/*
 * Copyright (C) 1996, 1997, 1998, 1999  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.
 */

/* $Id: dispatch.c,v 1.6 2000/01/11 01:49:23 tale Exp $ */

/* Principal Author: Ted Lemon */

/*
 * I/O dispatcher.
 */
#include <stddef.h>		/* NULL */
#include <string.h>		/* memset */

#include <isc/assertions.h>
#include <isc/int.h>

#include <omapi/private.h>

typedef struct omapi_io_object {
	OMAPI_OBJECT_PREAMBLE;
	struct omapi_io_object *	next;
	int 				(*readfd) (omapi_object_t *);
	int 				(*writefd)(omapi_object_t *);
	isc_result_t			(*reader) (omapi_object_t *);
	isc_result_t			(*writer) (omapi_object_t *);
	isc_result_t			(*reaper) (omapi_object_t *);
} omapi_io_object_t;

typedef struct omapi_waiter_object {
	OMAPI_OBJECT_PREAMBLE;
	struct omapi_waiter_object *	next;
	int				ready;
} omapi_waiter_object_t;

static omapi_io_object_t omapi_io_states;
isc_uint32_t cur_time;

isc_result_t
omapi_dispatch(struct timeval *t) {
	/*
	 * XXXDCL sleep forever?  The socket thread will be doing all the work.
	 */

	select(0, NULL, NULL, NULL, t ? t : NULL);
	return (ISC_R_SUCCESS);
}

isc_result_t
omapi_wait_for_completion(omapi_object_t *object, struct timeval *t) {
	isc_result_t result;
	omapi_waiter_object_t *waiter = NULL;
	omapi_object_t *inner;

	if (object != NULL) {
		result = omapi_object_new((omapi_object_t **)&waiter,
					  omapi_type_waiter, sizeof(*waiter));
		if (result != ISC_R_SUCCESS)
			return (result);

		/*
		 * Paste the waiter object onto the inner object we're
		 * waiting on.
		 */
		for (inner = object; inner->inner != NULL;
		     inner = inner->inner)
			;

		OBJECT_REF(&waiter->outer, inner, "omapi_wait_for_completion");
		OBJECT_REF(&inner->inner, waiter, "omapi_wait_for_completion");
	} else
		waiter = NULL;

	do {
		result = omapi_one_dispatch((omapi_object_t *)waiter, t);
		if (result != ISC_R_SUCCESS)
			return (result);
	} while (waiter == NULL || waiter->ready == 0);

	if (waiter->outer != NULL) {
		if (waiter->outer->inner != NULL) {
			OBJECT_DEREF(&waiter->outer->inner,
				    "omapi_wait_for_completion");
			if (waiter->inner != NULL)
				OBJECT_REF(&waiter->outer->inner, waiter->inner,
					  "omapi_wait_for_completion");
		}
		OBJECT_DEREF(&waiter->outer, "omapi_wait_for_completion");
	}
	if (waiter->inner != NULL)
		OBJECT_DEREF(&waiter->inner, "omapi_wait_for_completion");
	
	OBJECT_DEREF(&waiter, "omapi_wait_for_completion");

	return (ISC_R_SUCCESS);
}

isc_result_t
omapi_one_dispatch(omapi_object_t *wo, struct timeval *t) {
	fd_set r, w, x;
	int count;
	int desc;
	int max = 0;
	struct timeval now, to;
	omapi_io_object_t *io, *prev;
	isc_result_t result;
	omapi_waiter_object_t *waiter;

	if (wo == NULL || wo->type != omapi_type_waiter)
		waiter = NULL;
	else
		waiter = (omapi_waiter_object_t *)wo;

	FD_ZERO(&r);
	FD_ZERO(&w);
	FD_ZERO(&x);

	/*
	 * First, see if the timeout has expired, and if so return.
	 */
	if (t != NULL) {
		gettimeofday(&now, NULL);
		cur_time = now.tv_sec;
		if (now.tv_sec > t->tv_sec ||
		    (now.tv_sec == t->tv_sec && now.tv_usec >= t->tv_usec))
			return (ISC_R_TIMEDOUT);
			
		/*
		 * We didn't time out, so figure out how long until we do.
		 */
		to.tv_sec = t->tv_sec - now.tv_sec;
		to.tv_usec = t->tv_usec - now.tv_usec;
		if (to.tv_usec < 0) {
			to.tv_usec += 1000000;
			to.tv_sec--;
		}
	}

	/*
	 * If the object we're waiting on has reached completion,
	 * return now.
	 */
	if (waiter != NULL && waiter->ready != 0)
		return (ISC_R_SUCCESS);

	/*
	 * If we have no I/O state, we can't proceed.
	 */
	io = omapi_io_states.next;
	if (io == NULL)
		return (ISC_R_NOMORE);

