/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, you can obtain one at https://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/

#ifndef ISC_EVENT_H
#define ISC_EVENT_H 1

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

#include <isc/lang.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, da) \
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); \
(event)->ev_destroy_arg = (da); \
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_LANG_BEGINDECLS

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

ISC_LANG_ENDDECLS

#endif /* ISC_EVENT_H */