t priority, deferred_cb_fn fn, void *arg)
{
  memset(cb, 0, sizeof(*cb));
  cb->evcb_cb_union.evcb_selfcb = fn;
  cb->evcb_arg = arg;
  cb->evcb_pri = priority;
  cb->evcb_closure = EV_CLOSURE_CB_SELF;
}

void
event_deferred_cb_set_priority_(struct event_callback *cb, ev_uint8_t priority)
{
  cb->evcb_pri = priority;
}

void
event_deferred_cb_cancel_(struct event_base *base, struct event_callback *cb)
{
  if (!base)
    base = current_base;
  event_callback_cancel_(base, cb);
}

#define MAX_DEFERREDS_QUEUED 32
int
event_deferred_cb_schedule_(struct event_base *base, struct event_callback *cb)
{
  int r = 1;
  if (!base)
    base = current_base;
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  if (base->n_deferreds_queued > MAX_DEFERREDS_QUEUED) {
    r = event_callback_activate_later_nolock_(base, cb);
  } else {
    r = event_callback_activate_nolock_(base, cb);
    if (r) {
      ++base->n_deferreds_queued;
    }
  }
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return r;
}

static int
timeout_next(struct event_base *base, struct timeval **tv_p)
{
  /* Caller must hold th_base_lock */
  struct timeval now;
  struct event *ev;
  struct timeval *tv = *tv_p;
  int res = 0;

  ev = min_heap_top_(&base->timeheap);

  if (ev == NULL) {
    /* if no time-based events are active wait for I/O */
    *tv_p = NULL;
    goto out;
  }

  if (gettime(base, &now) == -1) {
    res = -1;
    goto out;
  }

  if (evutil_timercmp(&ev->ev_timeout, &now, <=)) {
    evutil_timerclear(tv);
    goto out;
  }

  evutil_timersub(&ev->ev_timeout, &now, tv);

  EVUTIL_ASSERT(tv->tv_sec >= 0);
  EVUTIL_ASSERT(tv->tv_usec >= 0);
  event_debug(("timeout_next: event: %p, in %d seconds, %d useconds", (void *)ev, (int)tv->tv_sec, (int)tv->tv_usec));

out:
  return (res);
}

/* Activate every event whose timeout has elapsed. */
static void
timeout_process(struct event_base *base)
{
  /* Caller must hold lock. */
  struct timeval now;
  struct event *ev;

  if (min_heap_empty_(&base->timeheap)) {
    return;
  }

  gettime(base, &now);

  while ((ev = min_heap_top_(&base->timeheap))) {
    int was_active = ev->ev_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER);

    if (evutil_timercmp(&ev->ev_timeout, &now, >))
      break;

    if (!was_active)
      event_del_nolock_(ev, EVENT_DEL_NOBLOCK);
    else
      event_queue_remove_timeout(base, ev);

    event_debug(("timeout_process: event: %p, call %p (was active: %i)",
       (void *)ev, (void *)ev->ev_callback, was_active));
    event_active_nolock_(ev, EV_TIMEOUT, 1);
  }
}

#ifndef MAX
#define MAX(a,b) (((a)>(b))?(a):(b))
#endif

#define MAX_EVENT_COUNT(var, v) var = MAX(var, v)

/* These are a fancy way to spell
     if (~flags & EVLIST_INTERNAL)
         base->event_count--/++;
*/
#define DECR_EVENT_COUNT(base,flags) \
  ((base)->event_count -= !((flags) & EVLIST_INTERNAL))
#define INCR_EVENT_COUNT(base,flags) do {         \
  ((base)->event_count += !((flags) & EVLIST_INTERNAL));     \
  MAX_EVENT_COUNT((base)->event_count_max, (base)->event_count);   \
} while (0)

