1 files changed, 30 insertions, 0 deletions
diff --git a/lib/python/Components/Element.py b/lib/python/Components/Element.py
new file mode 100644
index 00000000..6f812b20
--- /dev/null
+++ b/lib/python/Components/Element.py
@@ -0,0 +1,30 @@
+from Tools.CList import CList
+
+# down                       up
+# Render Converter Converter Source
+
+# a bidirectional connection
+class Element:
+	def __init__(self):
+		self.downstream_elements = CList()
+		self.upstream_elements = CList()
+		self.master = None
+		self.source = None
+
+	def connectDownstream(self, downstream):
+		self.downstream_elements.append(downstream)
+		if self.master is None:
+			self.master = downstream
+	
+	def connectUpstream(self, upstream):
+		self.upstream_elements.append(upstream)
+		self.source = upstream # for single-source elements (i.e., most of them.)
+		self.changed()
+	
+	def connect(self, upstream):
+		self.connectUpstream(upstream)
+		upstream.connectDownstream(self)
+
+	# default action: push downstream
+	def changed(self):
+		self.downstream_elements.changed()