Stas Bekman <[EMAIL PROTECTED]> writes:
[...]
> There are going to be various tricky bugs to figure out with the new
> things. I just had one when I tried:
>
> perl -MApache2 -MAPR::Pool -MAPR::PerlIO -le '; open my $fh, "<:APR",
> "/tmp/xxx", APR::Pool->new; print <$fh>'
> APR::PerlIO::read: (9) Bad file descriptor at -e line ...
>
> it took me time to figure out that the pool has gone out of scope and
> was destroyed by the time read was attempted.
Yup- it took me a few reads to even understand the problem
you had :-).
> This fixed the problem:
>
> perl -MApache2 -MAPR::Pool -MAPR::PerlIO -le '; my $p =
> APR::Pool->new; open my $fh, "<:APR", "/tmp/xxx", $p; print <$fh>'
>
> tricky. We may need to have much more defending code if we don't want
> to get a rain of bug reports. And writing it is not trivial at all :(
>
> so in the case of open() we probably need to increment the refcount
> of the pool object and decrement it on close and hope that we don't
> get a leak anywhere.
The problem is the same for any pool-derived object,
e.g.
#! perl
use Apache2;
use APR::Pool;
use Apache::Request;
my $req = Apache::Request->new(APR::Pool->new);
print $req->param; #KaBoom!
In apreq we don't currently tag the pool SV that constructed us,
so a DESTROY method can't decrement it. We could change that in
apreq2,but doing that throughout mp2 might be messy.
Is it possible to do something within APR::Pool
to address this? Maybe calling APR::Pool->new()
can dish out pool objects from an internal list:
package APR::Pool;
sub new {
my $parent = shift;
if (!ref $parent) {
my $pool = <new APR::Pool object>;
push @INTERNAL_POOL_LIST, $pool;
return $pool;
}
...
sub DESTROY {
my $pool = shift;
if (!ref $pool) {
pop @INTERNAL_POOL_LIST;
}
}
Here somebody would need to call APR::Pool->DESTROY
to actually relinquish the last pool. Conway's OOP
book discusses the "flyweight pattern", which probably
has much better ideas than this.
--
Joe Schaefer
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