static void
event_queue_remove_inserted(struct event_base *base, struct event *ev)
{
  EVENT_BASE_ASSERT_LOCKED(base);
  if (EVUTIL_FAILURE_CHECK(!(ev->ev_flags & EVLIST_INSERTED))) {
    event_errx(1, "%s: %p(fd "EV_SOCK_FMT") not on queue %x", __func__,
                   (void *)ev, EV_SOCK_ARG(ev->ev_fd), EVLIST_INSERTED);
    return;
  }
  DECR_EVENT_COUNT(base, ev->ev_flags);
  ev->ev_flags &= ~EVLIST_INSERTED;
}
static void
event_queue_remove_active(struct event_base *base, struct event_callback *evcb)
{
  EVENT_BASE_ASSERT_LOCKED(base);
  if (EVUTIL_FAILURE_CHECK(!(evcb->evcb_flags & EVLIST_ACTIVE))) {
    event_errx(1, "%s: %p not on queue %x", __func__,
                          (void *)evcb, EVLIST_ACTIVE);
    return;
  }
  DECR_EVENT_COUNT(base, evcb->evcb_flags);
  evcb->evcb_flags &= ~EVLIST_ACTIVE;
  base->event_count_active--;

  TAILQ_REMOVE(&base->activequeues[evcb->evcb_pri],
      evcb, evcb_active_next);
}
static void
event_queue_remove_active_later(struct event_base *base, struct event_callback *evcb)
{
  EVENT_BASE_ASSERT_LOCKED(base);
  if (EVUTIL_FAILURE_CHECK(!(evcb->evcb_flags & EVLIST_ACTIVE_LATER))) {
    event_errx(1, "%s: %p not on queue %x", __func__,
                          (void *)evcb, EVLIST_ACTIVE_LATER);
    return;
  }
  DECR_EVENT_COUNT(base, evcb->evcb_flags);
  evcb->evcb_flags &= ~EVLIST_ACTIVE_LATER;
  base->event_count_active--;

  TAILQ_REMOVE(&base->active_later_queue, evcb, evcb_active_next);
}
static void
event_queue_remove_timeout(struct event_base *base, struct event *ev)
{
  EVENT_BASE_ASSERT_LOCKED(base);
  if (EVUTIL_FAILURE_CHECK(!(ev->ev_flags & EVLIST_TIMEOUT))) {
    event_errx(1, "%s: %p(fd "EV_SOCK_FMT") not on queue %x", __func__,
                   (void *)ev, EV_SOCK_ARG(ev->ev_fd), EVLIST_TIMEOUT);
    return;
  }
  DECR_EVENT_COUNT(base, ev->ev_flags);
  ev->ev_flags &= ~EVLIST_TIMEOUT;

  if (is_common_timeout(&ev->ev_timeout, base)) {
    struct common_timeout_list *ctl =
        get_common_timeout_list(base, &ev->ev_timeout);
    TAILQ_REMOVE(&ctl->events, ev,
        ev_timeout_pos.ev_next_with_common_timeout);
  } else {
    min_heap_erase_(&base->timeheap, ev);
  }
}

#ifdef USE_REINSERT_TIMEOUT
/* Remove and reinsert 'ev' into the timeout queue. */
static void
event_queue_reinsert_timeout(struct event_base *base, struct event *ev,
    int was_common, int is_common, int old_timeout_idx)
{
  struct common_timeout_list *ctl;
  if (!(ev->ev_flags & EVLIST_TIMEOUT)) {
    event_queue_insert_timeout(base, ev);
    return;
  }

