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/*
* mini-event.h - micro implementation of libevent api, using select() only.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 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.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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 COPYRIGHT
* HOLDER OR CONTRIBUTORS 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.
*/
/**
* \file
* This file implements part of the event(3) libevent api.
* The back end is only select. Max number of fds is limited.
* Max number of signals is limited, one handler per signal only.
* And one handler per fd.
*
* Although limited to select() and a max (1024) open fds, it
* is efficient:
* o dispatch call caches fd_sets to use.
* o handler calling takes time ~ to the number of fds.
* o timeouts are stored in a redblack tree, sorted, so take log(n).
* Timeouts are only accurate to the second (no subsecond accuracy).
* To avoid cpu hogging, fractional timeouts are rounded up to a whole second.
*/
#ifndef MINI_EVENT_H
#define MINI_EVENT_H
struct region;
#if defined(USE_MINI_EVENT) && !defined(USE_WINSOCK)
#ifdef HAVE_SYS_SELECT_H
/* for fd_set on OpenBSD */
#include <sys/select.h>
#endif
#ifndef HAVE_EVENT_BASE_FREE
#define HAVE_EVENT_BASE_FREE
#endif
/** event timeout */
#define EV_TIMEOUT 0x01
/** event fd readable */
#define EV_READ 0x02
/** event fd writable */
#define EV_WRITE 0x04
/** event signal */
#define EV_SIGNAL 0x08
/** event must persist */
#define EV_PERSIST 0x10
/* needs our redblack tree */
#include "rbtree.h"
/** max number of file descriptors to support */
#define MAX_FDS 1024
/** max number of signals to support */
#define MAX_SIG 32
/** event base */
struct event_base
{
/** sorted by timeout (absolute), ptr */
rbtree_type* times;
/** array of 0 - maxfd of ptr to event for it */
struct event** fds;
/** max fd in use */
int maxfd;
/** capacity - size of the fds array */
int capfd;
/* fdset for read write, for fds ready, and added */
fd_set
/** fds for reading */
reads,
/** fds for writing */
writes,
/** fds determined ready for use */
ready,
/** ready plus newly added events. */
content;
/** array of 0 - maxsig of ptr to event for it */
struct event** signals;
/** if we need to exit */
int need_to_exit;
/** where to store time in seconds */
time_t* time_secs;
/** where to store time in microseconds */
struct timeval* time_tv;
/** region for allocation */
struct region* region;
};
/**
* Event structure. Has some of the event elements.
*/
struct event {
/** node in timeout rbtree */
rbnode_type node;
/** is event already added */
int added;
/** event base it belongs to */
struct event_base *ev_base;
/** fd to poll or -1 for timeouts. signal number for sigs. */
int ev_fd;
/** what events this event is interested in, see EV_.. above. */
short ev_flags;
/** timeout value */
struct timeval ev_timeout;
/** callback to call: fd, eventbits, userarg */
void (*ev_callback)(int, short, void *arg);
/** callback user arg */
void *ev_arg;
};
/* function prototypes (some are as they appear in event.h) */
/** create event base */
void *event_init(time_t* time_secs, struct timeval* time_tv);
/** get version */
const char *event_get_version(void);
/** get polling method, select */
const char *event_get_method(void);
/** run select in a loop */
int event_base_dispatch(struct event_base *);
/** exit that loop */
int event_base_loopexit(struct event_base *, struct timeval *);
/** run select once */
#define EVLOOP_ONCE 1
int event_base_loop(struct event_base* base, int flags);
/** free event base. Free events yourself */
void event_base_free(struct event_base *);
/** set content of event */
void event_set(struct event *, int, short, void (*)(int, short, void *), void *);
/** add event to a base. You *must* call this for every event. */
int event_base_set(struct event_base *, struct event *);
/** add event to make it active. You may not change it with event_set anymore */
int event_add(struct event *, struct timeval *);
/** remove event. You may change it again */
int event_del(struct event *);
/** add a timer */
#define evtimer_add(ev, tv) event_add(ev, tv)
/** remove a timer */
#define evtimer_del(ev) event_del(ev)
/* uses different implementation. Cannot mix fd/timeouts and signals inside
* the same struct event. create several event structs for that. */
/** install signal handler */
int signal_add(struct event *, struct timeval *);
/** set signal event contents */
#define signal_set(ev, x, cb, arg) \
event_set(ev, x, EV_SIGNAL|EV_PERSIST, cb, arg)
/** remove signal handler */
int signal_del(struct event *);
#endif /* USE_MINI_EVENT and not USE_WINSOCK */
/** compare events in tree, based on timevalue, ptr for uniqueness */
int mini_ev_cmp(const void* a, const void* b);
#endif /* MINI_EVENT_H */
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