CHI (http://search.cpan.org/~jswartz/CHI-0.091/lib/CHI.pm) is a Moose-
based caching framework. There is a driver superclass (CHI::Driver)
and various driver subclasses that implement different cache backends
(CHI::Driver::File, CHI::Driver::Memcached, etc.) Drivers implement
standard methods like remove() and clear(). e.g Currently, if you call
$cache->remove(), it goes directly to the driver subclass.
The problem is that there are now legitimate reasons to "wrap" these
methods at the CHI/Driver.pm superclass level (meaning, do something
before and/or after the method). For example, I want to add an
optional generic size-awareness feature (the cache can keep track of
its own size), which means that we have to adjust size whenever
remove() and clear() are called. And I want to log remove() calls the
way we currently log get() and set().
So one solution is to define remove() and clear() in CHI/Driver.pm,
and have them call _remove() and _clear() in the driver subclasses.
But this kind of change makes me uneasy for several reasons:
* It changes the driver API, i.e. all existing drivers out there have
to modified. And we might have to change it again as we identify new
methods to wrap.
* The list of 'normal' versus 'underscore' methods becomes rather
arbitrary - it's "whatever we've needed to wrap so far".
Moose has before & after modifiers, but can they be defined in the
superclass and affect the subclass??
I guess CHI.pm could use a wrapping module, like Sub::Prepend or
Hook::LexWrap, on any driver class the first time it is used, e.g. the
first time someone says
CHI->new(driver => 'File')
we wrap the appropriate File methods. But this feels hacky - these
tools seem like a way to modify someone else's module, not as a
standard part of your own class.
Advice appreciated!
Thanks
Jon