  switch ((was_common<<1) | is_common) {
  case 3: /* Changing from one common timeout to another */
    ctl = base->common_timeout_queues[old_timeout_idx];
    TAILQ_REMOVE(&ctl->events, ev,
        ev_timeout_pos.ev_next_with_common_timeout);
    ctl = get_common_timeout_list(base, &ev->ev_timeout);
    insert_common_timeout_inorder(ctl, ev);
    break;
  case 2: /* Was common; is no longer common */
    ctl = base->common_timeout_queues[old_timeout_idx];
    TAILQ_REMOVE(&ctl->events, ev,
        ev_timeout_pos.ev_next_with_common_timeout);
    min_heap_push_(&base->timeheap, ev);
    break;
  case 1: /* Wasn't common; has become common. */
    min_heap_erase_(&base->timeheap, ev);
    ctl = get_common_timeout_list(base, &ev->ev_timeout);
    insert_common_timeout_inorder(ctl, ev);
    break;
  case 0: /* was in heap; is still on heap. */
    min_heap_adjust_(&base->timeheap, ev);
    break;
  default:
    EVUTIL_ASSERT(0); /* unreachable */
    break;
  }
}
#endif

/* Add 'ev' to the common timeout list in 'ev'. */
static void
insert_common_timeout_inorder(struct common_timeout_list *ctl,
    struct event *ev)
{
  struct event *e;
  /* By all logic, we should just be able to append 'ev' to the end of
   * ctl->events, since the timeout on each 'ev' is set to {the common
   * timeout} + {the time when we add the event}, and so the events
   * should arrive in order of their timeouts.  But just in case
   * there's some wacky threading issue going on, we do a search from
   * the end of 'ev' to find the right insertion point.
   */
  TAILQ_FOREACH_REVERSE(e, &ctl->events,
      event_list, ev_timeout_pos.ev_next_with_common_timeout) {
    /* This timercmp is a little sneaky, since both ev and e have
     * magic values in tv_usec.  Fortunately, they ought to have
     * the _same_ magic values in tv_usec.  Let's assert for that.
     */
    EVUTIL_ASSERT(
      is_same_common_timeout(&e->ev_timeout, &ev->ev_timeout));
    if (evutil_timercmp(&ev->ev_timeout, &e->ev_timeout, >=)) {
      TAILQ_INSERT_AFTER(&ctl->events, e, ev,
          ev_timeout_pos.ev_next_with_common_timeout);
      return;
    }
  }
  TAILQ_INSERT_HEAD(&ctl->events, ev,
      ev_timeout_pos.ev_next_with_common_timeout);
}

static void
event_queue_insert_inserted(struct event_base *base, struct event *ev)
{
  EVENT_BASE_ASSERT_LOCKED(base);

  if (EVUTIL_FAILURE_CHECK(ev->ev_flags & EVLIST_INSERTED)) {
    event_errx(1, "%s: %p(fd "EV_SOCK_FMT") already inserted", __func__,
                   (void *)ev, EV_SOCK_ARG(ev->ev_fd));
    return;
  }

  INCR_EVENT_COUNT(base, ev->ev_flags);

  ev->ev_flags |= EVLIST_INSERTED;
}

static void
event_queue_insert_active(struct event_base *base, struct event_callback *evcb)
{
  EVENT_BASE_ASSERT_LOCKED(base);

  if (evcb->evcb_flags & EVLIST_ACTIVE) {
    /* Double insertion is possible for active events */
    return;
  }

  INCR_EVENT_COUNT(base, evcb->evcb_flags);

  evcb->evcb_flags |= EVLIST_ACTIVE;

  base->event_count_active++;
  MAX_EVENT_COUNT(base->event_count_active_max, base->event_count_active);
  EVUTIL_ASSERT(evcb->evcb_pri < base->nactivequeues);
  TAILQ_INSERT_TAIL(&base->activequeues[evcb->evcb_pri],
      evcb, evcb_active_next);
}

static void
event_queue_insert_active_later(struct event_base *base, struct event_callback *evcb)
{
  EVENT_BASE_ASSERT_LOCKED(base);
  if (evcb->evcb_flags & (EVLIST_ACTIVE_LATER|EVLIST_ACTIVE)) {
    /* Double insertion is possible */
    return;
  }

