to subclass, or not to subclass...

[Ben Johnson <ben blarg net>]

I need some advice.  I'm used to working in C, so I'm not used to making
decisions about when to create sub-classes and when I should just use
callbacks.

One feature of the app I'm making is a global inactivity timer.  When
the timer goes off the app does a locked screen saver kind of thing.
The way I've made this work so far is by adding a call to a function at
the start of almost every callback.  The only callbacks that don't reset
the inactivity timer are those triggered when the user is attempting to
unlock the app.

So, you probably know what I'm going to ask.  It seems like it might be
easier to maintain and more reliable to (instead of adding cookie cutter
code to every callback) subclass every widget and overwrite every signal
in those widgets that I want to reset the timer.  Is that a no-brainer?
I could add other code in these shims as well such as security/consistency
checks or functions that log all events if a debug/security level is
turned up high enough, etc.. (I'm making a POS.)

I've used Glade to do most of the layout and design work so far.  I
don't know if that has to influence my decision.  It is a large app with
lots of callbacks.  What would you do?

Thanks,

- Ben