/*
    Copyright (c) 2009-2012 250bpm s.r.o.
    Copyright (c) 2007-2009 iMatix Corporation
    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file

    This file is part of Crossroads I/O project.

    Crossroads I/O is free software; you can redistribute it and/or modify it
    under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    Crossroads is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "devpoll.hpp"

#if defined XS_HAVE_DEVPOLL

#include <sys/devpoll.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <limits.h>
#include <algorithm>

#include "devpoll.hpp"
#include "err.hpp"
#include "config.hpp"

xs::devpoll_t::devpoll_t (xs::ctx_t *ctx_, uint32_t tid_) :
    io_thread_t (ctx_, tid_),
    stopping (false)
{
    devpoll_fd = open ("/dev/poll", O_RDWR);
    errno_assert (devpoll_fd != -1);
}

xs::devpoll_t::~devpoll_t ()
{
    worker.stop ();
    close (devpoll_fd);
}

void xs::devpoll_t::devpoll_ctl (fd_t fd_, short events_)
{
    struct pollfd pfd = {fd_, events_, 0};
    ssize_t rc = write (devpoll_fd, &pfd, sizeof pfd);
    xs_assert (rc == sizeof pfd);
}

xs::handle_t xs::devpoll_t::add_fd (fd_t fd_,
    i_poll_events *reactor_)
{
    //  If the file descriptor table is too small expand it.
    fd_table_t::size_type sz = fd_table.size ();
    if (sz <= (fd_table_t::size_type) fd_) {
        fd_table.resize (fd_ + 1);
        while (sz != (fd_table_t::size_type) (fd_ + 1)) {
            fd_table [sz].valid = false;
            ++sz;
        }
    }

    assert (!fd_table [fd_].valid);

    fd_table [fd_].events = 0;
    fd_table [fd_].reactor = reactor_;
    fd_table [fd_].valid = true;
    fd_table [fd_].accepted = false;

    devpoll_ctl (fd_, 0);
    pending_list.push_back (fd_);

    //  Increase the load metric of the thread.
    adjust_load (1);

    return fdtoptr (fd_);
}

void xs::devpoll_t::rm_fd (handle_t handle_)
{
    fd_t fd = ptrtofd (handle_);

    assert (fd_table [fd].valid);

    devpoll_ctl (fd, POLLREMOVE);
    fd_table [fd].valid = false;

    //  Decrease the load metric of the thread.
    adjust_load (-1);
}

void xs::devpoll_t::set_pollin (handle_t handle_)
{
    fd_t fd = ptrtofd (handle_);

    devpoll_ctl (fd, POLLREMOVE);
    fd_table [fd].events |= POLLIN;
    devpoll_ctl (fd, fd_table [fd].events);
}

void xs::devpoll_t::reset_pollin (handle_t handle_)
{
    fd_t fd = ptrtofd (handle_);

    devpoll_ctl (fd, POLLREMOVE);
    fd_table [fd].events &= ~((short) POLLIN);
    devpoll_ctl (fd, fd_table [fd].events);
}

void xs::devpoll_t::set_pollout (handle_t handle_)
{
    fd_t fd = ptrtofd (handle_);

    devpoll_ctl (fd, POLLREMOVE);
    fd_table [fd].events |= POLLOUT;
    devpoll_ctl (fd, fd_table [fd].events);
}

void xs::devpoll_t::reset_pollout (handle_t handle_)
{
    fd_t fd = ptrtofd (handle_);

    devpoll_ctl (fd, POLLREMOVE);
    fd_table [fd].events &= ~((short) POLLOUT);
    devpoll_ctl (fd, fd_table [fd].events);
}

void xs::devpoll_t::xstart ()
{
    worker.start (worker_routine, this);
}

void xs::devpoll_t::xstop ()
{
    stopping = true;
}

void xs::devpoll_t::loop ()
{
    while (!stopping) {

        struct pollfd ev_buf [max_io_events];
        struct dvpoll poll_req;

        for (pending_list_t::size_type i = 0; i < pending_list.size (); i ++)
            fd_table [pending_list [i]].accepted = true;
        pending_list.clear ();

        //  Execute any due timers.
        int timeout = (int) execute_timers ();

        //  Wait for events.
        //  On Solaris, we can retrieve no more then (OPEN_MAX - 1) events.
        poll_req.dp_fds = &ev_buf [0];
#if defined XS_HAVE_SOLARIS
        poll_req.dp_nfds = std::min ((int) max_io_events, OPEN_MAX - 1);
#else
        poll_req.dp_nfds = max_io_events;
#endif
        poll_req.dp_timeout = timeout ? timeout : -1;
        int n = ioctl (devpoll_fd, DP_POLL, &poll_req);
        if (n == -1 && errno == EINTR)
            continue;
        errno_assert (n != -1);

        for (int i = 0; i < n; i ++) {

            fd_entry_t *fd_ptr = &fd_table [ev_buf [i].fd];
            if (!fd_ptr->valid || !fd_ptr->accepted)
                continue;
            if (ev_buf [i].revents & (POLLERR | POLLHUP))
                fd_ptr->reactor->in_event (ev_buf [i].fd);
            if (!fd_ptr->valid || !fd_ptr->accepted)
                continue;
            if (ev_buf [i].revents & POLLOUT)
                fd_ptr->reactor->out_event (ev_buf [i].fd);
            if (!fd_ptr->valid || !fd_ptr->accepted)
                continue;
            if (ev_buf [i].revents & POLLIN)
                fd_ptr->reactor->in_event (ev_buf [i].fd);
        }
    }
}

void xs::devpoll_t::worker_routine (void *arg_)
{
    ((devpoll_t*) arg_)->loop ();
}

#endif