text: /*
   * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
   * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  #include "event2/event-config.h"
  #include "evconfig-private.h"
  
  #ifdef _WIN32
  #include <winsock2.h>
  #define WIN32_LEAN_AND_MEAN
  #include <windows.h>
  #undef WIN32_LEAN_AND_MEAN
  #endif
  #include <sys/types.h>
  #if !defined(_WIN32) && defined(EVENT__HAVE_SYS_TIME_H)
  #include <sys/time.h>
  #endif
  #include <sys/queue.h>
  #ifdef EVENT__HAVE_SYS_SOCKET_H
  #include <sys/socket.h>
  #endif
  #include <stdio.h>
  #include <stdlib.h>
  #ifdef EVENT__HAVE_UNISTD_H
  #include <unistd.h>
  #endif
  #include <ctype.h>
  #include <errno.h>
  #include <signal.h>
  #include <string.h>
  #include <time.h>
  #include <limits.h>
  #ifdef EVENT__HAVE_FCNTL_H
  #include <fcntl.h>
  #endif
  
  #include "event2/event.h"
  #include "event2/event_struct.h"
  #include "event2/event_compat.h"
  #include "event2/watch.h"
  #include "event-internal.h"
  #include "defer-internal.h"
  #include "evthread-internal.h"
  #include "event2/thread.h"
  #include "event2/util.h"
  #include "log-internal.h"
  #include "evmap-internal.h"
  #include "iocp-internal.h"
  #include "changelist-internal.h"
  #define HT_NO_CACHE_HASH_VALUES
  #include "ht-internal.h"
  #include "util-internal.h"
  
  
  #ifdef EVENT__HAVE_WORKING_KQUEUE
  #include "kqueue-internal.h"
  #endif
  
  #ifdef EVENT__HAVE_EVENT_PORTS
  extern const struct eventop evportops;
  #endif
  #ifdef EVENT__HAVE_SELECT
  extern const struct eventop selectops;
  #endif
  #ifdef EVENT__HAVE_POLL
  extern const struct eventop pollops;
  #endif
  #ifdef EVENT__HAVE_EPOLL
  extern const struct eventop epollops;
  #endif
  #ifdef EVENT__HAVE_WORKING_KQUEUE
  extern const struct eventop kqops;
  #endif
  #ifdef EVENT__HAVE_DEVPOLL
  extern const struct eventop devpollops;
  #endif
  #ifdef EVENT__HAVE_WEPOLL
  extern const struct eventop wepollops;
  #endif
  #ifdef _WIN32
  extern const struct eventop win32ops;
  #endif
  
  /* Array of backends in order of preference. */
  static const struct eventop *eventops[] = {
  #ifdef EVENT__HAVE_EVENT_PORTS
  	&evportops,
  #endif
  #ifdef EVENT__HAVE_WORKING_KQUEUE
  	&kqops,
  #endif
  #ifdef EVENT__HAVE_EPOLL
  	&epollops,
  #endif
  #ifdef EVENT__HAVE_DEVPOLL
  	&devpollops,
  #endif
  #ifdef EVENT__HAVE_POLL
  	&pollops,
  #endif
  #ifdef EVENT__HAVE_SELECT
  	&selectops,
  #endif
  #ifdef _WIN32
  	&win32ops,
  #endif
  #ifdef EVENT__HAVE_WEPOLL
  	&wepollops,
  #endif
  	NULL
  };
  
  /* Global state; deprecated */
  EVENT2_EXPORT_SYMBOL
  struct event_base *event_global_current_base_ = NULL;
  #define current_base event_global_current_base_
  
  /* Global state */
  
  static void *event_self_cbarg_ptr_ = NULL;
  
  /* Prototypes */
  static void	event_queue_insert_active(struct event_base *, struct event_callback *);
  static void	event_queue_insert_active_later(struct event_base *, struct event_callback *);
  static void	event_queue_insert_timeout(struct event_base *, struct event *);
  static void	event_queue_insert_inserted(struct event_base *, struct event *);
  static void	event_queue_remove_active(struct event_base *, struct event_callback *);
  static void	event_queue_remove_active_later(struct event_base *, struct event_callback *);
  static void	event_queue_remove_timeout(struct event_base *, struct event *);
  static void	event_queue_remove_inserted(struct event_base *, struct event *);
  static void event_queue_make_later_events_active(struct event_base *base);
  
  static int evthread_make_base_notifiable_nolock_(struct event_base *base);
  static int event_del_(struct event *ev, int blocking);
  
  #ifdef USE_REINSERT_TIMEOUT
  /* This code seems buggy; only turn it on if we find out what the trouble is. */
  static void	event_queue_reinsert_timeout(struct event_base *,struct event *, int was_common, int is_common, int old_timeout_idx);
  #endif
  
  static int	event_haveevents(struct event_base *);
  
  static int	event_process_active(struct event_base *);
  
  static int	timeout_next(struct event_base *, struct timeval **);
  static void	timeout_process(struct event_base *);
  
  static inline void	event_signal_closure(struct event_base *, struct event *ev);
  static inline void	event_persist_closure(struct event_base *, struct event *ev);
  
  static int	evthread_notify_base(struct event_base *base);
  
  static void insert_common_timeout_inorder(struct common_timeout_list *ctl,
      struct event *ev);
  
  #ifndef EVENT__DISABLE_DEBUG_MODE
  /* These functions implement a hashtable of which 'struct event *' structures
   * have been setup or added.  We don't want to trust the content of the struct
   * event itself, since we're trying to work through cases where an event gets
   * clobbered or freed.  Instead, we keep a hashtable indexed by the pointer.
   */
  
  struct event_debug_entry {
  	HT_ENTRY(event_debug_entry) node;
  	const struct event *ptr;
  	unsigned added : 1;
  };
  
  static inline unsigned
  hash_debug_entry(const struct event_debug_entry *e)
  {
  	/* We need to do this silliness to convince compilers that we
  	 * honestly mean to cast e->ptr to an integer, and discard any
  	 * part of it that doesn't fit in an unsigned.
  	 */
  	unsigned u = (unsigned) ((ev_uintptr_t) e->ptr);
  	/* Our hashtable implementation is pretty sensitive to low bits,
  	 * and every struct event is over 64 bytes in size, so we can
  	 * just say >>6. */
  	return (u >> 6);
  }
  
  static inline int
  eq_debug_entry(const struct event_debug_entry *a,
      const struct event_debug_entry *b)
  {
  	return a->ptr == b->ptr;
  }
  
  int event_debug_mode_on_ = 0;
  
