/*
 * Copyright (c) 2002-2004 Niels Provos <provos@citi.umich.edu>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/time.h>
#include <event.h>
#include "config.h"

void bufferevent_read_pressure_cb(struct evbuffer *, size_t, size_t,
    void *);

static int
bufferevent_add(struct event *ev, int timeout)
{
	struct timeval tv, *ptv = NULL;

	if (timeout) {
		timerclear(&tv);
		tv.tv_sec = timeout;
		ptv = &tv;
	}

	return (event_add(ev, ptv));
}

/*
 * This callback is executed when the size of the input buffer changes.
 * We use it to apply back pressure on the reading side.
 */
void
bufferevent_read_pressure_cb(struct evbuffer *buf, size_t old, size_t now,
    void *arg) {
	struct bufferevent *bufev = arg;
	/*
	 * If we are below the watermark then reschedule reading if it's
	 * still enabled.
	 */
	if (bufev->wm_read.high == 0 || now < bufev->wm_read.high) {
		evbuffer_setcb(buf, NULL, NULL);

		if (bufev->enabled & EV_READ)
#if HAVE_LIBEVENT2
			bufferevent_add(&bufev->ev_read,
			    bufev->timeout_read.tv_sec);
#else
			bufferevent_add(&bufev->ev_read, bufev->timeout_read);
#endif
	}
}