lib/isc/event.c

	event.c revision 9c3531d72aeaad6c5f01efe6a1c82023e1379e4d
/*
 * Copyright (C) 1998-2000  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/* $Id: event.c,v 1.11 2000/06/22 21:56:54 tale Exp $ */

/*
 * Principal Author: Bob Halley
 */

#include <config.h>

#include <isc/event.h>
#include <isc/mem.h>
#include <isc/util.h>

/***
 *** Events.
 ***/

static void
destroy(isc_event_t *event) {
    isc_mem_t *mctx = event->ev_destroy_arg;

    isc_mem_put(mctx, event, event->ev_size);
}

isc_event_t *
isc_event_allocate(isc_mem_t *mctx, void *sender, isc_eventtype_t type,
           isc_taskaction_t action, const void *arg, size_t size)
{
    isc_event_t *event;
    void *deconst_arg;

    if (size < sizeof (struct isc_event))
        return (NULL);
    if (action == NULL)
        return (NULL);

    event = isc_mem_get(mctx, size);
    if (event == NULL)
        return (NULL);

    /*
     * Removing the const attribute from "arg" is the best of two
     * evils here.  If the event->ev_arg member is made const, then
     * it affects a great many users of the task/event subsystem
     * which are not passing in an "arg" which starts its life as
     * const.  Changing isc_event_allocate() and isc_task_onshutdown()
     * to not have "arg" prototyped as const (which is quite legitimate,
     * because neither of those functions modify arg) can cause
     * compiler whining anytime someone does want to use a const
     * arg that they themselves never modify, such as with
     * gcc -Wwrite-strings and using a string "arg".
     */
    DE_CONST(arg, deconst_arg);

    ISC_EVENT_INIT(event, size, 0, NULL, type, action, deconst_arg,
               sender, destroy, mctx);

    return (event);
}

void
isc_event_free(isc_event_t **eventp) {
    isc_event_t *event;

    REQUIRE(eventp != NULL);
    event = *eventp;
    REQUIRE(event != NULL);

    if (event->ev_destroy != NULL)
        (event->ev_destroy)(event);

    *eventp = NULL;
}