  
  #if !defined(EVENT__DISABLE_THREAD_SUPPORT) && !defined(EVENT__DISABLE_DEBUG_MODE)
  /**
   * @brief debug mode variable which is set for any function/structure that needs
   *        to be shared across threads (if thread support is enabled).
   *
   *        When and if evthreads are initialized, this variable will be evaluated,
   *        and if set to something other than zero, this means the evthread setup 
   *        functions were called out of order.
   *
   *        See: "Locks and threading" in the documentation.
   */
  int event_debug_created_threadable_ctx_ = 0;
  #endif
  
  /* Set if it's too late to enable event_debug_mode. */
  static int event_debug_mode_too_late = 0;
  #ifndef EVENT__DISABLE_THREAD_SUPPORT
  static void *event_debug_map_lock_ = NULL;
  #endif
  static HT_HEAD(event_debug_map, event_debug_entry) global_debug_map =
  	HT_INITIALIZER();
  
  HT_PROTOTYPE(event_debug_map, event_debug_entry, node, hash_debug_entry,
      eq_debug_entry)
  HT_GENERATE(event_debug_map, event_debug_entry, node, hash_debug_entry,
      eq_debug_entry, 0.5, mm_malloc, mm_realloc, mm_free)
  
  /* record that ev is now setup (that is, ready for an add) */
  static void event_debug_note_setup_(const struct event *ev)
  {
  	struct event_debug_entry *dent, find;
  
  	if (!event_debug_mode_on_)
  		goto out;
  
  	find.ptr = ev;
  	EVLOCK_LOCK(event_debug_map_lock_, 0);
  	dent = HT_FIND(event_debug_map, &global_debug_map, &find);
  	if (dent) {
  		dent->added = 0;
  	} else {
  		dent = mm_malloc(sizeof(*dent));
  		if (!dent)
  			event_err(1,
  			    "Out of memory in debugging code");
  		dent->ptr = ev;
  		dent->added = 0;
  		HT_INSERT(event_debug_map, &global_debug_map, dent);
  	}
  	EVLOCK_UNLOCK(event_debug_map_lock_, 0);
  
  out:
  	event_debug_mode_too_late = 1;
  }
  /* record that ev is no longer setup */
  static void event_debug_note_teardown_(const struct event *ev)
  {
  	struct event_debug_entry *dent, find;
  
  	if (!event_debug_mode_on_)
  		goto out;
  
  	find.ptr = ev;
  	EVLOCK_LOCK(event_debug_map_lock_, 0);
  	dent = HT_REMOVE(event_debug_map, &global_debug_map, &find);
  	if (dent)
  		mm_free(dent);
  	EVLOCK_UNLOCK(event_debug_map_lock_, 0);
  
  out:
  	event_debug_mode_too_late = 1;
  }
  /* Macro: record that ev is now added */
  static void event_debug_note_add_(const struct event *ev)
  {
  	struct event_debug_entry *dent,find;
  
  	if (!event_debug_mode_on_)
  		goto out;
  
  	find.ptr = ev;
  	EVLOCK_LOCK(event_debug_map_lock_, 0);
  	dent = HT_FIND(event_debug_map, &global_debug_map, &find);
  	if (dent) {
  		dent->added = 1;
  	} else {
  		event_errx(EVENT_ERR_ABORT_,
  		    "%s: noting an add on a non-setup event %p"
  		    " (events: 0x%x, fd: "EV_SOCK_FMT
  		    ", flags: 0x%x)",
  		    __func__, 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
  
  	/* initialize watcher lists */
  	for (i = 0; i < EVWATCH_MAX; ++i)
  		TAILQ_INIT(&base->watchers[i]);
  
  	return (base);
  }
  
  int
  event_base_start_iocp_(struct event_base *base, int n_cpus)
  {
  #ifdef _WIN32
  	if (base->iocp)
  		return 0;
  	base->iocp = event_iocp_port_launch_(n_cpus);
  	if (!base->iocp) {
  		event_warnx("%s: Couldn't launch IOCP", __func__);
  		return -1;
  	}
  	return 0;
  #else
  	return -1;
  #endif
  }
  
  void
  event_base_stop_iocp_(struct event_base *base)
  {
  #ifdef _WIN32
  	int rv;
  
  	if (!base->iocp)
  		return;
  	rv = event_iocp_shutdown_(base->iocp, -1);
  	EVUTIL_ASSERT(rv >= 0);
  	base->iocp = NULL;
  #endif
  }
  
  static int
  event_base_cancel_single_callback_(struct event_base *base,
      struct event_callback *evcb,
      int run_finalizers)
  {
  	int result = 0;
  
  	if (evcb->evcb_flags & EVLIST_INIT) {
  		struct event *ev = event_callback_to_event(evcb);
  		if (!(ev->ev_flags & EVLIST_INTERNAL)) {
  			event_del_(ev, EVENT_DEL_EVEN_IF_FINALIZING);
  			result = 1;
  		}
  	} else {
  		EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  		event_callback_cancel_nolock_(base, evcb, 1);
  		EVBASE_RELEASE_LOCK(base, th_base_lock);
  		result = 1;
  	}
  
  	if (run_finalizers && (evcb->evcb_flags & EVLIST_FINALIZING)) {
  		switch (evcb->evcb_closure) {
  		case EV_CLOSURE_EVENT_FINALIZE:
  		case EV_CLOSURE_EVENT_FINALIZE_FREE: {
  			struct event *ev = event_callback_to_event(evcb);
  			ev->ev_evcallback.evcb_cb_union.evcb_evfinalize(ev, ev->ev_arg);
  			if (evcb->evcb_closure == EV_CLOSURE_EVENT_FINALIZE_FREE)
  				mm_free(ev);
  			break;
  		}
  		case EV_CLOSURE_CB_FINALIZE:
  			evcb->evcb_cb_union.evcb_cbfinalize(evcb, evcb->evcb_arg);
  			break;
  		default:
  			break;
  		}
  	}
  	return result;
  }
  
