command: added command "idle"

"idle" waits until something noteworthy happens on the server,
e.g. song change, playlist modified, database updated.  This allows
clients to keep up to date without polling.

1 files changed, 56 insertions, 0 deletions

diff --git a/src/idle.c b/src/idle.c
new file mode 100644
index 000000000..c779d0a91
--- /dev/null
+++ b/src/idle.c
@@ -0,0 +1,56 @@
+/* the Music Player Daemon (MPD)
+ * Copyright (C) 2008 Max Kellermann <max@duempel.org>
+ * 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
+ */
+
+/*
+ * Support library for the "idle" command.
+ *
+ */
+
+#include "idle.h"
+#include "main_notify.h"
+
+#include <assert.h>
+#include <pthread.h>
+
+static unsigned idle_flags;
+static pthread_mutex_t idle_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+void
+idle_add(unsigned flags)
+{
+	assert(flags != 0);
+
+	pthread_mutex_lock(&idle_mutex);
+	idle_flags |= flags;
+	pthread_mutex_unlock(&idle_mutex);
+
+	wakeup_main_task();
+}
+
+unsigned
+idle_get(void)
+{
+	unsigned flags;
+
+	pthread_mutex_lock(&idle_mutex);
+	flags = idle_flags;
+	idle_flags = 0;
+	pthread_mutex_unlock(&idle_mutex);
+
+	return flags;
+}