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Diffstat (limited to 'src/main_notify.c')
| -rw-r--r-- | src/main_notify.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/src/main_notify.c b/src/main_notify.c new file mode 100644 index 000000000..bb5db8259 --- /dev/null +++ b/src/main_notify.c @@ -0,0 +1,130 @@ +/* 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_broadcast(&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); +} + |