view release on metacpan or  search on metacpan

lib/POE/Resource/Extrefs.pm  view on Meta::CPAN

# The data necessary to manage tagged extra/external reference counts
# on sessions, and the accessors to get at them sanely from other
# files.

package POE::Resource::Extrefs;

use vars qw($VERSION);
$VERSION = '1.370'; # NOTE - Should be #.### (three decimal places)

# These methods are folded into POE::Kernel;
package POE::Kernel;

use strict;

### The count of all extra references used in the system.

my %kr_extra_refs;
#  ( $session_id =>
#    { $tag => $count,
#       ...,
#     },
#     ...,
#   );

sub _data_extref_relocate_kernel_id {
  my ($self, $old_id, $new_id) = @_;
  return unless exists $kr_extra_refs{$old_id};
  $kr_extra_refs{$new_id} = delete $kr_extra_refs{$old_id};
}

### End-run leak checking.

sub _data_extref_finalize {
  my $finalized_ok = 1;
  foreach my $session_id (keys %kr_extra_refs) {
    $finalized_ok = 0;
    _warn "!!! Leaked extref: $session_id\n";
    foreach my $tag (keys %{$kr_extra_refs{$session_id}}) {
      _warn "!!!\t`$tag' = $kr_extra_refs{$session_id}->{$tag}\n";
    }
  }
  return $finalized_ok;
}

# Increment a session's tagged reference count.  If this is the first
# time the tag is used in the session, then increment the session's
# reference count as well.  Returns the tag's new reference count.
#
# TODO Allows incrementing reference counts on sessions that don't
# exist, but the public interface catches that.
#
# TODO Need to track extref ownership for signal-based session
# termination.  One problem seen is that signals terminate sessions
# out of order.  Owners think extra refcounts exist for sessions that
# are no longer around.  Ownership trees give us a few benefits: We
# can make sure sessions destruct in a cleaner order.  We can detect
# refcount loops and possibly prevent that.

sub _data_extref_inc {
  my ($self, $sid, $tag) = @_;
  my $refcount = ++$kr_extra_refs{$sid}->{$tag};

  # TODO We could probably get away with only incrementing the
  # session's master refcount once, as long as any extra refcount is
  # positive.  Then the session reference count would be a flag
  # instead of a counter.
  $self->_data_ses_refcount_inc($sid) if $refcount == 1;

  if (TRACE_REFCNT) {
    _warn(
      "<rc> incremented extref ``$tag'' (now $refcount) for ",
      $self->_data_alias_loggable($sid)
    );
  }

  return $refcount;
}

# Decrement a session's tagged reference count, removing it outright
# if the count reaches zero.  Return the new reference count or undef
# if the tag doesn't exist.
#
# TODO Allows negative reference counts, and the resulting hilarity.
# Hopefully the public interface won't allow it.