libsaria: Added queue_changed callback

This callback is used when ids are either added or removed from the
queue.

libsaria/callbacks.py

@@ -36,3 +36,7 @@ def load_playlist():
 on_new_source = null_cb
 def new_source():
 	on_new_source()
+
+on_queue_changed = null_cb
+def queue_changed():
+	on_queue_changed()

libsaria/sources/queue/queue.py

@@ -1,6 +1,7 @@
 # Bryan Schumaker (5 / 7 / 2011)
 
 import threading
+from libsaria import callbacks
 queue_lock   = threading.Lock()
 lock_queue   = queue_lock.acquire
 unlock_queue = queue_lock.release
@@ -12,6 +13,7 @@ def add_ids(id_list):
 	lock_queue()
 	queue_list.extend(id_list)
 	unlock_queue()
+	callbacks.queue_changed()
 
 def rm_ids(id_list):
 	lock_queue()
@@ -19,6 +21,7 @@ def rm_ids(id_list):
 		if id in queue_list:
 			queue_list.remove(id)
 	unlock_queue()
+	callbacks.queue_changed()
 
 def pop():
 	lock_queue()
@@ -26,6 +29,7 @@ def pop():
 	if len(queue_list) > 0:
 		id = queue_list.pop(0)
 	unlock_queue()
+	callbacks.queue_changed()
 	return id
 
 def reset():