/* io-unix.c - non-blocking io primitives for unix
 *
 * Copyright (C) 2009 Timo Teräs <timo.teras@iki.fi>
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 or later as
 * published by the Free Software Foundation.
 *
 * See http://www.gnu.org/ for details.
 */

int tf_open(struct tf_fd *fd, const char *pathname, int flags)
{
	int kfd, r;

	kfd = open(pathname, flags | O_CLOEXEC | O_NONBLOCK);
	if (unlikely(kfd < 0))
		return -errno;

	r = tf_fd_init(fd, kfd, TF_FD_AUTOCLOSE | TF_FD_STREAM_ORIENTED);
	if (r < 0) {
		close(kfd);
		return r;
	}
	return 0;
}

int tf_open_fd(struct tf_fd *fd, int kfd)
{
	int mode, flags = 0;

	mode = fcntl(kfd, F_GETFL, 0);
	if (!(mode & O_NONBLOCK)) {
		fcntl(fd->fd, F_SETFL, mode | O_NONBLOCK);
		flags |= TF_FD_RESTORE_BLOCKING;
	}

	return tf_fd_init(fd, kfd, TF_FD_STREAM_ORIENTED | flags);
}

int tf_close(struct tf_fd *fd)
{
	int r;

	if (fd->flags & TF_FD_RESTORE_BLOCKING) {
		fcntl(fd->fd, F_SETFL, fcntl(fd->fd, F_GETFL, 0) & ~O_NONBLOCK);
	}
	if (fd->flags & TF_FD_AUTOCLOSE) {
		r = close(fd->fd);
		if (unlikely(r == -1))
			return -errno;
	}
	return 0;
}

int tf_read(struct tf_fd *fd, void *buf, size_t count, tf_mtime_diff_t timeout)
{
	ssize_t n;
	int r, mode;

	mode = tf_schedule_timeout(timeout);
	tf_fd_wait(fd, EPOLLIN);
	do {
		n = read(fd->fd, buf, count);
		if (n == count) {
			r = 0;
			break;
		}
		if (n < 0) {
			if (errno == EINTR)
				continue;
			if (errno != EAGAIN) {
				r = errno;
				break;
			}
		} else if (n == 0) {
			r = EIO;
			break;
		} else {
			buf += n;
			count -= n;
			if (!(fd->flags & TF_FD_STREAM_ORIENTED))
				continue;
		}

		r = tf_schedule(mode);
		if (r != TF_WAKEUP_FD)
			break;
	} while (1);
	tf_fd_release(fd);

	return -r;
}

int tf_write(struct tf_fd *fd, const void *buf, size_t count,
	     tf_mtime_diff_t timeout)
{
	ssize_t n;
	int r, mode;

	mode = tf_schedule_timeout(timeout);
	tf_fd_wait(fd, EPOLLOUT);
	do {
		n = write(fd->fd, buf, count);
		if (n == count) {
			r = 0;
			break;
		}
		if (n < 0) {
			if (errno == EINTR)
				continue;
			if (errno != EAGAIN) {
				r = errno;
				break;
			}
		} else {
			buf += n;
			count -= n;
			if (!(fd->flags & TF_FD_STREAM_ORIENTED))
				continue;
		}

		r = tf_schedule(mode);
		if (r != TF_WAKEUP_FD)
			break;
	} while (1);
	tf_fd_release(fd);

	return -r;
}