Supporting type and routines for ondestroy event notifcation.

lib/isc/include/isc/ondestroy.h

@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2000  Internet Software Consortium.
+ * 
+ * Permission to use, copy, modify, and 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM 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_ONDESTROY_H
+#define ISC_ONDESTROY_H 1
+
+#include <stddef.h>
+
+#include <isc/event.h>
+
+ISC_LANG_BEGINDECLS
+
+/*
+ * 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'). 
+ *
+ * 	typedef struct {
+ * 		...
+ * 		isc_ondestroy_t	ondest;
+ * 		...
+ * 	} X;
+ *
+ * When an object ``A'' of type X is created
+ * it must initialize the field ondest with a call to
+ *
+ * 	isc_ondestroy_init(&A->ondest). 
+ *
+ * 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.
+ *
+ *	isc_result_t
+ * 	X_ondestroy(X *instance, isc_task_t *task, 
+ * 		     isc_event_t **eventp) {
+ * 		return(isc_ondestroy_register(&instance->ondest, task,eventp));
+ * 	}
+ *
+ *	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:
+ *
+ *	X *instance;
+ *	isc_ondestroy_t ondest = instance->ondest;
+ *
+ *	... completely cleanup 'instance' here...
+ *
+ * 	isc_ondestroy_notify(&ondest, instance);
+ *
+ *
+ * see dns/zone.c for an ifdef'd-out example.
+ */
+
+typedef struct {
+	unsigned int magic;
+	isc_eventlist_t events;
+} isc_ondestroy_t;
+
+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 paramater. The
+ * internal structures of the ondest parameter are cleaned out, so no other
+ * cleanup is needed.
+ */
+
+ISC_LANG_ENDDECLS
+
+#endif /* ISC_ONDESTROY_H */

lib/isc/ondestroy.c

@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2000  Internet Software Consortium.
+ * 
+ * Permission to use, copy, modify, and 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM 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.
+ */
+
+#include <config.h>
+
+#include <isc/assertions.h>
+#include <isc/ondestroy.h>
+#include <isc/result.h>
+#include <isc/task.h>
+
+#define ONDESTROY_MAGIC		0x44655374 /* DeSt */
+#define VALID_ONDESTROY(s)	(s != NULL && (s->magic == ONDESTROY_MAGIC))
+
+void
+isc_ondestroy_init(isc_ondestroy_t *ondest)
+{
+	ondest->magic = ONDESTROY_MAGIC;
+	ISC_LIST_INIT(ondest->events);
+}
+
+
+isc_result_t
+isc_ondestroy_register(isc_ondestroy_t *ondest,
+		       isc_task_t *task, isc_event_t **eventp)
+{
+	isc_event_t *theevent;
+	isc_task_t *thetask = NULL;
+
+	REQUIRE(VALID_ONDESTROY(ondest));
+	REQUIRE(task != NULL);
+	REQUIRE(eventp != NULL);
+
+	theevent = *eventp;
+
+	REQUIRE(theevent != NULL);
+
+	isc_task_attach(task, &thetask);
+
+	theevent->sender = thetask;
+	
+	ISC_LIST_APPEND(ondest->events, theevent, link);
+
+	return (ISC_R_SUCCESS);
+}
+
+
+
+void
+isc_ondestroy_notify(isc_ondestroy_t *ondest, void *sender)
+{
+	isc_event_t *eventp;
+	isc_task_t *task;
+	
+	REQUIRE(VALID_ONDESTROY(ondest));
+
+	eventp = ISC_LIST_HEAD(ondest->events);
+	while (eventp != NULL) {
+		ISC_LIST_UNLINK(ondest->events, eventp, link);
+
+		task = eventp->sender;
+		eventp->sender = sender;
+		
+		isc_task_sendanddetach(&task, &eventp);
+
+		eventp = ISC_LIST_HEAD(ondest->events);
+	}
+}
+
+