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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 "event_pipe.h"
#include "log.h"
#include <assert.h>
#include <glib.h>
#include <string.h>
#ifdef WIN32
/* for _O_BINARY */
#include <fcntl.h>
#endif
static int event_pipe[2];
static GMutex *event_pipe_mutex;
static bool pipe_events[PIPE_EVENT_MAX];
static event_pipe_callback_t event_pipe_callbacks[PIPE_EVENT_MAX];
/**
* Invoke the callback for a certain event.
*/
static void
event_pipe_invoke(enum pipe_event event)
{
assert((unsigned)event < PIPE_EVENT_MAX);
assert(event_pipe_callbacks[event] != NULL);
event_pipe_callbacks[event]();
}
static void
consume_pipe(void)
{
char buffer[256];
ssize_t r = read(event_pipe[0], buffer, sizeof(buffer));
bool events[PIPE_EVENT_MAX];
if (r < 0 && errno != EAGAIN && errno != EINTR)
FATAL("error reading from pipe: %s\n", strerror(errno));
g_mutex_lock(event_pipe_mutex);
memcpy(events, pipe_events, sizeof(events));
memset(pipe_events, 0, sizeof(pipe_events));
g_mutex_unlock(event_pipe_mutex);
for (unsigned i = 0; i < PIPE_EVENT_MAX; ++i)
if (events[i])
/* invoke the event handler */
event_pipe_invoke(i);
}
static gboolean
main_notify_event(G_GNUC_UNUSED GIOChannel *source,
G_GNUC_UNUSED GIOCondition condition,
G_GNUC_UNUSED gpointer data)
{
consume_pipe();
return true;
}
void event_pipe_init(void)
{
GIOChannel *channel;
int ret;
#ifdef WIN32
ret = _pipe(event_pipe, 512, _O_BINARY);
#else
ret = pipe(event_pipe);
#endif
if (ret < 0)
g_error("Couldn't open pipe: %s", strerror(errno));
if (set_nonblocking(event_pipe[1]) < 0)
g_error("Couldn't set non-blocking I/O: %s", strerror(errno));
channel = g_io_channel_unix_new(event_pipe[0]);
g_io_add_watch(channel, G_IO_IN, main_notify_event, NULL);
g_io_channel_unref(channel);
event_pipe_mutex = g_mutex_new();
}
void event_pipe_deinit(void)
{
g_mutex_free(event_pipe_mutex);
close(event_pipe[0]);
close(event_pipe[1]);
}
void
event_pipe_register(enum pipe_event event, event_pipe_callback_t callback)
{
assert((unsigned)event < PIPE_EVENT_MAX);
assert(event_pipe_callbacks[event] == NULL);
event_pipe_callbacks[event] = callback;
}
void event_pipe_emit(enum pipe_event event)
{
ssize_t w;
assert((unsigned)event < PIPE_EVENT_MAX);
g_mutex_lock(event_pipe_mutex);
if (pipe_events[event]) {
/* already set: don't write */
g_mutex_unlock(event_pipe_mutex);
return;
}
pipe_events[event] = true;
g_mutex_unlock(event_pipe_mutex);
w = write(event_pipe[1], "", 1);
if (w < 0 && errno != EAGAIN && errno != EINTR)
g_error("error writing to pipe: %s", strerror(errno));
}
void event_pipe_emit_fast(enum pipe_event event)
{
assert((unsigned)event < PIPE_EVENT_MAX);
pipe_events[event] = true;
write(event_pipe[1], "", 1);
}
void event_pipe_wait(void)
{
consume_pipe();
}
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