  INCR_EVENT_COUNT(base, evcb->evcb_flags);
  evcb->evcb_flags |= EVLIST_ACTIVE_LATER;
  base->event_count_active++;
  MAX_EVENT_COUNT(base->event_count_active_max, base->event_count_active);
  EVUTIL_ASSERT(evcb->evcb_pri < base->nactivequeues);
  TAILQ_INSERT_TAIL(&base->active_later_queue, evcb, evcb_active_next);
}

static void
event_queue_insert_timeout(struct event_base *base, struct event *ev)
{
  EVENT_BASE_ASSERT_LOCKED(base);

  if (EVUTIL_FAILURE_CHECK(ev->ev_flags & EVLIST_TIMEOUT)) {
    event_errx(1, "%s: %p(fd "EV_SOCK_FMT") already on timeout", __func__,
                   (void *)ev, EV_SOCK_ARG(ev->ev_fd));
    return;
  }

  INCR_EVENT_COUNT(base, ev->ev_flags);

  ev->ev_flags |= EVLIST_TIMEOUT;

  if (is_common_timeout(&ev->ev_timeout, base)) {
    struct common_timeout_list *ctl =
        get_common_timeout_list(base, &ev->ev_timeout);
    insert_common_timeout_inorder(ctl, ev);
  } else {
    min_heap_push_(&base->timeheap, ev);
  }
}

static void
event_queue_make_later_events_active(struct event_base *base)
{
  struct event_callback *evcb;
  EVENT_BASE_ASSERT_LOCKED(base);

  while ((evcb = TAILQ_FIRST(&base->active_later_queue))) {
    TAILQ_REMOVE(&base->active_later_queue, evcb, evcb_active_next);
    evcb->evcb_flags = (evcb->evcb_flags & ~EVLIST_ACTIVE_LATER) | EVLIST_ACTIVE;
    EVUTIL_ASSERT(evcb->evcb_pri < base->nactivequeues);
    TAILQ_INSERT_TAIL(&base->activequeues[evcb->evcb_pri], evcb, evcb_active_next);
    base->n_deferreds_queued += (evcb->evcb_closure == EV_CLOSURE_CB_SELF);
  }
}

/* Functions for debugging */

const char *
event_get_version(void)
{
  return (EVENT__VERSION);
}

ev_uint32_t
event_get_version_number(void)
{
  return (EVENT__NUMERIC_VERSION);
}

/*
 * No thread-safe interface needed - the information should be the same
 * for all threads.
 */

const char *
event_get_method(void)
{
  return (current_base->evsel->name);
}

#ifndef EVENT__DISABLE_MM_REPLACEMENT
static void *(*mm_malloc_fn_)(size_t sz) = NULL;
static void *(*mm_realloc_fn_)(void *p, size_t sz) = NULL;
static void (*mm_free_fn_)(void *p) = NULL;

void *
event_mm_malloc_(size_t sz)
{
  if (sz == 0)
    return NULL;

  if (mm_malloc_fn_)
    return mm_malloc_fn_(sz);
  else
    return malloc(sz);
}

void *
event_mm_calloc_(size_t count, size_t size)
{
  if (count == 0 || size == 0)
    return NULL;

  if (mm_malloc_fn_) {
    size_t sz = count * size;
    void *p = NULL;
    if (count > EV_SIZE_MAX / size)
      goto error;
    p = mm_malloc_fn_(sz);
    if (p)
      return memset(p, 0, sz);
  } else {
    void *p = calloc(count, size);
#ifdef _WIN32
    /* Windows calloc doesn't reliably set ENOMEM */
    if (p == NULL)
      goto error;
#endif
    return p;
  }

error:
  errno = ENOMEM;
  return NULL;
}

char *
event_mm_strdup_(const char *str)
{
  if (!str) {
    errno = EINVAL;
    return NULL;
  }