  static int event_base_free_queues_(struct event_base *base, int run_finalizers)
  {
  	int deleted = 0, i;
  
  	for (i = 0; i < base->nactivequeues; ++i) {
  		struct event_callback *evcb, *next;
  		for (evcb = TAILQ_FIRST(&base->activequeues[i]); evcb; ) {
  			next = TAILQ_NEXT(evcb, evcb_active_next);
  			deleted += event_base_cancel_single_callback_(base, evcb, run_finalizers);
  			evcb = next;
  		}
  	}
  
  	{
  		struct event_callback *evcb;
  		while ((evcb = TAILQ_FIRST(&base->active_later_queue))) {
  			deleted += event_base_cancel_single_callback_(base, evcb, run_finalizers);
  		}
  	}
  
  	return deleted;
  }
  
  static void
  event_base_free_(struct event_base *base, int run_finalizers)
  {
  	int i;
  	size_t n_deleted=0;
  	struct event *ev;
  	struct evwatch *watcher;
  	/* XXXX grab the lock? If there is contention when one thread frees
  	 * the base, then the contending thread will be very sad soon. */
  
  	/* event_base_free(NULL) is how to free the current_base if we
  	 * made it with event_init and forgot to hold a reference to it. */
  	if (base == NULL && current_base)
  		base = current_base;
  	/* Don't actually free NULL. */
  	if (base == NULL) {
  		event_warnx("%s: no base to free", __func__);
  		return;
  	}
  	/* XXX(niels) - check for internal events first */
  
  #ifdef _WIN32
  	event_base_stop_iocp_(base);
  #endif
  
  	/* threading fds if we have them */
  	if (base->th_notify_fd[0] != -1) {
  		event_del(&base->th_notify);
  		EVUTIL_CLOSESOCKET(base->th_notify_fd[0]);
  		if (base->th_notify_fd[1] != -1)
  			EVUTIL_CLOSESOCKET(base->th_notify_fd[1]);
  		base->th_notify_fd[0] = -1;
  		base->th_notify_fd[1] = -1;
  		event_debug_unassign(&base->th_notify);
  	}
  
  	/* Delete all non-internal events. */
  	evmap_delete_all_(base);
  
  	while ((ev = min_heap_top_(&base->timeheap)) != NULL) {
  		event_del(ev);
  		++n_deleted;
  	}
  	for (i = 0; i < base->n_common_timeouts; ++i) {
  		struct common_timeout_list *ctl =
  		    base->common_timeout_queues[i];
  		event_del(&ctl->timeout_event); /* Internal; doesn't count */
  		event_debug_unassign(&ctl->timeout_event);
  		for (ev = TAILQ_FIRST(&ctl->events); ev; ) {
  			struct event *next = TAILQ_NEXT(ev,
  			    ev_timeout_pos.ev_next_with_common_timeout);
  			if (!(ev->ev_flags & EVLIST_INTERNAL)) {
  				event_del(ev);
  				++n_deleted;
  			}
  			ev = next;
  		}
  		mm_free(ctl);
  	}
  	if (base->common_timeout_queues)
  		mm_free(base->common_timeout_queues);
  
  	for (;;) {
  		/* For finalizers we can register yet another finalizer out from
  		 * finalizer, and iff finalizer will be in active_later_queue we can
  		 * add finalizer to activequeues, and we will have events in
  		 * activequeues after this function returns, which is not what we want
  		 * (we even have an assertion for this).
  		 *
  		 * A simple case is bufferevent with underlying (i.e. filters).
  		 */
  		int i = event_base_free_queues_(base, run_finalizers);
  		event_debug(("%s: %d events freed", __func__, i));
  		if (!i) {
  			break;
  		}
  		n_deleted += i;
  	}
  
  	if (n_deleted)
  		event_debug(("%s: "EV_SIZE_FMT" events were still set in base",
  			__func__, n_deleted));
  
  	while (LIST_FIRST(&base->once_events)) {
  		struct event_once *eonce = LIST_FIRST(&base->once_events);
  		LIST_REMOVE(eonce, next_once);
  		mm_free(eonce);
  	}
  
  	if (base->evsel != NULL && base->evsel->dealloc != NULL)
  		base->evsel->dealloc(base);
  
  	for (i = 0; i < base->nactivequeues; ++i)
  		EVUTIL_ASSERT(TAILQ_EMPTY(&base->activequeues[i]));
  
  	EVUTIL_ASSERT(min_heap_empty_(&base->timeheap));
  	min_heap_dtor_(&base->timeheap);
  
  	mm_free(base->activequeues);
  
  	evmap_io_clear_(&base->io);
  	evmap_signal_clear_(&base->sigmap);
  	event_changelist_freemem_(&base->changelist);
  
  	EVTHREAD_FREE_LOCK(base->th_base_lock, 0);
  	EVTHREAD_FREE_COND(base->current_event_cond);
  
  	/* Free all event watchers */
  	for (i = 0; i < EVWATCH_MAX; ++i) {
  		while (!TAILQ_EMPTY(&base->watchers[i])) {
  			watcher = TAILQ_FIRST(&base->watchers[i]);
  			TAILQ_REMOVE(&base->watchers[i], watcher, next);
  			mm_free(watcher);
  		}
  	}
  
  	/* If we're freeing current_base, there won't be a current_base. */
  	if (base == current_base)
  		current_base = NULL;
  	mm_free(base);
  }
  
  void
  event_base_free_nofinalize(struct event_base *base)
  {
  	event_base_free_(base, 0);
  }
  
  void
  event_base_free(struct event_base *base)
  {
  	event_base_free_(base, 1);
  }
  
