X-Git-Url: https://git.cweiske.de/enigma2.git/blobdiff_plain/1557c715e461d5a7deb04bb008c6497441351bbe..194615a88fac0c4259b3c2217c8e13372b7c3b86:/lib/python/Components/Element.py

diff --git a/lib/python/Components/Element.py b/lib/python/Components/Element.py
index 12218466..437d934b 100644
--- a/lib/python/Components/Element.py
+++ b/lib/python/Components/Element.py
@@ -4,7 +4,18 @@ from Tools.CList import CList
 # Render Converter Converter Source
 
 # a bidirectional connection
-class Element:
+
+def cached(f):
+	name = f.__name__
+	def wrapper(self):
+		if self.cache is None:
+			return f(self)
+		if name not in self.cache:
+			self.cache[name] = (True, f(self))
+		return self.cache[name][1]
+	return wrapper
+
+class Element(object):
 	CHANGED_DEFAULT = 0   # initial "pull" state
 	CHANGED_ALL = 1       # really everything changed
 	CHANGED_CLEAR = 2     # we're expecting a real update soon. don't bother polling NOW, but clear data.
@@ -15,7 +26,8 @@ class Element:
 		self.downstream_elements = CList()
 		self.master = None
 		self.source = None
-		self.clearCache()
+		self.__suspended = True
+		self.cache = None
 
 	def connectDownstream(self, downstream):
 		self.downstream_elements.append(downstream)
@@ -36,11 +48,13 @@ class Element:
 		# 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"
-		
+
 		# Sources don't have a source themselves. don't do anything here.
 		if self.source is not None:
 			self.source.disconnectDownstream(self)
-	
+			# sources are owned by the Screen, so don't destroy them here.
+			self.destroy()
+
 	def disconnectDownstream(self, downstream):
 		self.downstream_elements.remove(downstream)
 		if self.master == downstream:
@@ -51,13 +65,32 @@ class Element:
 
 	# default action: push downstream
 	def changed(self, *args, **kwargs):
-		self.clearCache()
+		self.cache = { }
 		self.downstream_elements.changed(*args, **kwargs)
-		self.clearCache()
+		self.cache = None
 
 	def reconnectUpstream(self, new_upstream):
 		assert self.source is not None
 		self.source = new_upstream
 
-	def clearCache(self):
-		self.cache = None
+	def setSuspend(self, suspended):
+		changed = self.__suspended != suspended
+		if not self.__suspended and suspended:
+			self.doSuspend(1)
+		elif self.__suspended and not suspended:
+			self.doSuspend(0)
+			
+		self.__suspended = suspended
+		if self.source is not None and changed:
+			self.source.checkSuspend()
+	
+	suspended = property(lambda self: self.__suspended, setSuspend)
+	
+	def checkSuspend(self):
+		self.suspended = reduce(lambda x, y: x and y.__suspended, self.downstream_elements, True)
+
+	def doSuspend(self, suspend):
+		pass
+
+	def destroy(self):
+		pass