/*      $NetBSD: event.c,v 1.7 2024/08/18 20:47:21 christos Exp $       */

/*
* Copyright (c) 2000-2007 Niels Provos <[email protected]>
* 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 "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 _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
       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__, 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__, 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__, 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__, 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 5

/** 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

       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, n_deleted=0;
       struct event *ev;
       /* 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: %d 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);

       /* 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)
{
       short ncalls;
       int should_break;

       /* Allows deletes to work */
       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;
               }
       }
}

/* 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) {
               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;
               event_del_nolock_(ev, EVENT_DEL_NOBLOCK);
               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",
                           ev,
                           ev->ev_res & EV_READ ? "EV_READ " : " ",
                           ev->ev_res & EV_WRITE ? "EV_WRITE " : " ",
                           ev->ev_res & EV_CLOSED ? "EV_CLOSED " : " ",
                           ev->ev_callback));
               } else {
                       event_queue_remove_active(base, evcb);
                       event_debug(("event_process_active: event_callback %p, "
                               "closure %d, call %p",
                               evcb, evcb->evcb_closure, evcb->evcb_cb_union.evcb_callback));
               }

               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);
}

/** 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;
       struct timeval *tv_p;
       int res, done, retval = 0;

       /* Grab the lock.  We will release it inside evsel.dispatch, and again
        * as we invoke 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) {
               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);

               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);

               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);
       }

       if (res == 0) {
               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
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];
       int 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)
{
       ev_uint64_t msg = 1;
       int r;
       do {
               r = write(base->th_notify_fd[0], (void*) &msg, sizeof(msg));
       } while (r < 0 && errno == EAGAIN);

       return (r < 0) ? -1 : 0;
}
#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", 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_.ev_io.ev_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",
                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 " : " ",
                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",
                        ev, (int)tv->tv_sec, (int)tv->tv_usec, 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",
               ev, EV_SOCK_ARG(ev->ev_fd), 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) {
               /* NOTE: We never need to notify the main thread because of a
                * deleted timeout event: all that could happen if we don't is
                * that the dispatch loop might wake up too early.  But the
                * point of notifying the main thread _is_ to wake up the
                * dispatch loop early anyway, so we wouldn't gain anything by
                * doing it.
                */
               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",
               ev, EV_SOCK_ARG(ev->ev_fd), (int)res, 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", 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))) {
               if (evutil_timercmp(&ev->ev_timeout, &now, >))
                       break;

               /* delete this event from the I/O queues */
               event_del_nolock_(ev, EVENT_DEL_NOBLOCK);

               event_debug(("timeout_process: event: %p, call %p",
                        ev, ev->ev_callback));
               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__,
                   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__,
                          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__,
                          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__,
                   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 timeeouts.  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__,
                   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__,
                   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)
{
       ev_uint64_t msg;
       ev_ssize_t r;
       struct event_base *base = arg;

       r = read(fd, (void*) &msg, sizeof(msg));
       if (r<0 && errno != EAGAIN) {
               event_sock_warn(fd, "Error reading from eventfd");
       }
       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, 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;
       unsigned 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;
               unsigned 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;
       int count;

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

       /* Check the heap property */
       for (i = 1; i < (int)base->timeheap.n; ++i) {
               int parent = (i - 1) / 2;
               struct event *ev, *p_ev;
               ev = base->timeheap.p[i];
               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 == i);
       }

       /* 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);
}