  /* Fake eventop; used to disable the backend temporarily inside event_reinit
   * so that we can call event_del() on an event without telling the backend.
   */
  static int
  nil_backend_del(struct event_base *b, evutil_socket_t fd, short old,
      short events, void *fdinfo)
  {
  	return 0;
  }
  const struct eventop nil_eventop = {
  	"nil",
  	NULL, /* init: unused. */
  	NULL, /* add: unused. */
  	nil_backend_del, /* del: used, so needs to be killed. */
  	NULL, /* dispatch: unused. */
  	NULL, /* dealloc: unused. */
  	0, 0, 0
  };
  
  /* reinitialize the event base after a fork */
  int
  event_reinit(struct event_base *base)
  {
  	const struct eventop *evsel;
  	int res = 0;
  	int was_notifiable = 0;
  	int had_signal_added = 0;
  
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  
  	evsel = base->evsel;
  
  	/* check if this event mechanism requires reinit on the backend */
  	if (evsel->need_reinit) {
  		/* We're going to call event_del() on our notify events (the
  		 * ones that tell about signals and wakeup events).  But we
  		 * don't actually want to tell the backend to change its
  		 * state, since it might still share some resource (a kqueue,
  		 * an epoll fd) with the parent process, and we don't want to
  		 * delete the fds from _that_ backend, we temporarily stub out
  		 * the evsel with a replacement.
  		 */
  		base->evsel = &nil_eventop;
  	}
  
  	/* We need to re-create a new signal-notification fd and a new
  	 * thread-notification fd.  Otherwise, we'll still share those with
  	 * the parent process, which would make any notification sent to them
  	 * get received by one or both of the event loops, more or less at
  	 * random.
  	 */
  	if (base->sig.ev_signal_added) {
  		event_del_nolock_(&base->sig.ev_signal, EVENT_DEL_AUTOBLOCK);
  		event_debug_unassign(&base->sig.ev_signal);
  		memset(&base->sig.ev_signal, 0, sizeof(base->sig.ev_signal));
  		had_signal_added = 1;
  		base->sig.ev_signal_added = 0;
  	}
  	if (base->sig.ev_signal_pair[0] != -1)
  		EVUTIL_CLOSESOCKET(base->sig.ev_signal_pair[0]);
  	if (base->sig.ev_signal_pair[1] != -1)
  		EVUTIL_CLOSESOCKET(base->sig.ev_signal_pair[1]);
  	if (base->th_notify_fn != NULL) {
  		was_notifiable = 1;
  		base->th_notify_fn = NULL;
  	}
  	if (base->th_notify_fd[0] != -1) {
  		event_del_nolock_(&base->th_notify, EVENT_DEL_AUTOBLOCK);
  		EVUTIL_CLOSESOCKET(base->th_notify_fd[0]);
  		if (base->th_notify_fd[1] != -1)
  			EVUTIL_CLOSESOCKET(base->th_notify_fd[1]);
  		base->th_notify_fd[0] = -1;
  		base->th_notify_fd[1] = -1;
  		event_debug_unassign(&base->th_notify);
  	}
  
  	/* Replace the original evsel. */
          base->evsel = evsel;
  
  	if (evsel->need_reinit) {
  		/* Reconstruct the backend through brute-force, so that we do
  		 * not share any structures with the parent process. For some
  		 * backends, this is necessary: epoll and kqueue, for
  		 * instance, have events associated with a kernel
  		 * structure. If didn't reinitialize, we'd share that
  		 * structure with the parent process, and any changes made by
  		 * the parent would affect our backend's behavior (and vice
  		 * versa).
  		 */
  		if (base->evsel->dealloc != NULL)
  			base->evsel->dealloc(base);
  		base->evbase = evsel->init(base);
  		if (base->evbase == NULL) {
  			event_errx(1,
  			   "%s: could not reinitialize event mechanism",
  			   __func__);
  			res = -1;
  			goto done;
  		}
  
  		/* Empty out the changelist (if any): we are starting from a
  		 * blank slate. */
  		event_changelist_freemem_(&base->changelist);
  
  		/* Tell the event maps to re-inform the backend about all
  		 * pending events. This will make the signal notification
  		 * event get re-created if necessary. */
  		if (evmap_reinit_(base) < 0)
  			res = -1;
  	} else {
  		res = evsig_init_(base);
  		if (res == 0 && had_signal_added) {
  			res = event_add_nolock_(&base->sig.ev_signal, NULL, 0);
  			if (res == 0)
  				base->sig.ev_signal_added = 1;
  		}
  	}
  
  	/* If we were notifiable before, and nothing just exploded, become
  	 * notifiable again. */
  	if (was_notifiable && res == 0)
  		res = evthread_make_base_notifiable_nolock_(base);
  
  done:
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  	return (res);
  }
  
  /* Get the monotonic time for this event_base' timer */
  int
  event_gettime_monotonic(struct event_base *base, struct timeval *tv)
  {
    int rv = -1;
  
    if (base && tv) {
      EVBASE_ACQUIRE_LOCK(base, th_base_lock);
      rv = evutil_gettime_monotonic_(&(base->monotonic_timer), tv);
      EVBASE_RELEASE_LOCK(base, th_base_lock);
    }
  
    return rv;
  }
  
  const char **
  event_get_supported_methods(void)
  {
  	static const char **methods = NULL;
  	const struct eventop **method;
  	const char **tmp;
  	int i = 0, k;
  
  	/* count all methods */
  	for (method = &eventops[0]; *method != NULL; ++method) {
  		++i;
  	}
  
  	/* allocate one more than we need for the NULL pointer */
  	tmp = mm_calloc((i + 1), sizeof(char *));
  	if (tmp == NULL)
  		return (NULL);
  
  	/* populate the array with the supported methods */
  	for (k = 0, i = 0; eventops[k] != NULL; ++k) {
  		tmp[i++] = eventops[k]->name;
  	}
  	tmp[i] = NULL;
  
  	if (methods != NULL)
  		mm_free((char**)methods);
  
  	methods = tmp;
  
  	return (methods);
  }
  
  struct event_config *
  event_config_new(void)
  {
  	struct event_config *cfg = mm_calloc(1, sizeof(*cfg));
  
  	if (cfg == NULL)
  		return (NULL);
  
