On Mon, Jun 20, 2005 at 01:38:42PM -0400, Sam Tregar wrote:
> On Mon, 20 Jun 2005, Tim Bunce wrote:
>
> > > Can you suggest a good
> > > place to put the code to collect open handles? Knowing nothing about
> > > the internals I'm guessing connect() is the right spot.
> >
> > Actually _new_handle() in DBI.pm
> >
> > But first we need an API. A reasonable first draft would be to add a
> > $h->{ChildHandles} attribute that's a hash where the values of the hash
> > are the child handles. (The keys of the hash are irrelevant but unique.
> > The hash will have undef elements for any old handles that have been
> > destroyed so we'll need to prune them occasionally, but that can wait.)
>
> That sounds like a start, but how would I get that hash if I didn't
> have a handle to start with? I'm imagining:
>
> $handles = DBI->ChildHandles();
$drh = DBI->install_driver('mysql');
$all_mysql_dbh = $drh->{ChildHandles};
(install_driver doesn't reinstall the driver if it's already loaded)
> But I'm not sure I understand what "child" means in this context.
> Perhaps:
>
> $handles = $dbh->{ActiveHandles};
> $handles = DBI->ActiveHandles();
>
> That implies that the hash that comes back would be stripped of
> inactive handles which sounds like a good things to me.
Perhaps but let's keep it very simple to start with - just the attribute.
> > So, given that API, you could start by trying something like this:
> >
> > weaken($parent->{ChildHandles}{$h} = $h);
> >
> > just after the call to DBI::_setup_handle($h, $imp_class, $parent,
> > $imp_data);
> > You'll need a use Scalar::Util qw(weaken); at the top.
>
> Sounds right. We'll need to do a probe for weaken() support though
> (Redhat, in its infinite wisdom, shipped Perl 5.6.x without weaken()
> in one of their distros). Would you rather have it at install-time or
> run-time?
Try something like this near the top of DBI.pm
my $have_weaken = eval { require Scalar::Util; defined &Scalar::Util::weaken };
then
Scalar::Util::weaken(...) if $have_weaken;
> > That's a basic hack that might work well enough for you to write some
> > tests that pass (add a new t/71childh.t test file).
>
> Will do.
>
> Thanks for the help! If there's ever a ballot for best CPAN
> maintainer you've got my vote.
Thanks! I always feel there's so much more I could be doing.
What I need to do is try to open up the process more so others can
contribute - which is where you come in :-)
Tim.
