X-Git-Url: http://code.vuplus.com/gitweb/?a=blobdiff_plain;f=lib%2Fpython%2FComponents%2FElement.py;h=54a1cc251cce6239537eec090249279db409d0d8;hb=7c1b7fe307737d330493694f0735b380b718576c;hp=6f812b207a6f9a4d7b5e0849c0068dd214ea18f3;hpb=ee0903f520403c5e03caef287f813e7b062d05ab;p=vuplus_dvbapp

diff --git a/lib/python/Components/Element.py b/lib/python/Components/Element.py
index 6f812b2..54a1cc2 100644
--- a/lib/python/Components/Element.py
+++ b/lib/python/Components/Element.py
@@ -7,7 +7,6 @@ from Tools.CList import CList
 class Element:
 	def __init__(self):
 		self.downstream_elements = CList()
-		self.upstream_elements = CList()
 		self.master = None
 		self.source = None
 
@@ -17,14 +16,34 @@ class Element:
 			self.master = downstream
 	
 	def connectUpstream(self, upstream):
-		self.upstream_elements.append(upstream)
-		self.source = upstream # for single-source elements (i.e., most of them.)
+		assert self.source is None
+		self.source = upstream
 		self.changed()
 	
 	def connect(self, upstream):
 		self.connectUpstream(upstream)
 		upstream.connectDownstream(self)
 
+	# we disconnect from down to up
+	def disconnectAll(self):
+		# we should not disconnect from upstream if
+		# there are still elements depending on us.
+		assert len(self.downstream_elements) == 0, "there are still downstream elements left"
+		if self.source:
+			self.source.disconnectDownstream(self)
+	
+	def disconnectDownstream(self, downstream):
+		self.downstream_elements.remove(downstream)
+		if self.master == downstream:
+			self.master = None
+		
+		if len(self.downstream_elements) == 0:
+			self.disconnectAll()
+
 	# default action: push downstream
-	def changed(self):
-		self.downstream_elements.changed()
+	def changed(self, *args, **kwargs):
+		self.downstream_elements.changed(*args, **kwargs)
+
+	def reconnectUpstream(self, new_upstream):
+		assert self.source is not None
+		self.source = new_upstream