libsaria: Move playlist load, save, and reset functions

I moved them to playlist.py so they can grab the lock and safely do
stuff.  I save after adding or removing song ids.  I also save after
resetting the playlist.

libsaria/sources/playlist/__init__.py

@@ -18,6 +18,8 @@ cur_index  = None
 # Function pointers for convenience
 add_ids = playlist.add_ids
 rm_ids  = playlist.rm_ids
+load    = playlist.load
+reset   = playlist.reset
 
 def init():
 	global library
@@ -30,32 +32,6 @@ def init():
 	source.get_attrs  = library.get_attrs
 	source.set_attr   = library.set_attr
 	source.get_cur_id = get_cur_id
-	source.save       = save
-
-def reset():
-	global recent
-	global cur_index
-	recent    = []
-	playlist.song_list = []
-	cur_index = -1
-
-def default_objects():
-	return ([], [], -1)
-
-def load():
-	global song_set
-	global recent
-	global visible
-	global cur_index
-	objects = libsaria.storage.load_obj("playlist", default_objects)
-	if objects == None or len(objects) != 3:
-		reset()
-	else:
-		playlist.song_list = objects[0]
-		recent    = objects[1]
-		cur_index = objects[2]
-		if cur_index >= 0:
-			libsaria.sources.cur_lib_id = playlist.song_list[cur_index]
 
 def init_bg():
 	init()
@@ -65,9 +41,6 @@ def startup():
 	if cur_index >= 0:
 		load_id(playlist.song_list[cur_index])
 
-def save():
-	libsaria.storage.save_obj("playlist", (playlist.song_list, recent, cur_index))
-
 def list():
 	for id in playlist.song_list:
 		yield id

libsaria/sources/playlist/playlist.py

@@ -1,6 +1,7 @@
 # Bryan Schumaker (5 / 11 / 2011)
 
 import threading
+from libsaria import storage
 plist_lock   = threading.Lock()
 lock_plist   = plist_lock.acquire
 unlock_plist = plist_lock.release
@@ -9,10 +10,29 @@ unlock_plist = plist_lock.release
 song_list = []
 song_set  = set()
 
+def load():
+	global song_list
+	plist_list = storage.load_obj("playlist", list)
+	if plist_list.__class__ != list:
+		plist_list = []
+	lock_plist()
+	song_list = plist_list
+	unlock_plist()
+
+def save():
+	storage.save_obj("playlist", song_list)
+
+def reset():
+	global song_list
+	lock_plist()
+	song_list = []
+	save()
+	unlock_plist()
 
 def add_ids(id_list):
 	lock_plist()
 	song_list.extend(id_list)
+	save()
 	unlock_plist()
 
 def rm_ids(id_list):
@@ -20,6 +40,7 @@ def rm_ids(id_list):
 	for id in id_list:
 		if id in song_list:
 			song_list.remove(id)
+	save()
 	unlock_plist()
 
 def as_set():