  	TAILQ_INIT(&cfg->entries);
  	cfg->max_dispatch_interval.tv_sec = -1;
  	cfg->max_dispatch_callbacks = INT_MAX;
  	cfg->limit_callbacks_after_prio = 1;
  
  	return (cfg);
  }
  
  static void
  event_config_entry_free(struct event_config_entry *entry)
  {
  	if (entry->avoid_method != NULL)
  		mm_free((char *)entry->avoid_method);
  	mm_free(entry);
  }
  
  void
  event_config_free(struct event_config *cfg)
  {
  	struct event_config_entry *entry;
  
  	while ((entry = TAILQ_FIRST(&cfg->entries)) != NULL) {
  		TAILQ_REMOVE(&cfg->entries, entry, next);
  		event_config_entry_free(entry);
  	}
  	mm_free(cfg);
  }
  
  int
  event_config_set_flag(struct event_config *cfg, int flag)
  {
  	if (!cfg)
  		return -1;
  	cfg->flags |= flag;
  	return 0;
  }
  
  int
  event_config_avoid_method(struct event_config *cfg, const char *method)
  {
  	struct event_config_entry *entry = mm_malloc(sizeof(*entry));
  	if (entry == NULL)
  		return (-1);
  
  	if ((entry->avoid_method = mm_strdup(method)) == NULL) {
  		mm_free(entry);
  		return (-1);
  	}
  
  	TAILQ_INSERT_TAIL(&cfg->entries, entry, next);
  
  	return (0);
  }
  
  int
  event_config_require_features(struct event_config *cfg,
      int features)
  {
  	if (!cfg)
  		return (-1);
  	cfg->require_features = features;
  	return (0);
  }
  
  int
  event_config_set_num_cpus_hint(struct event_config *cfg, int cpus)
  {
  	if (!cfg)
  		return (-1);
  	cfg->n_cpus_hint = cpus;
  	return (0);
  }
  
  int
  event_config_set_max_dispatch_interval(struct event_config *cfg,
      const struct timeval *max_interval, int max_callbacks, int min_priority)
  {
  	if (max_interval)
  		memcpy(&cfg->max_dispatch_interval, max_interval,
  		    sizeof(struct timeval));
  	else
  		cfg->max_dispatch_interval.tv_sec = -1;
  	cfg->max_dispatch_callbacks =
  	    max_callbacks >= 0 ? max_callbacks : INT_MAX;
  	if (min_priority < 0)
  		min_priority = 0;
  	cfg->limit_callbacks_after_prio = min_priority;
  	return (0);
  }
  
  int
  event_priority_init(int npriorities)
  {
  	return event_base_priority_init(current_base, npriorities);
  }
  
  int
  event_base_priority_init(struct event_base *base, int npriorities)
  {
  	int i, r;
  	r = -1;
  
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  
  	if (N_ACTIVE_CALLBACKS(base) || npriorities < 1
  	    || npriorities >= EVENT_MAX_PRIORITIES)
  		goto err;
  
  	if (npriorities == base->nactivequeues)
  		goto ok;
  
  	if (base->nactivequeues) {
  		mm_free(base->activequeues);
  		base->nactivequeues = 0;
  	}
  
  	/* Allocate our priority queues */
  	base->activequeues = (struct evcallback_list *)
  	  mm_calloc(npriorities, sizeof(struct evcallback_list));
  	if (base->activequeues == NULL) {
  		event_warn("%s: calloc", __func__);
  		goto err;
  	}
  	base->nactivequeues = npriorities;
  
  	for (i = 0; i < base->nactivequeues; ++i) {
  		TAILQ_INIT(&base->activequeues[i]);
  	}
  
  ok:
  	r = 0;
  err:
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  	return (r);
  }
  
  int
  event_base_get_npriorities(struct event_base *base)
  {
  
  	int n;
  	if (base == NULL)
  		base = current_base;
  
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  	n = base->nactivequeues;
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  	return (n);
  }
  
  int
  event_base_get_num_events(struct event_base *base, unsigned int type)
  {
  	int r = 0;
  
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  
  	if (type & EVENT_BASE_COUNT_ACTIVE)
  		r += base->event_count_active;
  
  	if (type & EVENT_BASE_COUNT_VIRTUAL)
  		r += base->virtual_event_count;
  
  	if (type & EVENT_BASE_COUNT_ADDED)
  		r += base->event_count;
  
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  
  	return r;
  }
  
  int
  event_base_get_max_events(struct event_base *base, unsigned int type, int clear)
  {
  	int r = 0;
  
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  
  	if (type & EVENT_BASE_COUNT_ACTIVE) {
  		r += base->event_count_active_max;
  		if (clear)
  			base->event_count_active_max = 0;
  	}
  
  	if (type & EVENT_BASE_COUNT_VIRTUAL) {
  		r += base->virtual_event_count_max;
  		if (clear)
  			base->virtual_event_count_max = 0;
  	}
  
  	if (type & EVENT_BASE_COUNT_ADDED) {
  		r += base->event_count_max;
  		if (clear)
  			base->event_count_max = 0;
  	}
  
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  
  	return r;
  }
  
  /* Returns true iff we're currently watching any events. */
  static int
  event_haveevents(struct event_base *base)
  {
  	/* Caller must hold th_base_lock */
  	return (base->virtual_event_count > 0 || base->event_count > 0);
  }
  
  /* "closure" function called when processing active signal events */
  static inline void
  event_signal_closure(struct event_base *base, struct event *ev)
  {
  	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;
  	struct evwatch_prepare_cb_info prepare_info;
  	struct evwatch_check_cb_info check_info;
  	struct evwatch *watcher;
  
