view release on metacpan or  search on metacpan

local/lib/perl5/IO/Async/Loop/Poll.pm  view on Meta::CPAN

=back

However, to integrate with existing code that uses an C<IO::Poll> object, a
C<post_poll> can be called immediately after the C<poll> method that
C<IO::Poll> object. The appropriate mask bits are maintained on the
C<IO::Poll> object when notifiers are added or removed from the loop, or when
they change their C<want_*> status. The C<post_poll> method inspects the
result bits and invokes the C<on_read_ready> or C<on_write_ready> methods on
the notifiers.

=cut

=head1 CONSTRUCTOR

=cut

=head2 new

   $loop = IO::Async::Loop::Poll->new( %args )

This function returns a new instance of a C<IO::Async::Loop::Poll> object. It
takes the following named arguments:

=over 8

=item C<poll>

The C<IO::Poll> object to use for notification. Optional; if a value is not
given, the underlying C<IO::Poll::_poll()> function is invoked directly,
outside of the object wrapping.

=back

=cut

sub new
{
   my $class = shift;
   my ( %args ) = @_;

   my $poll = delete $args{poll};

   my $self = $class->__new( %args );

   $self->{poll} = $poll;
   $self->{pollmask} = {};

   return $self;
}

=head1 METHODS

=cut

=head2 post_poll

   $count = $loop->post_poll

This method checks the returned event list from a C<IO::Poll::poll> call,
and calls any of the notification methods or callbacks that are appropriate.
It returns the total number of callbacks that were invoked; that is, the
total number of C<on_read_ready> and C<on_write_ready> callbacks for 
C<watch_io>, and C<watch_time> event callbacks.

=cut

sub post_poll
{
   my $self = shift;

   my $iowatches = $self->{iowatches};
   my $poll      = $self->{poll};

   my $count = 0;

   alarm( IO::Async::Loop->WATCHDOG_INTERVAL ) if WATCHDOG_ENABLE;

   foreach my $fd ( keys %$iowatches ) {
      my $watch = $iowatches->{$fd} or next;

      my $events = $poll ? $poll->events( $watch->[0] )
                         : $self->{pollevents}{$fd};
      if( FAKE_ISREG_READY and $self->{fake_isreg}{$fd} ) {
         $events |= $self->{fake_isreg}{$fd} & ( POLLIN|POLLOUT );
      }

      # We have to test separately because kernel doesn't report POLLIN when
      # a pipe gets closed.
      if( $events & (POLLIN|POLLHUP|POLLERR) ) {
         $count++, $watch->[1]->() if defined $watch->[1];
      }

      if( $events & (POLLOUT|POLLPRI|POLLHUP|POLLERR) ) {
         $count++, $watch->[2]->() if defined $watch->[2];
      }

      if( $events & (POLLHUP|POLLERR) ) {
         $count++, $watch->[3]->() if defined $watch->[3];
      }
   }

   # Since we have no way to know if the timeout occured, we'll have to
   # attempt to fire any waiting timeout events anyway
   $count += $self->_manage_queues;

   alarm( 0 ) if WATCHDOG_ENABLE;

   return $count;
}

=head2 loop_once

   $count = $loop->loop_once( $timeout )

This method calls the C<poll> method on the stored C<IO::Poll> object,
passing in the value of C<$timeout>, and then runs the C<post_poll> method
on itself. It returns the total number of callbacks invoked by the 
C<post_poll> method, or C<undef> if the underlying C<poll> method returned
an error.

=cut

sub loop_once
{
   my $self = shift;
   my ( $timeout ) = @_;

   $self->_adjust_timeout( \$timeout );

   $timeout = 0 if FAKE_ISREG_READY and keys %{ $self->{fake_isreg} };

   # Round up to nearest millisecond
   if( $timeout ) {
      my $mils = $timeout * 1000;
      my $fraction = $mils - int $mils;
      $timeout += ( 1 - $fraction ) / 1000 if $fraction;
   }

   if( my $poll = $self->{poll} ) {
      my $pollret;

      # There is a bug in IO::Poll at least version 0.07, where poll with no
      # registered masks returns immediately, rather than waiting for a timeout
      # This has been reported: 
      #   http://rt.cpan.org/Ticket/Display.html?id=25049
      if( $poll->handles ) {
         $pollret = $poll->poll( $timeout );

         if( ( $pollret == -1 and $! == EINTR ) or $pollret == 0 
                 and defined $self->{sigproxy} ) {
            # A signal occured and we have a sigproxy. Allow one more poll call
            # with zero timeout. If it finds something, keep that result. If it
            # finds nothing, keep -1

            # Preserve $! whatever happens
            local $!;

            my $secondattempt = $poll->poll( 0 );
            $pollret = $secondattempt if $secondattempt > 0;
         }
      }
      else {
         # Workaround - we'll use select to fake a millisecond-accurate sleep
         $pollret = select( undef, undef, undef, $timeout );
      }

      return undef unless defined $pollret;
      return $self->post_poll;
   }
   else {
      my @pollmasks = %{ $self->{pollmask} };

      # Perl 5.8.x's IO::Poll::_poll gets confused with no masks
      my $pollret;
      if( @pollmasks ) {
         my $msec = defined $timeout ? $timeout * 1000 : -1;
         $pollret = IO::Poll::_poll( $msec, @pollmasks );