Current File : //usr/include/bind9/isc/ondestroy.h
/*
* 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_ONDESTROY_H
#define ISC_ONDESTROY_H 1
#include <isc/lang.h>
#include <isc/types.h>
ISC_LANG_BEGINDECLS
/*! \file isc/ondestroy.h
* ondestroy handling.
*
* Any class ``X'' of objects that wants to send out notifications
* on its destruction should declare a field of type isc_ondestroy_t
* (call it 'ondest').
*
* \code
* typedef struct {
* ...
* isc_ondestroy_t ondest;
* ...
* } X;
* \endcode
*
* When an object ``A'' of type X is created
* it must initialize the field ondest with a call to
*
* \code
* isc_ondestroy_init(&A->ondest).
* \endcode
*
* X should also provide a registration function for third-party
* objects to call to register their interest in being told about
* the destruction of a particular instance of X.
*
* \code
* isc_result_t
* X_ondestroy(X *instance, isc_task_t *task,
* isc_event_t **eventp) {
* return(isc_ondestroy_register(&instance->ondest, task,eventp));
* }
* \endcode
*
* Note: locking of the ondestory structure embedded inside of X, is
* X's responsibility.
*
* When an instance of X is destroyed, a call to isc_ondestroy_notify()
* sends the notifications:
*
* \code
* X *instance;
* isc_ondestroy_t ondest = instance->ondest;
*
* ... completely cleanup 'instance' here...
*
* isc_ondestroy_notify(&ondest, instance);
* \endcode
*
*
* see lib/dns/zone.c for an ifdef'd-out example.
*/
struct isc_ondestroy {
unsigned int magic;
isc_eventlist_t events;
};
void
isc_ondestroy_init(isc_ondestroy_t *ondest);
/*%<
* Initialize the on ondest structure. *must* be called before first call
* to isc_ondestroy_register().
*/
isc_result_t
isc_ondestroy_register(isc_ondestroy_t *ondest, isc_task_t *task,
isc_event_t **eventp);
/*%<
* Stores task and *eventp away inside *ondest. Ownership of **event is
* taken from the caller (and *eventp is set to NULL). The task is attached
* to.
*/
void
isc_ondestroy_notify(isc_ondestroy_t *ondest, void *sender);
/*%<
* Dispatches the event(s) to the task(s) that were given in
* isc_ondestroy_register call(s) (done via calls to
* isc_task_sendanddetach()). Before dispatch, the sender value of each
* event structure is set to the value of the sender parameter. The
* internal structures of the ondest parameter are cleaned out, so no other
* cleanup is needed.
*/
ISC_LANG_ENDDECLS
#endif /* ISC_ONDESTROY_H */
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