NAME¶
Sub::WrapPackages - add pre- and post-execution wrappers around all the
subroutines in packages or around individual subs
SYNOPSIS¶
use Sub::WrapPackages
packages => [qw(Foo Bar Baz::*)], # wrap all subs in Foo and Bar
# and any Baz::* packages
subs => [qw(Barf::a, Barf::b)], # wrap these two subs as well
wrap_inherited => 1, # and wrap any methods
# inherited by Foo, Bar, or
# Baz::*
pre => sub {
print "called $_[0] with params ".
join(', ', @_[1..$#_])."\n";
},
post => sub {
print "$_[0] returned $_[1]\n";
};
COMPATIBILITY¶
While this module does broadly the same job as the 1.x versions did, the
interface may have changed incompatibly. Sorry. Hopefully it'll be more
maintainable and slightly less crazily magical. Also,
caller() should
now work properly, ignoring wrappings.
DESCRIPTION¶
This module installs pre- and post- execution subroutines for the subroutines or
packages you specify. The pre-execution subroutine is passed the wrapped
subroutine's name and all its arguments. The post-execution subroutine is
passed the wrapped sub's name and its results.
The return values from the pre- and post- subs are ignored, and they are called
in the same context (void, scalar or list) as the calling code asked for.
Normal usage is to pass a bunch of parameters when the module is used. However,
you can also call Sub::WrapPackages::wrapsubs with the same parameters.
PARAMETERS¶
Either pass parameters on loading the module, as above, or pass them to ...
the wrapsubs subroutine¶
- the subs arrayref
- In the synopsis above, you will see two named parameters, "subs"
and "packages". Any subroutine mentioned in "subs"
will be wrapped. Any subroutines mentioned in 'subs' must already exist -
ie their modules must be loaded - at the time you try to wrap them.
- the packages arrayref
- Any package mentioned here will have all its subroutines wrapped,
including any that it imports at load-time. Packages can be loaded in any
order - they don't have to already be loaded for Sub::WrapPackages to work
its magic.
You can specify wildcard packages. Anything ending in ::* is assumed to be
such. For example, if you specify Orchard::Tree::*, then that matches
Orchard::Tree, Orchard::Tree::Pear, Orchard::Apple::KingstonBlack etc, but
not - of course - Pine::Tree or My::Orchard::Tree.
Note, however, that if a module exports a subroutine at load-time using
"import" then that sub will be wrapped in the exporting module
but not in the importing module. This is because import() runs
before we get a chance to fiddle with things. Sorry.
Deferred wrapping of subs in packages that aren't yet loaded works via a
subroutine inserted in @INC. This means that if you mess around with @INC,
eg by inserting a directoy at the beginning of the path, the magic might
not get a chance to run. If you "use lib" to mess with @INC
though, it should work, as I've over-ridden lib's import() method.
That said, code this funky has no right to work. Use with caution!
- wrap_inherited
- In conjunction with the "packages" arrayref, this wraps all
calls to inherited methods made through those packages. If you call those
methods directly in the superclass then they are not affected - unless
they're wrapped in the superclass of course.
- pre and post
- References to the subroutines you want to use as wrappers.
BUGS¶
AUTOLOAD and DESTROY are not treated as being special. I'm not sure whether they
should be or not.
If you use wrap_inherited but classes change their inheritance tree at run-time,
then very bad things will happen. VERY BAD THINGS. So don't do that. You
shouldn't be doing that anyway. Mind you, you shouldn't be doing the things
that this module does either. BAD PROGRAMMER, NO BIKKIT!
If you find any other lurking horrors, please report them using
<
https://rt.cpan.org/Public/Dist/Display.html?Name=Sub-WrapPackages>.
FEEDBACK¶
I like to know who's using my code. All comments, including constructive
criticism, are welcome. Please email me.
SOURCE CODE REPOSITORY¶
<
http://www.cantrell.org.uk/cgit/cgit.cgi/perlmodules/>
COPYRIGHT and LICENCE¶
Copyright 2003-2009 David Cantrell <
david@cantrell.org.uk>
This software is free-as-in-speech software, and may be used, distributed, and
modified under the terms of either the GNU General Public Licence version 2 or
the Artistic Licence. It's up to you which one you use. The full text of the
licences can be found in the files GPL2.txt and ARTISTIC.txt, respectively.
THANKS TO¶
Thanks to Tom Hukins for sending in a test case for the situation when a class
and a subclass are both defined in the same file, and for prompting me to
support inherited methods;
to Dagfinn Ilmari Mannsaker for help with the craziness for fiddling with
modules that haven't yet been loaded;
to Lee Johnson for reporting a bug caused by perl 5.10's constant.pm being Far
Too Clever, and providing a patch and test;
to Adam Trickett who thought this was a jolly good idea;
and to Ed Summers, whose code for figgering out what functions a package
contains I borrowed out of Acme::Voodoo.