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-rw-r--r-- | external/unbound/util/mini_event.h | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/external/unbound/util/mini_event.h b/external/unbound/util/mini_event.h new file mode 100644 index 000000000..58bbc8073 --- /dev/null +++ b/external/unbound/util/mini_event.h @@ -0,0 +1,177 @@ +/* + * 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 + +#if defined(USE_MINI_EVENT) && !defined(USE_WINSOCK) + +#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_t* 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; +}; + +/** + * Event structure. Has some of the event elements. + */ +struct event { + /** node in timeout rbtree */ + rbnode_t 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_events; + /** 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 *); +/** 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 */ |