  if (mm_malloc_fn_) {
    size_t ln = strlen(str);
    void *p = NULL;
    if (ln == EV_SIZE_MAX)
      goto error;
    p = mm_malloc_fn_(ln+1);
    if (p)
      return memcpy(p, str, ln+1);
  } else
#ifdef _WIN32
    return _strdup(str);
#else
    return strdup(str);
#endif

error:
  errno = ENOMEM;
  return NULL;
}

void *
event_mm_realloc_(void *ptr, size_t sz)
{
  if (mm_realloc_fn_)
    return mm_realloc_fn_(ptr, sz);
  else
    return realloc(ptr, sz);
}

void
event_mm_free_(void *ptr)
{
  if (mm_free_fn_)
    mm_free_fn_(ptr);
  else
    free(ptr);
}

void
event_set_mem_functions(void *(*malloc_fn)(size_t sz),
      void *(*realloc_fn)(void *ptr, size_t sz),
      void (*free_fn)(void *ptr))
{
  mm_malloc_fn_ = malloc_fn;
  mm_realloc_fn_ = realloc_fn;
  mm_free_fn_ = free_fn;
}
#endif

#ifdef EVENT__HAVE_EVENTFD
static void
evthread_notify_drain_eventfd(evutil_socket_t fd, short what, void *arg)
{
  struct event_base *base = arg;
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  base->is_notify_pending = 0;
  EVBASE_RELEASE_LOCK(base, th_base_lock);
}
#endif

static void
evthread_notify_drain_default(evutil_socket_t fd, short what, void *arg)
{
  unsigned char buf[1024];
  struct event_base *base = arg;
#ifdef _WIN32
  while (recv(fd, (char*)buf, sizeof(buf), 0) > 0)
    ;
#else
  while (read(fd, (char*)buf, sizeof(buf)) > 0)
    ;
#endif

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  base->is_notify_pending = 0;
  EVBASE_RELEASE_LOCK(base, th_base_lock);
}

int
evthread_make_base_notifiable(struct event_base *base)
{
  int r;
  if (!base)
    return -1;

  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  r = evthread_make_base_notifiable_nolock_(base);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return r;
}

static int
evthread_make_base_notifiable_nolock_(struct event_base *base)
{
  void (*cb)(evutil_socket_t, short, void *);
  int (*notify)(struct event_base *);

  if (base->th_notify_fn != NULL) {
    /* The base is already notifiable: we're doing fine. */
    return 0;
  }

#if defined(EVENT__HAVE_WORKING_KQUEUE)
  if (base->evsel == &kqops && event_kq_add_notify_event_(base) == 0) {
    base->th_notify_fn = event_kq_notify_base_;
    /* No need to add an event here; the backend can wake
     * itself up just fine. */
    return 0;
  }
#endif

#ifdef EVENT__HAVE_EVENTFD
  base->th_notify_fd[0] = evutil_eventfd_(0,
      EVUTIL_EFD_CLOEXEC|EVUTIL_EFD_NONBLOCK);
  if (base->th_notify_fd[0] >= 0) {
    base->th_notify_fd[1] = -1;
    notify = evthread_notify_base_eventfd;
    cb = evthread_notify_drain_eventfd;
  } else
#endif
  if (evutil_make_internal_pipe_(base->th_notify_fd) == 0) {
    notify = evthread_notify_base_default;
    cb = evthread_notify_drain_default;
  } else {
    return -1;
  }

  base->th_notify_fn = notify;

  /* prepare an event that we can use for wakeup */
  event_assign(&base->th_notify, base, base->th_notify_fd[0],
         EV_READ|EV_PERSIST|EV_ET, cb, base);

  /* we need to mark this as internal event */
  base->th_notify.ev_flags |= EVLIST_INTERNAL;
  event_priority_set(&base->th_notify, 0);

  return event_add_nolock_(&base->th_notify, NULL, 0);
}

int
event_base_foreach_event_nolock_(struct event_base *base,
    event_base_foreach_event_cb fn, void *arg)
{
  int r, i;
  size_t u;
  struct event *ev;