	/*
	 * Set up the read and write masks.
	 */
	for (; io != NULL; io = io->next) {
		/*
		 * Check for a read socket.   If we shouldn't be
		 * trying to read for this I/O object, either there
		 * won't be a readfd function, or it'll return -1.
		 */
		if (io->readfd != NULL) {
			desc = (*(io->readfd))(io->inner);
			FD_SET(desc, &r);
			if (desc > max)
				max = desc;
		}
		
		/*
		 * Same deal for write fdsets.
		 */
		if (io->writefd != NULL) {
			desc = (*(io->writefd))(io->inner);
			FD_SET(desc, &w);
			if (desc > max)
				max = desc;
		}
	}

	/*
	 * Wait for a packet or a timeout. XXXTL
	 */
	count = select(max + 1, &r, &w, &x, t ? &to : NULL);

	/*
	 * Get the current time.
	 */
	gettimeofday(&now, NULL);
	cur_time = now.tv_sec;

	/*
	 * Not likely to be transitory.
	 */
	if (count < 0)
		return (ISC_R_UNEXPECTED);

	for (io = omapi_io_states.next; io != NULL; io = io->next) {
		/*
		 * Check for a read descriptor, and if there is one,
		 * see if we got input on that socket.
		 */
		if (io->readfd != NULL &&
		    (desc = (*(io->readfd))(io->inner)) >= 0) {
			if (FD_ISSET(desc, &r))
				result = (*(io->reader))(io->inner);
				/* XXXTL what to do with result? */
		}
		
		/*
		 * Same deal for write descriptors.
		 */
		if (io->writefd != NULL &&
		    (desc = (*(io->writefd))(io->inner)) >= 0) {
			if (FD_ISSET(desc, &w))
				result = (*(io->writer))(io->inner);
				/* XXX what to do with result? */
		}
	}

	/*
	 * Now check for I/O handles that are no longer valid,
	 * and remove them from the list.
	 */
	prev = NULL;
	for (io = omapi_io_states.next; io != NULL; io = io->next) {
		if (io->reaper != NULL) {
			result = (*(io->reaper))(io->inner);
			if (result != ISC_R_SUCCESS) {
				omapi_io_object_t *tmp = NULL;
				/*
				 * Save a reference to the next
				 * pointer, if there is one.
				 */
				if (io->next != NULL)
					OBJECT_REF(&tmp, io->next, "omapi_wfc");
				if (prev != NULL) {
					OBJECT_DEREF(&prev->next, "omapi_wfc");
					if (tmp != NULL)
						OBJECT_REF(&prev->next, tmp,
							  "omapi_wfc");
				} else {
					OBJECT_DEREF(&omapi_io_states.next,
						    "omapi_wfc");
					if (tmp != NULL)
						OBJECT_REF(&omapi_io_states.next,
							  tmp, "omapi_wfc");
					else
						omapi_signal_in
							((omapi_object_t *)
							 &omapi_io_states,
							 "ready");
				}
				if (tmp != NULL)
					OBJECT_DEREF(&tmp, "omapi_wfc");
			}
		}
		prev = io;
	}

	return (ISC_R_SUCCESS);
}

isc_result_t
omapi_io_setvalue(omapi_object_t *io, omapi_object_t *id,
		  omapi_data_string_t *name, omapi_typed_data_t *value)
{
	REQUIRE(io != NULL && io->type == omapi_type_io_object);

	PASS_SETVALUE(io);
}

isc_result_t
omapi_io_getvalue(omapi_object_t *io, omapi_object_t *id,
		  omapi_data_string_t *name, omapi_value_t **value)
{
	REQUIRE(io != NULL && io->type == omapi_type_io_object);
	
	PASS_GETVALUE(io);
}

void
omapi_io_destroy(omapi_object_t *io, const char *name) {
	REQUIRE(io != NULL && io->type == omapi_type_io_object);

	(void)name;		/* Unused. */
}

isc_result_t
omapi_io_signalhandler(omapi_object_t *io, const char *name, va_list ap)
{
	REQUIRE(io != NULL && io->type == omapi_type_io_object);

	PASS_SIGNAL(io);
}

isc_result_t
omapi_io_stuffvalues(omapi_object_t *connection, omapi_object_t *id,
		      omapi_object_t *io)
{
	REQUIRE(io != NULL && io->type == omapi_type_io_object);

	PASS_STUFFVALUES(io);
}

isc_result_t
omapi_waiter_signal_handler(omapi_object_t *h, const char *name, va_list ap) {
	omapi_waiter_object_t *waiter;

	REQUIRE(h != NULL && h->type == omapi_type_waiter);
	
	if (strcmp(name, "ready") == 0) {
		waiter = (omapi_waiter_object_t *)h;
		waiter->ready = 1;
		return (ISC_R_SUCCESS);
	}

	PASS_SIGNAL(h);
}