  	/* Grab the lock.  We will release it inside evsel.dispatch, and again
  	 * as we invoke watchers and user callbacks. */
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  
  	if (base->running_loop) {
  		event_warnx("%s: reentrant invocation.  Only one event_base_loop"
  		    " can run on each event_base at once.", __func__);
  		EVBASE_RELEASE_LOCK(base, th_base_lock);
  		return -1;
  	}
  
  	base->running_loop = 1;
  
  	clear_time_cache(base);
  
  	if (base->sig.ev_signal_added && base->sig.ev_n_signals_added)
  		evsig_set_base_(base);
  
  	done = 0;
  
  #ifndef EVENT__DISABLE_THREAD_SUPPORT
  	base->th_owner_id = EVTHREAD_GET_ID();
  #endif
  
  	base->event_gotterm = base->event_break = 0;
  
  	while (!done) {
  		base->event_continue = 0;
  		base->n_deferreds_queued = 0;
  
  		/* Terminate the loop if we have been asked to */
  		if (base->event_gotterm) {
  			break;
  		}
  
  		if (base->event_break) {
  			break;
  		}
  
  		tv_p = &tv;
  		if (!N_ACTIVE_CALLBACKS(base) && !(flags & EVLOOP_NONBLOCK)) {
  			timeout_next(base, &tv_p);
  		} else {
  			/*
  			 * if we have active events, we just poll new events
  			 * without waiting.
  			 */
  			evutil_timerclear(&tv);
  		}
  
  		/* If we have no events, we just exit */
  		if (0==(flags&EVLOOP_NO_EXIT_ON_EMPTY) &&
  		    !event_haveevents(base) && !N_ACTIVE_CALLBACKS(base)) {
  			event_debug(("%s: no events registered.", __func__));
  			retval = 1;
  			goto done;
  		}
  
  		event_queue_make_later_events_active(base);
  
  		/* Invoke prepare watchers before polling for events */
  		prepare_info.timeout = tv_p;
  		TAILQ_FOREACH(watcher, &base->watchers[EVWATCH_PREPARE], next) {
  			EVBASE_RELEASE_LOCK(base, th_base_lock);
  			(*watcher->callback.prepare)(watcher, &prepare_info, watcher->arg);
  			EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  		}
  
  		clear_time_cache(base);
  
  		res = evsel->dispatch(base, tv_p);
  
  		if (res == -1) {
  			event_debug(("%s: dispatch returned unsuccessfully.",
  				__func__));
  			retval = -1;
  			goto done;
  		}
  
  		update_time_cache(base);
  
  		/* Invoke check watchers after polling for events, and before
  		 * processing them */
  		TAILQ_FOREACH(watcher, &base->watchers[EVWATCH_CHECK], next) {
  			EVBASE_RELEASE_LOCK(base, th_base_lock);
  			(*watcher->callback.check)(watcher, &check_info, watcher->arg);
  			EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  		}
  
  		timeout_process(base);
  
  		if (N_ACTIVE_CALLBACKS(base)) {
  			int n = event_process_active(base);
  			if ((flags & EVLOOP_ONCE)
  			    && N_ACTIVE_CALLBACKS(base) == 0
  			    && n != 0)
  				done = 1;
  		} else if (flags & EVLOOP_NONBLOCK)
  			done = 1;
  	}
  	event_debug(("%s: asked to terminate loop.", __func__));
  
  done:
  	clear_time_cache(base);
  	base->running_loop = 0;
  
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  
  	return (retval);
  }
  
  /* One-time callback to implement event_base_once: invokes the user callback,
   * then deletes the allocated storage */
  static void
  event_once_cb(evutil_socket_t fd, short events, void *arg)
  {
  	struct event_once *eonce = arg;
  
  	(*eonce->cb)(fd, events, eonce->arg);
  	EVBASE_ACQUIRE_LOCK(eonce->ev.ev_base, th_base_lock);
  	LIST_REMOVE(eonce, next_once);
  	EVBASE_RELEASE_LOCK(eonce->ev.ev_base, th_base_lock);
  	event_debug_unassign(&eonce->ev);
  	mm_free(eonce);
  }
  
  /* not threadsafe, event scheduled once. */
  int
  event_once(evutil_socket_t fd, short events,
      void (*callback)(evutil_socket_t, short, void *),
      void *arg, const struct timeval *tv)
  {
  	return event_base_once(current_base, fd, events, callback, arg, tv);
  }
  
  /* Schedules an event once */
  int
  event_base_once(struct event_base *base, evutil_socket_t fd, short events,
      void (*callback)(evutil_socket_t, short, void *),
      void *arg, const struct timeval *tv)
  {
  	struct event_once *eonce;
  	int res = 0;
  	int activate = 0;
  
  	if (!base)
  		return (-1);
  
  	/* We cannot support signals that just fire once, or persistent
  	 * events. */
  	if (events & (EV_SIGNAL|EV_PERSIST))
  		return (-1);
  
  	if ((eonce = mm_calloc(1, sizeof(struct event_once))) == NULL)
  		return (-1);
  
  	eonce->cb = callback;
  	eonce->arg = arg;
  
  	if ((events & (EV_TIMEOUT|EV_SIGNAL|EV_READ|EV_WRITE|EV_CLOSED)) == EV_TIMEOUT) {
  		evtimer_assign(&eonce->ev, base, event_once_cb, eonce);
  
  		if (tv == NULL || ! evutil_timerisset(tv)) {
  			/* If the event is going to become active immediately,
  			 * don't put it on the timeout queue.  This is one
  			 * idiom for scheduling a callback, so let's make
  			 * it fast (and order-preserving). */
  			activate = 1;
  		}
  	} else if (events & (EV_READ|EV_WRITE|EV_CLOSED)) {
  		events &= EV_READ|EV_WRITE|EV_CLOSED;
  
  		event_assign(&eonce->ev, base, fd, events, event_once_cb, eonce);
  	} else {
  		/* Bad event combination */
  		mm_free(eonce);
  		return (-1);
  	}
  
  	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;
  	size_t u;
  	struct event *ev;
  
  	/* Start out with all the EVLIST_INSERTED events. */
  	if ((r = evmap_foreach_event_(base, fn, arg)))
  		return r;
  