  /* Start out with all the EVLIST_INSERTED events. */
  if ((r = evmap_foreach_event_(base, fn, arg)))
    return r;

  /* Okay, now we deal with those events that have timeouts and are in
   * the min-heap. */
  for (u = 0; u < base->timeheap.n; ++u) {
    ev = base->timeheap.p[u];
    if (ev->ev_flags & EVLIST_INSERTED) {
      /* we already processed this one */
      continue;
    }
    if ((r = fn(base, ev, arg)))
      return r;
  }

  /* Now for the events in one of the timeout queues.
   * the min-heap. */
  for (i = 0; i < base->n_common_timeouts; ++i) {
    struct common_timeout_list *ctl =
        base->common_timeout_queues[i];
    TAILQ_FOREACH(ev, &ctl->events,
        ev_timeout_pos.ev_next_with_common_timeout) {
      if (ev->ev_flags & EVLIST_INSERTED) {
        /* we already processed this one */
        continue;
      }
      if ((r = fn(base, ev, arg)))
        return r;
    }
  }

  /* Finally, we deal wit all the active events that we haven't touched
   * yet. */
  for (i = 0; i < base->nactivequeues; ++i) {
    struct event_callback *evcb;
    TAILQ_FOREACH(evcb, &base->activequeues[i], evcb_active_next) {
      if ((evcb->evcb_flags & (EVLIST_INIT|EVLIST_INSERTED|EVLIST_TIMEOUT)) != EVLIST_INIT) {
        /* This isn't an event (evlist_init clear), or
         * we already processed it. (inserted or
         * timeout set */
        continue;
      }
      ev = event_callback_to_event(evcb);
      if ((r = fn(base, ev, arg)))
        return r;
    }
  }

  return 0;
}

/* Helper for event_base_dump_events: called on each event in the event base;
 * dumps only the inserted events. */
static int
dump_inserted_event_fn(const struct event_base *base, const struct event *e, void *arg)
{
  FILE *output = arg;
  const char *gloss = (e->ev_events & EV_SIGNAL) ?
      "sig" : "fd ";

  if (! (e->ev_flags & (EVLIST_INSERTED|EVLIST_TIMEOUT)))
    return 0;

  fprintf(output, "  %p [%s "EV_SOCK_FMT"]%s%s%s%s%s%s%s",
      (void*)e, gloss, EV_SOCK_ARG(e->ev_fd),
      (e->ev_events&EV_READ)?" Read":"",
      (e->ev_events&EV_WRITE)?" Write":"",
      (e->ev_events&EV_CLOSED)?" EOF":"",
      (e->ev_events&EV_SIGNAL)?" Signal":"",
      (e->ev_events&EV_PERSIST)?" Persist":"",
      (e->ev_events&EV_ET)?" ET":"",
      (e->ev_flags&EVLIST_INTERNAL)?" Internal":"");
  if (e->ev_flags & EVLIST_TIMEOUT) {
    struct timeval tv;
    tv.tv_sec = e->ev_timeout.tv_sec;
    tv.tv_usec = e->ev_timeout.tv_usec & MICROSECONDS_MASK;
    evutil_timeradd(&tv, &base->tv_clock_diff, &tv);
    fprintf(output, " Timeout=%ld.%06d",
        (long)tv.tv_sec, (int)(tv.tv_usec & MICROSECONDS_MASK));
  }
  fputc('\n', output);

  return 0;
}

/* Helper for event_base_dump_events: called on each event in the event base;
 * dumps only the active events. */
static int
dump_active_event_fn(const struct event_base *base, const struct event *e, void *arg)
{
  FILE *output = arg;
  const char *gloss = (e->ev_events & EV_SIGNAL) ?
      "sig" : "fd ";

  if (! (e->ev_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER)))
    return 0;

