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/* the Music Player Daemon (MPD)
* Copyright (C) 2003-2007 Warren Dukes <warren.dukes@gmail.com>
* Copyright (C) 2008 Eric Wong <normalperson@yhbt.net>
*
* This project's homepage is: http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "main_notify.h"
#include "notify.h"
#include "utils.h"
#include "ioops.h"
#include "gcc.h"
#include "log.h"
static struct ioOps main_notify_IO;
static int main_pipe[2];
static pthread_t main_task;
static pthread_cond_t main_wakeup = PTHREAD_COND_INITIALIZER;
static pthread_mutex_t main_wakeup_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t select_mutex = PTHREAD_MUTEX_INITIALIZER;
static int ioops_fdset(fd_set * rfds,
mpd_unused fd_set * wfds, mpd_unused fd_set * efds)
{
FD_SET(main_pipe[0], rfds);
return main_pipe[0];
}
static void consume_pipe(void)
{
char buffer[2];
ssize_t r = read(main_pipe[0], buffer, sizeof(buffer));
if (r < 0 && errno != EAGAIN && errno != EINTR)
FATAL("error reading from pipe: %s\n", strerror(errno));
}
static int ioops_consume(int fd_count, fd_set * rfds,
mpd_unused fd_set * wfds, mpd_unused fd_set * efds)
{
if (FD_ISSET(main_pipe[0], rfds)) {
consume_pipe();
FD_CLR(main_pipe[0], rfds);
fd_count--;
}
return fd_count;
}
void init_main_notify(void)
{
if (pipe(main_pipe) < 0)
FATAL("Couldn't open pipe: %s", strerror(errno));
if (set_nonblocking(main_pipe[0]) < 0)
FATAL("Couldn't set non-blocking on main_notify fd: %s",
strerror(errno));
if (set_nonblocking(main_pipe[1]) < 0)
FATAL("Couldn't set non-blocking on main_notify fd: %s",
strerror(errno));
main_notify_IO.fdset = ioops_fdset;
main_notify_IO.consume = ioops_consume;
registerIO(&main_notify_IO);
main_task = pthread_self();
}
static int wakeup_via_pipe(void)
{
int ret = pthread_mutex_trylock(&select_mutex);
if (ret == EBUSY) {
ssize_t w = write(main_pipe[1], "", 1);
if (w < 0 && errno != EAGAIN && errno != EINTR)
FATAL("error writing to pipe: %s\n",
strerror(errno));
return 1;
} else {
pthread_mutex_unlock(&select_mutex);
return 0;
}
}
static void wakeup_via_cond(void)
{
int ret = pthread_mutex_trylock(&main_wakeup_mutex);
if (ret == EBUSY)
return; /* nope, no need to wakeup at all */
pthread_cond_signal(&main_wakeup);
pthread_mutex_unlock(&main_wakeup_mutex);
}
void wakeup_main_task(void)
{
assert(!pthread_equal(main_task, pthread_self()));
if (!wakeup_via_pipe())
wakeup_via_cond();
}
void main_notify_lock(void)
{
assert(pthread_equal(main_task, pthread_self()));
pthread_mutex_lock(&select_mutex);
}
void main_notify_unlock(void)
{
assert(pthread_equal(main_task, pthread_self()));
pthread_mutex_unlock(&select_mutex);
}
void wait_main_task(void)
{
assert(pthread_equal(main_task, pthread_self()));
pthread_mutex_lock(&main_wakeup_mutex);
pthread_cond_wait(&main_wakeup, &main_wakeup_mutex);
pthread_mutex_unlock(&main_wakeup_mutex);
}
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