  	/* Okay, now we deal with those events that have timeouts and are in
  	 * the min-heap. */
  	for (u = 0; u < base->timeheap.n; ++u) {
  		ev = base->timeheap.p[u];
  		if (ev->ev_flags & EVLIST_INSERTED) {
  			/* we already processed this one */
  			continue;
  		}
  		if ((r = fn(base, ev, arg)))
  			return r;
  	}
  
  	/* Now for the events in one of the timeout queues.
  	 * the min-heap. */
  	for (i = 0; i < base->n_common_timeouts; ++i) {
  		struct common_timeout_list *ctl =
  		    base->common_timeout_queues[i];
  		TAILQ_FOREACH(ev, &ctl->events,
  		    ev_timeout_pos.ev_next_with_common_timeout) {
  			if (ev->ev_flags & EVLIST_INSERTED) {
  				/* we already processed this one */
  				continue;
  			}
  			if ((r = fn(base, ev, arg)))
  				return r;
  		}
  	}
  
  	/* Finally, we deal wit all the active events that we haven't touched
  	 * yet. */
  	for (i = 0; i < base->nactivequeues; ++i) {
  		struct event_callback *evcb;
  		TAILQ_FOREACH(evcb, &base->activequeues[i], evcb_active_next) {
  			if ((evcb->evcb_flags & (EVLIST_INIT|EVLIST_INSERTED|EVLIST_TIMEOUT)) != EVLIST_INIT) {
  				/* This isn't an event (evlist_init clear), or
  				 * we already processed it. (inserted or
  				 * timeout set */
  				continue;
  			}
  			ev = event_callback_to_event(evcb);
  			if ((r = fn(base, ev, arg)))
  				return r;
  		}
  	}
  
  	return 0;
  }
  
  /* Helper for event_base_dump_events: called on each event in the event base;
   * dumps only the inserted events. */
  static int
  dump_inserted_event_fn(const struct event_base *base, const struct event *e, void *arg)
  {
  	FILE *output = arg;
  	const char *gloss = (e->ev_events & EV_SIGNAL) ?
  	    "sig" : "fd ";
  
  	if (! (e->ev_flags & (EVLIST_INSERTED|EVLIST_TIMEOUT)))
  		return 0;
  
  	fprintf(output, "  %p [%s "EV_SOCK_FMT"]%s%s%s%s%s%s%s",
  	    (void*)e, gloss, EV_SOCK_ARG(e->ev_fd),
  	    (e->ev_events&EV_READ)?" Read":"",
  	    (e->ev_events&EV_WRITE)?" Write":"",
  	    (e->ev_events&EV_CLOSED)?" EOF":"",
  	    (e->ev_events&EV_SIGNAL)?" Signal":"",
  	    (e->ev_events&EV_PERSIST)?" Persist":"",
  	    (e->ev_events&EV_ET)?" ET":"",
  	    (e->ev_flags&EVLIST_INTERNAL)?" Internal":"");
  	if (e->ev_flags & EVLIST_TIMEOUT) {
  		struct timeval tv;
  		tv.tv_sec = e->ev_timeout.tv_sec;
  		tv.tv_usec = e->ev_timeout.tv_usec & MICROSECONDS_MASK;
  		evutil_timeradd(&tv, &base->tv_clock_diff, &tv);
  		fprintf(output, " Timeout=%ld.%06d",
  		    (long)tv.tv_sec, (int)(tv.tv_usec & MICROSECONDS_MASK));
  	}
  	fputc('\n', output);
  
  	return 0;
  }
  
  /* Helper for event_base_dump_events: called on each event in the event base;
   * dumps only the active events. */
  static int
  dump_active_event_fn(const struct event_base *base, const struct event *e, void *arg)
  {
  	FILE *output = arg;
  	const char *gloss = (e->ev_events & EV_SIGNAL) ?
  	    "sig" : "fd ";
  
  	if (! (e->ev_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER)))
  		return 0;
  
  	fprintf(output, "  %p [%s "EV_SOCK_FMT", priority=%d]%s%s%s%s%s active%s%s\n",
  	    (void*)e, gloss, EV_SOCK_ARG(e->ev_fd), e->ev_pri,
  	    (e->ev_res&EV_READ)?" Read":"",
  	    (e->ev_res&EV_WRITE)?" Write":"",
  	    (e->ev_res&EV_CLOSED)?" EOF":"",
  	    (e->ev_res&EV_SIGNAL)?" Signal":"",
  	    (e->ev_res&EV_TIMEOUT)?" Timeout":"",
  	    (e->ev_flags&EVLIST_INTERNAL)?" [Internal]":"",
  	    (e->ev_flags&EVLIST_ACTIVE_LATER)?" [NextTime]":"");
  
  	return 0;
  }
  
  int
  event_base_foreach_event(struct event_base *base,
      event_base_foreach_event_cb fn, void *arg)
  {
  	int r;
  	if ((!fn) || (!base)) {
  		return -1;
  	}
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  	r = event_base_foreach_event_nolock_(base, fn, arg);
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  	return r;
  }
  
  
  void
  event_base_dump_events(struct event_base *base, FILE *output)
  {
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  	fprintf(output, "Inserted events:\n");
  	event_base_foreach_event_nolock_(base, dump_inserted_event_fn, output);
  
  	fprintf(output, "Active events:\n");
  	event_base_foreach_event_nolock_(base, dump_active_event_fn, output);
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  }
  
  void
  event_base_active_by_fd(struct event_base *base, evutil_socket_t fd, short events)
  {
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  
  	/* Activate any non timer events */
  	if (!(events & EV_TIMEOUT)) {
  		evmap_io_active_(base, fd, events & (EV_READ|EV_WRITE|EV_CLOSED));
  	} else {
  		/* If we want to activate timer events, loop and activate each event with
  		 * the same fd in both the timeheap and common timeouts list */
  		int i;
  		size_t u;
  		struct event *ev;
  
  		for (u = 0; u < base->timeheap.n; ++u) {
  			ev = base->timeheap.p[u];
  			if (ev->ev_fd == fd) {
  				event_active_nolock_(ev, EV_TIMEOUT, 1);
  			}
  		}
  
  		for (i = 0; i < base->n_common_timeouts; ++i) {
  			struct common_timeout_list *ctl = base->common_timeout_queues[i];
  			TAILQ_FOREACH(ev, &ctl->events,
  				ev_timeout_pos.ev_next_with_common_timeout) {
  				if (ev->ev_fd == fd) {
  					event_active_nolock_(ev, EV_TIMEOUT, 1);
  				}
  			}
  		}
  	}
  