  fprintf(output, "  %p [%s "EV_SOCK_FMT", priority=%d]%s%s%s%s%s active%s%s\n",
      (void*)e, gloss, EV_SOCK_ARG(e->ev_fd), e->ev_pri,
      (e->ev_res&EV_READ)?" Read":"",
      (e->ev_res&EV_WRITE)?" Write":"",
      (e->ev_res&EV_CLOSED)?" EOF":"",
      (e->ev_res&EV_SIGNAL)?" Signal":"",
      (e->ev_res&EV_TIMEOUT)?" Timeout":"",
      (e->ev_flags&EVLIST_INTERNAL)?" [Internal]":"",
      (e->ev_flags&EVLIST_ACTIVE_LATER)?" [NextTime]":"");

  return 0;
}

int
event_base_foreach_event(struct event_base *base,
    event_base_foreach_event_cb fn, void *arg)
{
  int r;
  if ((!fn) || (!base)) {
    return -1;
  }
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  r = event_base_foreach_event_nolock_(base, fn, arg);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
  return r;
}


void
event_base_dump_events(struct event_base *base, FILE *output)
{
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  fprintf(output, "Inserted events:\n");
  event_base_foreach_event_nolock_(base, dump_inserted_event_fn, output);

  fprintf(output, "Active events:\n");
  event_base_foreach_event_nolock_(base, dump_active_event_fn, output);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
}

void
event_base_active_by_fd(struct event_base *base, evutil_socket_t fd, short events)
{
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);

  /* Activate any non timer events */
  if (!(events & EV_TIMEOUT)) {
    evmap_io_active_(base, fd, events & (EV_READ|EV_WRITE|EV_CLOSED));
  } else {
    /* If we want to activate timer events, loop and activate each event with
     * the same fd in both the timeheap and common timeouts list */
    int i;
    size_t u;
    struct event *ev;

    for (u = 0; u < base->timeheap.n; ++u) {
      ev = base->timeheap.p[u];
      if (ev->ev_fd == fd) {
        event_active_nolock_(ev, EV_TIMEOUT, 1);
      }
    }

    for (i = 0; i < base->n_common_timeouts; ++i) {
      struct common_timeout_list *ctl = base->common_timeout_queues[i];
      TAILQ_FOREACH(ev, &ctl->events,
        ev_timeout_pos.ev_next_with_common_timeout) {
        if (ev->ev_fd == fd) {
          event_active_nolock_(ev, EV_TIMEOUT, 1);
        }
      }
    }
  }

  EVBASE_RELEASE_LOCK(base, th_base_lock);
}

void
event_base_active_by_signal(struct event_base *base, int sig)
{
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  evmap_signal_active_(base, sig, 1);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
}


void
event_base_add_virtual_(struct event_base *base)
{
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  base->virtual_event_count++;
  MAX_EVENT_COUNT(base->virtual_event_count_max, base->virtual_event_count);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
}

void
event_base_del_virtual_(struct event_base *base)
{
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  EVUTIL_ASSERT(base->virtual_event_count > 0);
  base->virtual_event_count--;
  if (base->virtual_event_count == 0 && EVBASE_NEED_NOTIFY(base))
    evthread_notify_base(base);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
}

static void
event_free_debug_globals_locks(void)
{
#ifndef EVENT__DISABLE_THREAD_SUPPORT
#ifndef EVENT__DISABLE_DEBUG_MODE
  if (event_debug_map_lock_ != NULL) {
    EVTHREAD_FREE_LOCK(event_debug_map_lock_, 0);
    event_debug_map_lock_ = NULL;
    evthreadimpl_disable_lock_debugging_();
  }
#endif /* EVENT__DISABLE_DEBUG_MODE */
#endif /* EVENT__DISABLE_THREAD_SUPPORT */
  return;
}

static void
event_free_debug_globals(void)
{
  event_free_debug_globals_locks();
}

static void
event_free_evsig_globals(void)
{
  evsig_free_globals_();
}

static void
event_free_evutil_globals(void)
{
  evutil_free_globals_();
}

static void
event_free_globals(void)
{
  event_free_debug_globals();
  event_free_evsig_globals();
  event_free_evutil_globals();
}

void
libevent_global_shutdown(void)
{
  event_disable_debug_mode();
  event_free_globals();
}

