/*

 * Copyright 2007-2012 Niels Provos and Nick Mathewson

 * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu>

 * Copyright 2003 Michael A. Davis <mike@datanerds.net>

 *

 * 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 <winsock2.h>

#include <windows.h>

#include <sys/types.h>

#include <sys/queue.h>

#include <limits.h>

#include <signal.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include "event2/util.h"

#include "event2/event-config.h"

#include "util-internal.h"

#include "log-internal.h"

#include "event2/event.h"

#include "event-internal.h"

#include "evmap-internal.h"

#include "event2/thread.h"

#include "evthread-internal.h"

#define XFREE(ptr) do { if (ptr) mm_free(ptr); } while (0)

extern struct event_list timequeue;

extern struct event_list addqueue;

struct win_fd_set {

	u_int fd_count;

	SOCKET fd_array[1];

};

/* MSDN says this is required to handle SIGFPE */

volatile double SIGFPE_REQ = 0.0f;

struct idx_info {

	int read_pos_plus1;

	int write_pos_plus1;

};

struct win32op {

	unsigned num_fds_in_fd_sets;

	int resize_out_sets;

	struct win_fd_set *readset_in;

	struct win_fd_set *writeset_in;

	struct win_fd_set *readset_out;

	struct win_fd_set *writeset_out;

	struct win_fd_set *exset_out;

	unsigned signals_are_broken : 1;

};

static void *win32_init(struct event_base *);

static int win32_add(struct event_base *, evutil_socket_t, short old, short events, void *_idx);

static int win32_del(struct event_base *, evutil_socket_t, short old, short events, void *_idx);

static int win32_dispatch(struct event_base *base, struct timeval *);

static void win32_dealloc(struct event_base *);

struct eventop win32ops = {

	"win32",

	win32_init,

	win32_add,

	win32_del,

	win32_dispatch,

	win32_dealloc,

	0, /* doesn't need reinit */

	0, /* No features supported. */

	sizeof(struct idx_info),

};

#define FD_SET_ALLOC_SIZE(n) ((sizeof(struct win_fd_set) + ((n)-1)*sizeof(SOCKET)))

static int

grow_fd_sets(struct win32op *op, unsigned new_num_fds)

{

	size_t size;

	EVUTIL_ASSERT(new_num_fds >= op->readset_in->fd_count &&

	       new_num_fds >= op->writeset_in->fd_count);

	EVUTIL_ASSERT(new_num_fds >= 1);

	size = FD_SET_ALLOC_SIZE(new_num_fds);

	if (!(op->readset_in = mm_realloc(op->readset_in, size)))

		return (-1);

	if (!(op->writeset_in = mm_realloc(op->writeset_in, size)))

		return (-1);

	op->resize_out_sets = 1;

	op->num_fds_in_fd_sets = new_num_fds;

	return (0);

}

static int

do_fd_set(struct win32op *op, struct idx_info *ent, evutil_socket_t s, int read)

{

	struct win_fd_set *set = read ? op->readset_in : op->writeset_in;

	if (read) {

		if (ent->read_pos_plus1 > 0)

			return (0);

	} else {

		if (ent->write_pos_plus1 > 0)

			return (0);

	}

	if (set->fd_count == op->num_fds_in_fd_sets) {

		if (grow_fd_sets(op, op->num_fds_in_fd_sets*2))

			return (-1);

		/* set pointer will have changed and needs reiniting! */

		set = read ? op->readset_in : op->writeset_in;

	}

	set->fd_array[set->fd_count] = s;

	if (read)

		ent->read_pos_plus1 = set->fd_count+1;

	else

		ent->write_pos_plus1 = set->fd_count+1;

	return (set->fd_count++);

}

static int

do_fd_clear(struct event_base *base,

			struct win32op *op, struct idx_info *ent, int read)

{

	int i;

	struct win_fd_set *set = read ? op->readset_in : op->writeset_in;

	if (read) {

		i = ent->read_pos_plus1 - 1;

		ent->read_pos_plus1 = 0;

	} else {

		i = ent->write_pos_plus1 - 1;

		ent->write_pos_plus1 = 0;

	}

	if (i < 0)

		return (0);

	if (--set->fd_count != (unsigned)i) {

		struct idx_info *ent2;

		SOCKET s2;

		s2 = set->fd_array[i] = set->fd_array[set->fd_count];

		ent2 = evmap_io_get_fdinfo(&base->io, s2);

		if (!ent2) /* This indicates a bug. */

			return (0);

		if (read)

			ent2->read_pos_plus1 = i+1;

		else

			ent2->write_pos_plus1 = i+1;

	}

	return (0);

}

#define NEVENT 32

void *

win32_init(struct event_base *_base)

{

	struct win32op *winop;

	size_t size;

	if (!(winop = mm_calloc(1, sizeof(struct win32op))))

		return NULL;

	winop->num_fds_in_fd_sets = NEVENT;

	size = FD_SET_ALLOC_SIZE(NEVENT);

	if (!(winop->readset_in = mm_malloc(size)))

		goto err;

	if (!(winop->writeset_in = mm_malloc(size)))

		goto err;

	if (!(winop->readset_out = mm_malloc(size)))

		goto err;

	if (!(winop->writeset_out = mm_malloc(size)))

		goto err;

	if (!(winop->exset_out = mm_malloc(size)))

		goto err;

	winop->readset_in->fd_count = winop->writeset_in->fd_count = 0;

	winop->readset_out->fd_count = winop->writeset_out->fd_count

		= winop->exset_out->fd_count = 0;

	if (evsig_init(_base) < 0)

		winop->signals_are_broken = 1;

	return (winop);

 err:

	XFREE(winop->readset_in);

	XFREE(winop->writeset_in);

	XFREE(winop->readset_out);

	XFREE(winop->writeset_out);

	XFREE(winop->exset_out);

	XFREE(winop);

	return (NULL);

}

int

win32_add(struct event_base *base, evutil_socket_t fd,

			 short old, short events, void *_idx)

{

	struct win32op *win32op = base->evbase;

	struct idx_info *idx = _idx;

	if ((events & EV_SIGNAL) && win32op->signals_are_broken)

		return (-1);

	if (!(events & (EV_READ|EV_WRITE)))

		return (0);

	event_debug(("%s: adding event for %d", __func__, (int)fd));

	if (events & EV_READ) {

		if (do_fd_set(win32op, idx, fd, 1)<0)

			return (-1);

	}

	if (events & EV_WRITE) {

		if (do_fd_set(win32op, idx, fd, 0)<0)

			return (-1);

	}

	return (0);

}

int

win32_del(struct event_base *base, evutil_socket_t fd, short old, short events,

		  void *_idx)

{

	struct win32op *win32op = base->evbase;

	struct idx_info *idx = _idx;

	event_debug(("%s: Removing event for "EV_SOCK_FMT,

		__func__, EV_SOCK_ARG(fd)));

	if (events & EV_READ)

		do_fd_clear(base, win32op, idx, 1);

	if (events & EV_WRITE)

		do_fd_clear(base, win32op, idx, 0);

	return 0;

}

static void

fd_set_copy(struct win_fd_set *out, const struct win_fd_set *in)

{

	out->fd_count = in->fd_count;

	memcpy(out->fd_array, in->fd_array, in->fd_count * (sizeof(SOCKET)));

}

/*

  static void dump_fd_set(struct win_fd_set *s)

  {

  unsigned int i;

  printf("[ ");

  for(i=0;i<s->fd_count;++i)

  printf("%d ",(int)s->fd_array[i]);

  printf("]\n");

  }

*/

int

win32_dispatch(struct event_base *base, struct timeval *tv)

{

	struct win32op *win32op = base->evbase;

	int res = 0;

	unsigned j, i;

	int fd_count;

	SOCKET s;

	if (win32op->resize_out_sets) {

		size_t size = FD_SET_ALLOC_SIZE(win32op->num_fds_in_fd_sets);

		if (!(win32op->readset_out = mm_realloc(win32op->readset_out, size)))

			return (-1);

		if (!(win32op->exset_out = mm_realloc(win32op->exset_out, size)))

			return (-1);

		if (!(win32op->writeset_out = mm_realloc(win32op->writeset_out, size)))

			return (-1);

		win32op->resize_out_sets = 0;

	}

	fd_set_copy(win32op->readset_out, win32op->readset_in);

	fd_set_copy(win32op->exset_out, win32op->writeset_in);

	fd_set_copy(win32op->writeset_out, win32op->writeset_in);

	fd_count =

	    (win32op->readset_out->fd_count > win32op->writeset_out->fd_count) ?

	    win32op->readset_out->fd_count : win32op->writeset_out->fd_count;

	if (!fd_count) {

		long msec = tv ? evutil_tv_to_msec(tv) : LONG_MAX;

		/* Sleep's DWORD argument is unsigned long */

		if (msec < 0)

			msec = LONG_MAX;

		/* Windows doesn't like you to call select() with no sockets */

		Sleep(msec);

		return (0);

	}

	EVBASE_RELEASE_LOCK(base, th_base_lock);

	res = select(fd_count,

		     (struct fd_set*)win32op->readset_out,

		     (struct fd_set*)win32op->writeset_out,

		     (struct fd_set*)win32op->exset_out, tv);

	EVBASE_ACQUIRE_LOCK(base, th_base_lock);

	event_debug(("%s: select returned %d", __func__, res));

	if (res <= 0) {

		return res;

	}

	if (win32op->readset_out->fd_count) {

		i = rand() % win32op->readset_out->fd_count;

		for (j=0; j<win32op->readset_out->fd_count; ++j) {

			if (++i >= win32op->readset_out->fd_count)

				i = 0;

			s = win32op->readset_out->fd_array[i];

			evmap_io_active(base, s, EV_READ);

		}

	}

	if (win32op->exset_out->fd_count) {

		i = rand() % win32op->exset_out->fd_count;

		for (j=0; j<win32op->exset_out->fd_count; ++j) {

			if (++i >= win32op->exset_out->fd_count)

				i = 0;

			s = win32op->exset_out->fd_array[i];

			evmap_io_active(base, s, EV_WRITE);

		}

	}

	if (win32op->writeset_out->fd_count) {

		SOCKET s;

		i = rand() % win32op->writeset_out->fd_count;

		for (j=0; j<win32op->writeset_out->fd_count; ++j) {

			if (++i >= win32op->writeset_out->fd_count)

				i = 0;

			s = win32op->writeset_out->fd_array[i];

			evmap_io_active(base, s, EV_WRITE);

		}

	}

	return (0);

}

void

win32_dealloc(struct event_base *_base)

{

	struct win32op *win32op = _base->evbase;

	evsig_dealloc(_base);

	if (win32op->readset_in)

		mm_free(win32op->readset_in);

	if (win32op->writeset_in)

		mm_free(win32op->writeset_in);

	if (win32op->readset_out)

		mm_free(win32op->readset_out);

	if (win32op->writeset_out)

		mm_free(win32op->writeset_out);

	if (win32op->exset_out)

		mm_free(win32op->exset_out);

	/* XXXXX free the tree. */

	memset(win32op, 0, sizeof(*win32op));

	mm_free(win32op);

}