/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * 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.
 */

#ifndef ISC_EVENT_H
#define ISC_EVENT_H 1

/*! \file isc/event.h */

#include <isc/types.h>

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

typedef void (*isc_eventdestructor_t)(isc_event_t *);

#define ISC_EVENT_COMMON(ltype)         \
        size_t                          ev_size; \
        unsigned int                    ev_attributes; \
        void *                          ev_tag; \
        isc_eventtype_t                 ev_type; \
        isc_taskaction_t                ev_action; \
        void *                          ev_arg; \
        void *                          ev_sender; \
        isc_eventdestructor_t           ev_destroy; \
        void *                          ev_destroy_arg; \
        ISC_LINK(ltype)                 ev_link; \
        ISC_LINK(ltype)                 ev_ratelink

/*%
 * Attributes matching a mask of 0x000000ff are reserved for the task library's
 * definition.  Attributes of 0xffffff00 may be used by the application
 * or non-ISC libraries.
 */
#define ISC_EVENTATTR_NOPURGE           0x00000001

/*%
 * The ISC_EVENTATTR_CANCELED attribute is intended to indicate
 * that an event is delivered as a result of a canceled operation
 * rather than successful completion, by mutual agreement
 * between the sender and receiver.  It is not set or used by
 * the task system.
 */
#define ISC_EVENTATTR_CANCELED          0x00000002

#define ISC_EVENT_INIT(event, sz, at, ta, ty, ac, ar, sn, df) \
do { \
        (event)->ev_size = (sz); \
        (event)->ev_attributes = (at); \
        (event)->ev_tag = (ta); \
        (event)->ev_type = (ty); \
        (event)->ev_action = (ac); \
        (event)->ev_arg = (ar); \
        (event)->ev_sender = (sn); \
        (event)->ev_destroy = (df); \
        ISC_LINK_INIT((event), ev_link); \
        ISC_LINK_INIT((event), ev_ratelink); \
} while (0)

/*%
 * This structure is public because "subclassing" it may be useful when
 * defining new event types.
 */
struct isc_event {
        ISC_EVENT_COMMON(struct isc_event);
};

#define ISC_EVENTTYPE_FIRSTEVENT        0x00000000
#define ISC_EVENTTYPE_LASTEVENT         0xffffffff

#define ISC_EVENT_PTR(p) ((isc_event_t **)(void *)(p))

isc_event_t *
isc_event_allocate(void *sender, isc_eventtype_t type,
                   isc_taskaction_t action, void *arg, size_t size);
/*%<
 * Allocate an event structure.
 *
 * Allocate and initialize in a structure with initial elements
 * defined by:
 *
 * \code
 *      struct {
 *              ISC_EVENT_COMMON(struct isc_event);
 *              ...
 *      };
 * \endcode
 *
 * Requires:
 *\li   'size' >= sizeof(struct isc_event)
 *\li   'action' to be non NULL
 *
 * Returns:
 *\li   a pointer to a initialized structure of the requested size.
 *\li   NULL if unable to allocate memory.
 */

void
isc_event_free(isc_event_t **);

#endif /* ISC_EVENT_H */