#ifndef EVENT__DISABLE_THREAD_SUPPORT
int
event_global_setup_locks_(const int enable_locks)
{
#ifndef EVENT__DISABLE_DEBUG_MODE
  EVTHREAD_SETUP_GLOBAL_LOCK(event_debug_map_lock_, 0);
#endif
  if (evsig_global_setup_locks_(enable_locks) < 0)
    return -1;
  if (evutil_global_setup_locks_(enable_locks) < 0)
    return -1;
  if (evutil_secure_rng_global_setup_locks_(enable_locks) < 0)
    return -1;
  return 0;
}
#endif

void
event_base_assert_ok_(struct event_base *base)
{
  EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  event_base_assert_ok_nolock_(base);
  EVBASE_RELEASE_LOCK(base, th_base_lock);
}

void
event_base_assert_ok_nolock_(struct event_base *base)
{
  int i;
  size_t u;
  int count;

  /* First do checks on the per-fd and per-signal lists */
  evmap_check_integrity_(base);

  /* Check the heap property */
  for (u = 1; u < base->timeheap.n; ++u) {
    size_t parent = (u - 1) / 2;
    struct event *ev, *p_ev;
    ev = base->timeheap.p[u];
    p_ev = base->timeheap.p[parent];
    EVUTIL_ASSERT(ev->ev_flags & EVLIST_TIMEOUT);
    EVUTIL_ASSERT(evutil_timercmp(&p_ev->ev_timeout, &ev->ev_timeout, <=));
    EVUTIL_ASSERT(ev->ev_timeout_pos.min_heap_idx == u);
  }

  /* Check that the common timeouts are fine */
  for (i = 0; i < base->n_common_timeouts; ++i) {
    struct common_timeout_list *ctl = base->common_timeout_queues[i];
    struct event *last=NULL, *ev;

    EVUTIL_ASSERT_TAILQ_OK(&ctl->events, event, ev_timeout_pos.ev_next_with_common_timeout);

    TAILQ_FOREACH(ev, &ctl->events, ev_timeout_pos.ev_next_with_common_timeout) {
      if (last)
        EVUTIL_ASSERT(evutil_timercmp(&last->ev_timeout, &ev->ev_timeout, <=));
      EVUTIL_ASSERT(ev->ev_flags & EVLIST_TIMEOUT);
      EVUTIL_ASSERT(is_common_timeout(&ev->ev_timeout,base));
      EVUTIL_ASSERT(COMMON_TIMEOUT_IDX(&ev->ev_timeout) == i);
      last = ev;
    }
  }

  /* Check the active queues. */
  count = 0;
  for (i = 0; i < base->nactivequeues; ++i) {
    struct event_callback *evcb;
    EVUTIL_ASSERT_TAILQ_OK(&base->activequeues[i], event_callback, evcb_active_next);
    TAILQ_FOREACH(evcb, &base->activequeues[i], evcb_active_next) {
      EVUTIL_ASSERT((evcb->evcb_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER)) == EVLIST_ACTIVE);
      EVUTIL_ASSERT(evcb->evcb_pri == i);
      ++count;
    }
  }

  {
    struct event_callback *evcb;
    TAILQ_FOREACH(evcb, &base->active_later_queue, evcb_active_next) {
      EVUTIL_ASSERT((evcb->evcb_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER)) == EVLIST_ACTIVE_LATER);
      ++count;
    }
  }
  EVUTIL_ASSERT(count == base->event_count_active);
}

Coverage Report

Created: 2025-07-11 06:57