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  }
  
  void
  event_base_active_by_signal(struct event_base *base, int sig)
  {
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  	evmap_signal_active_(base, sig, 1);
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  }
  
  
  void
  event_base_add_virtual_(struct event_base *base)
  {
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  	base->virtual_event_count++;
  	MAX_EVENT_COUNT(base->virtual_event_count_max, base->virtual_event_count);
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  }
  
  void
  event_base_del_virtual_(struct event_base *base)
  {
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  	EVUTIL_ASSERT(base->virtual_event_count > 0);
  	base->virtual_event_count--;
  	if (base->virtual_event_count == 0 && EVBASE_NEED_NOTIFY(base))
  		evthread_notify_base(base);
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  }
  
  static void
  event_free_debug_globals_locks(void)
  {
  #ifndef EVENT__DISABLE_THREAD_SUPPORT
  #ifndef EVENT__DISABLE_DEBUG_MODE
  	if (event_debug_map_lock_ != NULL) {
  		EVTHREAD_FREE_LOCK(event_debug_map_lock_, 0);
  		event_debug_map_lock_ = NULL;
  		evthreadimpl_disable_lock_debugging_();
  	}
  #endif /* EVENT__DISABLE_DEBUG_MODE */
  #endif /* EVENT__DISABLE_THREAD_SUPPORT */
  	return;
  }
  
  static void
  event_free_debug_globals(void)
  {
  	event_free_debug_globals_locks();
  }
  
  static void
  event_free_evsig_globals(void)
  {
  	evsig_free_globals_();
  }
  
  static void
  event_free_evutil_globals(void)
  {
  	evutil_free_globals_();
  }
  
  static void
  event_free_globals(void)
  {
  	event_free_debug_globals();
  	event_free_evsig_globals();
  	event_free_evutil_globals();
  }
  
  void
  libevent_global_shutdown(void)
  {
  	event_disable_debug_mode();
  	event_free_globals();
  }
  
  #ifndef EVENT__DISABLE_THREAD_SUPPORT
  int
  event_global_setup_locks_(const int enable_locks)
  {
  #ifndef EVENT__DISABLE_DEBUG_MODE
  	EVTHREAD_SETUP_GLOBAL_LOCK(event_debug_map_lock_, 0);
  #endif
  	if (evsig_global_setup_locks_(enable_locks) < 0)
  		return -1;
  	if (evutil_global_setup_locks_(enable_locks) < 0)
  		return -1;
  	if (evutil_secure_rng_global_setup_locks_(enable_locks) < 0)
  		return -1;
  	return 0;
  }
  #endif
  
  void
  event_base_assert_ok_(struct event_base *base)
  {
  	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
  	event_base_assert_ok_nolock_(base);
  	EVBASE_RELEASE_LOCK(base, th_base_lock);
  }
  
  void
  event_base_assert_ok_nolock_(struct event_base *base)
  {
  	int i;
  	size_t u;
  	int count;
  
  	/* First do checks on the per-fd and per-signal lists */
  	evmap_check_integrity_(base);
  
  	/* Check the heap property */
  	for (u = 1; u < base->timeheap.n; ++u) {
  		size_t parent = (u - 1) / 2;
  		struct event *ev, *p_ev;
  		ev = base->timeheap.p[u];
  		p_ev = base->timeheap.p[parent];
  		EVUTIL_ASSERT(ev->ev_flags & EVLIST_TIMEOUT);
  		EVUTIL_ASSERT(evutil_timercmp(&p_ev->ev_timeout, &ev->ev_timeout, <=));
  		EVUTIL_ASSERT(ev->ev_timeout_pos.min_heap_idx == u);
  	}
  
  	/* Check that the common timeouts are fine */
  	for (i = 0; i < base->n_common_timeouts; ++i) {
  		struct common_timeout_list *ctl = base->common_timeout_queues[i];
  		struct event *last=NULL, *ev;
  
  		EVUTIL_ASSERT_TAILQ_OK(&ctl->events, event, ev_timeout_pos.ev_next_with_common_timeout);
  
  		TAILQ_FOREACH(ev, &ctl->events, ev_timeout_pos.ev_next_with_common_timeout) {
  			if (last)
  				EVUTIL_ASSERT(evutil_timercmp(&last->ev_timeout, &ev->ev_timeout, <=));
  			EVUTIL_ASSERT(ev->ev_flags & EVLIST_TIMEOUT);
  			EVUTIL_ASSERT(is_common_timeout(&ev->ev_timeout,base));
  			EVUTIL_ASSERT(COMMON_TIMEOUT_IDX(&ev->ev_timeout) == i);
  			last = ev;
  		}
  	}
  
  	/* Check the active queues. */
  	count = 0;
  	for (i = 0; i < base->nactivequeues; ++i) {
  		struct event_callback *evcb;
  		EVUTIL_ASSERT_TAILQ_OK(&base->activequeues[i], event_callback, evcb_active_next);
  		TAILQ_FOREACH(evcb, &base->activequeues[i], evcb_active_next) {
  			EVUTIL_ASSERT((evcb->evcb_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER)) == EVLIST_ACTIVE);
  			EVUTIL_ASSERT(evcb->evcb_pri == i);
  			++count;
  		}
  	}
  
  	{
  		struct event_callback *evcb;
  		TAILQ_FOREACH(evcb, &base->active_later_queue, evcb_active_next) {
  			EVUTIL_ASSERT((evcb->evcb_flags & (EVLIST_ACTIVE|EVLIST_ACTIVE_LATER)) == EVLIST_ACTIVE_LATER);
  			++count;
  		}
  	}
  	EVUTIL_ASSERT(count == base->event_count_active);
  }
  