natpunchaffix-pop-only-when-pushed.patch

Index: natdecideraffix.repy
===================================================================
--- natdecideraffix.repy	(revision 7249)
+++ natdecideraffix.repy	(working copy)
@@ -177,36 +177,39 @@
     enable_nat = is_node_behind_nat(localip) 
       
     # Add in the NatPunchAffix if we are behind NAT.
-    # If we are unable to either register, create the NatPunchAffix
-    # or are unable to push the NatPunchAffix onto the stack, we
-    # just move on and not use the NatPunchAffix.
+    # If we are unable to either register or create the NatPunchAffix, 
+    # are unable to push it onto the stack, or listen on it, we just 
+    # move on and not use the NatPunchAffix.
+
     if enable_nat:
       try:
         find_and_register_affix("NatPunchAffix")
         nat_affix = create_affix_object("NatPunchAffix", [], None)
-        
-        # Now we push the new NatPunchAffix onto our stack.
-        self.push(nat_affix)
       except (AffixNotFoundError, AffixStackError), e:
-        # Remove the current (void) NatPunchAffix from the stack.
-        self.pop()
-      except Exception, e:
-        # Remove the current (void) NatPunchAffix from the stack.
-        self.pop()
-        raise
+        # find_and_register_affix or instantiation failed. Continue 
+        # outside of the ``if'' clause without the Affix in place.
+        pass
+      else:
+        # We found, registered, and instantiated the NatPunchAffix.
+        try:
+	  self.push(nat_affix)
+          tcpserversocket = self.peek().listenforconnection(localip, localport)
+        except:
+          # Pushing or actually listening didn't work. Try below 
+          # without the NatPunchAffix.
+          self.pop()
+        else:
+          # All is well, the NatPunchAffix listens for connection. Return it!
+          return AffixTCPServerSocket(tcpserversocket, self)
 
-    # If we reach this point, we either got the NatPunchAffix registered, 
-    # or decided we don't need one.
+    # If we reach this point, we didn't find/get the NatPunchAffix registered, 
+    # failed trying to push it or listen on it, or decided we don't need one.
     try:
       tcpserversocket = self.peek().listenforconnection(localip, localport)
     except AttributeError, e:
       # Hmm, looks like the object has no peek(). It's probably a 
       # RepyNetworkApiWrapper, not an Affix. Go without peek() then.
       tcpserversocket = self.listenforconnection(localip, localport)
-    except Exception, e:
-      # The NatPunchAffix we just pushed gave us this error. Remove it!
-      self.pop()
-      raise
 
     # If we reach this point, all went well
     return AffixTCPServerSocket(tcpserversocket, self)