Fix the problem of songs not advancing without client activity

src/Makefile.am

@@ -52,6 +52,7 @@ mpd_headers = \
 	listen.h \
 	log.h \
 	ls.h \
+	main_notify.h \
 	mpd_types.h \
 	myfprintf.h \
 	normalize.h \
@@ -109,6 +110,7 @@ mpd_SOURCES = \
 	log.c \
 	ls.c \
 	main.c \
+	main_notify.c \
 	myfprintf.c \
 	normalize.c \
 	compress.c \

src/decode.c

@@ -24,6 +24,7 @@
 #include "path.h"
 #include "log.h"
 #include "ls.h"
+#include "main_notify.h"
 
 /* called inside decoder_task (inputPlugins) */
 void decoder_wakeup_player(void)

src/interface.c

@@ -27,6 +27,7 @@
 #include "ioops.h"
 #include "myfprintf.h"
 #include "os_compat.h"
+#include "main_notify.h"
 
 #include "../config.h"
 
@@ -494,7 +495,9 @@ int doIOForInterfaces(void)
 
 		registered_IO_add_fds(&fdmax, &rfds, &wfds, &efds);
 
+		main_notify_lock();
 		selret = select(fdmax + 1, &rfds, &wfds, &efds, NULL);
+		main_notify_unlock();
 
 		if (selret < 0 && errno == EINTR)
 			break;

src/main.c

@@ -43,6 +43,7 @@
 #include "utils.h"
 #include "normalize.h"
 #include "zeroconf.h"
+#include "main_notify.h"
 #include "os_compat.h"
 
 #define SYSTEM_CONFIG_FILE_LOCATION	"/etc/mpd.conf"
@@ -56,8 +57,6 @@ typedef struct _Options {
 	int verbose;
 } Options;
 
-static Notify main_notify;
-
 /* 
  * from git-1.3.0, needed for solaris
  */
@@ -380,16 +379,6 @@ static void killFromPidFile(char *cmd, int killOption)
 	exit(EXIT_SUCCESS);
 }
 
-void wakeup_main_task(void)
-{
-	notifySignal(&main_notify);
-}
-
-void wait_main_task(void)
-{
-	notifySignal(&main_notify);
-}
-
 int main(int argc, char *argv[])
 {
 	Options options;
@@ -432,10 +421,9 @@ int main(int argc, char *argv[])
 	initNormalization();
 	initInputStream();
 
-	notifyInit(&main_notify);
-
 	daemonize(&options);
 
+	init_main_notify();
 	setup_log_output(options.stdOutput);
 
 	initSigHandlers();
@@ -447,8 +435,6 @@ int main(int argc, char *argv[])
 	playerInit(&getPlayerData()->playerControl);
 	read_state_file();
 
-	notifyEnter(&main_notify);
-
 	while (COMMAND_RETURN_KILL != doIOForInterfaces() &&
 	       COMMAND_RETURN_KILL != handlePendingSignals()) {
 		syncPlayerAndPlaylist();

src/main_notify.c

+/* 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);
+}
+

src/main_notify.h

+/* 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
+ */
+
+#ifndef MAIN_NOTIFY_H
+#define MAIN_NOTIFY_H
+
+void init_main_notify(void);
+
+void wakeup_main_task(void);
+
+void wait_main_task(void);
+
+void main_notify_lock(void);
+
+void main_notify_unlock(void);
+
+#endif /* MAIN_NOTIFY_H */

src/player.c

@@ -32,6 +32,7 @@
 #include "permission.h"
 #include "ack.h"
 #include "os_compat.h"
+#include "main_notify.h"
 
 static void playerCloseAudio(void);
 

src/player.h

@@ -76,10 +76,6 @@ typedef struct _PlayerControl {
 	volatile double totalPlayTime;
 } PlayerControl;
 
-void wakeup_main_task(void);
-
-void wait_main_task(void);
-
 void wakeup_player_nb(PlayerControl *pc);
 
 void player_sleep(PlayerControl *pc);