Gstreamer locking

Locking for gstreamer operations may help prevent a double free error I
was getting.

libsaria/music/audio.py

@@ -1,7 +1,9 @@
 # Bryan Schumaker (8/7/2010)
 
 import libsaria
+from libsaria import threads
 
+lock   = threads.get_mutex("gstreamer")
 gst    = None
 player = None
 time   = None
@@ -13,22 +15,30 @@ def init():
 	global gst
 	global player
 	global time
+	global lock
 	import gst
 
+	lock.acquire()
 	player = gst.element_factory_make("playbin2", "player")
-	set_volume(libsaria.prefs["volume"])
+	set_volume_locked(libsaria.prefs["volume"])
 	time = gst.Format(gst.FORMAT_TIME)
 	bus = player.get_bus()
 	bus.add_signal_watch()
 	bus.connect("message", on_message)
+	lock.release()
 
-
-def reset():
+def reset_locked():
 	global player
 	global length
 	player.set_state(gst.STATE_NULL)
 	length = None
 
+def reset():
+	global lock
+	lock.acquire()
+	reset_locked()
+	lock.release()
+
 
 def on_message(bus, message):
 	if message.type == gst.MESSAGE_EOS:
@@ -36,22 +46,31 @@ def on_message(bus, message):
 
 
 def on_quit():
-	global player
-	player.set_state(gst.STATE_NULL)
+	global lock
+	lock.acquire()
+	reset_locked()
+	lock.release()
 libsaria.event.invite("PREQUIT", on_quit)
 
 
-def get_state():
+def get_state_locked():
 	global player
 	return player.get_state()[1]
 
+def get_state():
+	global lock
+	lock.acquire()
+	state = get_state_locked()
+	lock.release()
+	return state
+
 
 # Returns the length of the song in ms
-def duration():
+def duration_locked():
 	global length
 	global player
 	global time
-	if get_state() == gst.STATE_NULL:
+	if get_state_locked() == gst.STATE_NULL:
 		return 0
 	if length == None:
 		try:
@@ -60,11 +79,18 @@ def duration():
 			length = 0
 	return float(length)
 
+def duration():
+	global lock
+	lock.acquire()
+	ret = duration_locked()
+	lock.release()
+	return ret
 
-def position():
+
+def position_locked():
 	global time
 	global player
-	if get_state() == gst.STATE_NULL:
+	if get_state_locked() == gst.STATE_NULL:
 		return float(0)
 	try:
 		pos = player.query_position(time)[0]
@@ -72,46 +98,91 @@ def position():
 		pos = 0
 	return float(pos)
 
+def position():
+	global lock
+	lock.acquire()
+	ret = position_locked()
+	lock.release()
+	return ret
 
-def load(file):
+
+def load_locked(file):
 	global gst
 	global player
-	reset()
+	reset_locked()
 	#player.set_state(gst.STATE_NULL)
 	player.set_property("uri", "file://%s"%file)
 	player.set_state(gst.STATE_PAUSED)
 	return file
 
+def load(file):
+	global lock
+	lock.acquire()
+	ret = load_locked(file)
+	lock.release()
+	return ret
 
-def play():
+
+def play_locked():
 	global gst
 	global player
 	player.set_state(gst.STATE_PLAYING)
 
+def play():
+	global lock
+	lock.acquire()
+	play_locked()
+	lock.release()
 
-def pause():
+
+def pause_locked():
 	global gst
 	global player
 	player.set_state(gst.STATE_PAUSED)
 
+def pause():
+	global lock
+	lock.acquire()
+	pause_locked()
+	lock.release()
+
+def stop_locked():
+	pause_locked()
+	seek_locked(0)
+
 def stop():
-	pause()
-	seek(0)
+	global lock
+	lock.acquire()
+	stop_locked()
+	lock.release()
 
 
-def seek(prcnt):
+def seek_locked(prcnt):
 	global player
 	global time
 	global gst
 	try:
-		spot = duration() * prcnt
+		spot = duration_locked() * prcnt
 		player.seek_simple(time, gst.SEEK_FLAG_FLUSH, spot)
 	except:
 		pass
 
+def seek(prcnt):
+	global lock
+	lock.acquire()
+	seek_locked(prcnt)
+	lock.release()
 
-def set_volume(prcnt):
+
+def set_volume_locked(prcnt):
 	global player
 	player.set_property("volume", prcnt)
 	libsaria.prefs["volume"] = prcnt
 	return prcnt
+
+def set_volume(prcnt):
+	global lock
+	lock.acquire()
+	ret = set_volume_locked(prcnt)
+	lock.release()
+	return ret