108 lines
2.7 KiB
C
108 lines
2.7 KiB
C
/*
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* Copyright (C) 2000, 2001, 2004-2007, 2016 Internet Systems Consortium, Inc. ("ISC")
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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/* $Id: ondestroy.h,v 1.14 2007/06/19 23:47:18 tbox Exp $ */
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#ifndef ISC_ONDESTROY_H
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#define ISC_ONDESTROY_H 1
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#include <isc/lang.h>
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#include <isc/types.h>
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ISC_LANG_BEGINDECLS
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/*! \file isc/ondestroy.h
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* ondestroy handling.
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*
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* Any class ``X'' of objects that wants to send out notifications
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* on its destruction should declare a field of type isc_ondestroy_t
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* (call it 'ondest').
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*
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* \code
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* typedef struct {
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* ...
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* isc_ondestroy_t ondest;
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* ...
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* } X;
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* \endcode
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*
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* When an object ``A'' of type X is created
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* it must initialize the field ondest with a call to
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*
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* \code
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* isc_ondestroy_init(&A->ondest).
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* \endcode
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*
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* X should also provide a registration function for third-party
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* objects to call to register their interest in being told about
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* the destruction of a particular instance of X.
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*
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* \code
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* isc_result_t
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* X_ondestroy(X *instance, isc_task_t *task,
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* isc_event_t **eventp) {
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* return(isc_ondestroy_register(&instance->ondest, task,eventp));
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* }
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* \endcode
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*
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* Note: locking of the ondestory structure embedded inside of X, is
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* X's responsibility.
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*
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* When an instance of X is destroyed, a call to isc_ondestroy_notify()
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* sends the notifications:
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*
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* \code
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* X *instance;
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* isc_ondestroy_t ondest = instance->ondest;
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*
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* ... completely cleanup 'instance' here...
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*
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* isc_ondestroy_notify(&ondest, instance);
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* \endcode
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*
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*
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* see lib/dns/zone.c for an ifdef'd-out example.
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*/
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struct isc_ondestroy {
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unsigned int magic;
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isc_eventlist_t events;
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};
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void
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isc_ondestroy_init(isc_ondestroy_t *ondest);
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/*%<
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* Initialize the on ondest structure. *must* be called before first call
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* to isc_ondestroy_register().
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*/
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isc_result_t
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isc_ondestroy_register(isc_ondestroy_t *ondest, isc_task_t *task,
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isc_event_t **eventp);
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/*%<
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* Stores task and *eventp away inside *ondest. Ownership of **event is
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* taken from the caller (and *eventp is set to NULL). The task is attached
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* to.
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*/
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void
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isc_ondestroy_notify(isc_ondestroy_t *ondest, void *sender);
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/*%<
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* Dispatches the event(s) to the task(s) that were given in
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* isc_ondestroy_register call(s) (done via calls to
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* isc_task_sendanddetach()). Before dispatch, the sender value of each
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* event structure is set to the value of the sender paramater. The
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* internal structures of the ondest parameter are cleaned out, so no other
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* cleanup is needed.
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*/
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ISC_LANG_ENDDECLS
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#endif /* ISC_ONDESTROY_H */
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