pitivi r1371 - trunk/pitivi

[edwardrv svn gnome org]

Author: edwardrv
Date: Fri Nov 28 17:03:57 2008
New Revision: 1371
URL: http://svn.gnome.org/viewvc/pitivi?rev=1371&view=rev

Log:
added receiver module

Added:
   trunk/pitivi/receiver.py

Added: trunk/pitivi/receiver.py
==============================================================================
--- (empty file)
+++ trunk/pitivi/receiver.py	Fri Nov 28 17:03:57 2008
@@ -0,0 +1,56 @@
+def handler(attribute, signal):
+    """Registers a method in a subclass of receiver as a handler"""
+    def decorator(method):
+        method.__sender__ = attribute
+        method.__signal__ = signal
+        return method
+    return decorator
+
+def set_sender(attrname):
+
+    def inner(self, new_instance):
+        # get the attribute
+        attr = self.__senders__[attrname]
+        if attr:
+            # disconnect all the previous signal handlers
+            for sigid in self.__sigids__[attrname].itervalues():
+                attr.disconnect(sigid)
+            setattr(self, attr, None)
+        if new_instance:
+            # save the instance
+            self.__senders__[attrname]
+            for signal, handler in self.__handlers__[attrname].iteritems():
+                self.__sigids__[attrname][signal] = new_instance.connect(signal, 
+                    handler)
+    inner.__name__ = "set_" + attrname
+    return inner
+
+def get_sender(attrname):
+    def inner(self):
+        return self.__senders__[attrname]
+    inner.__name__ = "get_" + attrname
+    return inner
+
+class ReceiverMeta(type):
+
+    def __new__(meta, classname, bases, attributes):
+        handlers = {}
+        out = dict(attributes)
+        for attrname, value in attributes.iteritems():
+            if hasattr(value, "__sender__") and hasattr(value, "__signal__"):
+                sender = value.__sender__
+                signal = value.__signal__
+                handlers.setdefault(sender, {})[signal] = value
+                out[sender] = property(get_sender(sender),
+                    set_sender(sender))
+        out["__handlers__"] = handlers
+        out["__sigids__"] = {}
+        return type.__new__(meta, classname, bases, out)
+
+class Receiver(object):
+
+    """Automatically connects appropriate signal handler methods to attributes
+    designated as "senders". Subclasses simply declare signal handler methods
+    with the @receiver.handler(<attribute>, <signal>)"""
+
+    __metaclass__ = ReceiverMeta