implement proper 'destroy' functions in Converter

[enigma2.git] / lib / python / Components / Element.py

diff --git a/lib/python/Components/Element.py b/lib/python/Components/Element.py
index 019155c6490482abfbb8cb7933a809edb87afc75..437d934bb507529969571bdeaa487c1503dc825e 100644 (file)
--- a/lib/python/Components/Element.py
+++ b/lib/python/Components/Element.py
@@ -4,6 +4,17 @@ from Tools.CList import CList
 # Render Converter Converter Source
 
 # a bidirectional connection
+
+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
@@ -16,7 +27,7 @@ class Element(object):
                self.master = None
                self.source = None
                self.__suspended = True
-               self.clearCache()
+               self.cache = None
 
        def connectDownstream(self, downstream):
                self.downstream_elements.append(downstream)
@@ -37,11 +48,13 @@ class Element(object):
                # 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:
@@ -52,17 +65,14 @@ class Element(object):
 
        # 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:
@@ -81,3 +91,6 @@ class Element(object):
 
        def doSuspend(self, suspend):
                pass
+
+       def destroy(self):
+               pass