lib/isc/event.c

	event.c revision 70e5a7403f0e0a3bd292b8287c5fed5772c15270
/*
 * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1998-2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or 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 ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC 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 1.21 2007/06/19 23:47:17 tbox Exp $ */

/*!
 * \file
 * \author 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;

    REQUIRE(size >= sizeof(struct isc_event));
    REQUIRE(action != 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;
}