/* Kqueue(2)-based ae.c module
 *
 * Copyright (C) 2009 Harish Mallipeddi - harish.mallipeddi@gmail.com
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * * 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.
 * * Neither the name of Redis nor the names of its contributors may be used
 * to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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/types.h>
#include <sys/event.h>
#include <sys/time.h>

typedef struct aeApiState {
 int kqfd;
 struct kevent *events;
} aeApiState;

static int aeApiCreate(aeEventLoop *eventLoop) {
 aeApiState *state = zmalloc(sizeof(aeApiState));

 if (!state) return -1;
 state->events = zmalloc(sizeof(struct kevent)*eventLoop->setsize);
 if (!state->events) {
 zfree(state);
 return -1;
 }
 state->kqfd = kqueue();
 if (state->kqfd == -1) {
 zfree(state->events);
 zfree(state);
 return -1;
 }
 eventLoop->apidata = state;
 return 0;
}

static int aeApiResize(aeEventLoop *eventLoop, int setsize) {
 aeApiState *state = eventLoop->apidata;

 state->events = zrealloc(state->events, sizeof(struct kevent)*setsize);
 return 0;
}

static void aeApiFree(aeEventLoop *eventLoop) {
 aeApiState *state = eventLoop->apidata;

 close(state->kqfd);
 zfree(state->events);
 zfree(state);
}

static int aeApiAddEvent(aeEventLoop *eventLoop, int fd, int mask) {
 aeApiState *state = eventLoop->apidata;
 struct kevent ke;

 if (mask & AE_READABLE) {
 EV_SET(&ke, fd, EVFILT_READ, EV_ADD, 0, 0, NULL);
 if (kevent(state->kqfd, &ke, 1, NULL, 0, NULL) == -1) return -1;
 }
 if (mask & AE_WRITABLE) {
 EV_SET(&ke, fd, EVFILT_WRITE, EV_ADD, 0, 0, NULL);
 if (kevent(state->kqfd, &ke, 1, NULL, 0, NULL) == -1) return -1;
 }
 return 0;
}

static void aeApiDelEvent(aeEventLoop *eventLoop, int fd, int mask) {
 aeApiState *state = eventLoop->apidata;
 struct kevent ke;

 if (mask & AE_READABLE) {
 EV_SET(&ke, fd, EVFILT_READ, EV_DELETE, 0, 0, NULL);
 kevent(state->kqfd, &ke, 1, NULL, 0, NULL);
 }
 if (mask & AE_WRITABLE) {
 EV_SET(&ke, fd, EVFILT_WRITE, EV_DELETE, 0, 0, NULL);
 kevent(state->kqfd, &ke, 1, NULL, 0, NULL);
 }
}

static int aeApiPoll(aeEventLoop *eventLoop, struct timeval *tvp) {
 aeApiState *state = eventLoop->apidata;
 int retval, numevents = 0;

 if (tvp != NULL) {
 struct timespec timeout;
 timeout.tv_sec = tvp->tv_sec;
 timeout.tv_nsec = tvp->tv_usec * 1000;
 retval = kevent(state->kqfd, NULL, 0, state->events, eventLoop->setsize,
 &timeout);
 } else {
 retval = kevent(state->kqfd, NULL, 0, state->events, eventLoop->setsize,
 NULL);
 }

 if (retval > 0) {
 int j;

 numevents = retval;
 for(j = 0; j < numevents; j++) {
 int mask = 0;
 struct kevent *e = state->events+j;

 if (e->filter == EVFILT_READ) mask |= AE_READABLE;
 if (e->filter == EVFILT_WRITE) mask |= AE_WRITABLE;
 eventLoop->fired[j].fd = e->ident;
 eventLoop->fired[j].mask = mask;
 }
 }
 return numevents;
}

static char *aeApiName(void) {
 return "kqueue";
}