IO-Async-0.67HEADIO-Async-0.67master

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diff --git a/lib/IO/Async/Loop/Poll.pm b/lib/IO/Async/Loop/Poll.pm
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+#  You may distribute under the terms of either the GNU General Public License
+#  or the Artistic License (the same terms as Perl itself)
+#
+#  (C) Paul Evans, 2007-2015 -- leonerd@leonerd.org.uk
+
+package IO::Async::Loop::Poll;
+
+use strict;
+use warnings;
+
+our $VERSION = '0.67';
+use constant API_VERSION => '0.49';
+
+use base qw( IO::Async::Loop );
+
+use Carp;
+
+use IO::Poll qw( POLLIN POLLOUT POLLPRI POLLHUP POLLERR );
+
+use Errno qw( EINTR );
+use Fcntl qw( S_ISREG );
+
+# Only Linux, or FreeBSD 8.0 and above, are known always to be able to report
+# EOF conditions on filehandles using POLLHUP
+use constant _CAN_ON_HANGUP =>
+   ( $^O eq "linux" ) ||
+   ( $^O eq "freebsd" and do { no warnings 'numeric'; (POSIX::uname)[2] >= 8.0 } );
+
+# poll() on most platforms claims that ISREG files are always read- and
+# write-ready, but not on MSWin32. We need to fake this
+use constant FAKE_ISREG_READY => IO::Async::OS->HAVE_FAKE_ISREG_READY;
+# poll() on most platforms indicates POLLOUT when connect() fails, but not on
+# MSWin32. Have to poll also for POLLPRI in that case
+use constant POLL_CONNECT_POLLPRI => IO::Async::OS->HAVE_POLL_CONNECT_POLLPRI;
+
+use constant _CAN_WATCHDOG => 1;
+use constant WATCHDOG_ENABLE => IO::Async::Loop->WATCHDOG_ENABLE;
+
+=head1 NAME
+
+C<IO::Async::Loop::Poll> - use C<IO::Async> with C<poll(2)>
+
+=head1 SYNOPSIS
+
+Normally an instance of this class would not be directly constructed by a
+program. It may however, be useful for runinng L<IO::Async> with an existing
+program already using an C<IO::Poll> object.
+
+ use IO::Poll;
+ use IO::Async::Loop::Poll;
+
+ my $poll = IO::Poll->new;
+ my $loop = IO::Async::Loop::Poll->new( poll => $poll );
+
+ $loop->add( ... );
+
+ while(1) {
+    my $timeout = ...
+    my $ret = $poll->poll( $timeout );
+    $loop->post_poll;
+ }
+
+=head1 DESCRIPTION
+
+This subclass of C<IO::Async::Loop> uses the C<poll(2)> system call to perform
+read-ready and write-ready tests.
+
+By default, this loop will use the underlying C<poll()> system call directly,
+bypassing the usual L<IO::Poll> object wrapper around it because of a number
+of bugs and design flaws in that class; namely
+
+=over 2
+
+=item *
+
+L<https://rt.cpan.org/Ticket/Display.html?id=93107> - IO::Poll relies on
+stable stringification of IO handles
+
+=item *
+
+L<https://rt.cpan.org/Ticket/Display.html?id=25049> - IO::Poll->poll() with no
+handles always returns immediately
+
+=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 $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 $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 $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 $msec = defined $timeout ? $timeout * 1000 : -1;
+      my @pollmasks = %{ $self->{pollmask} };
+
+      my $pollret = IO::Poll::_poll( $msec, @pollmasks );
+      if( $pollret == -1 and $! == EINTR or
+          $pollret == 0 and $self->{sigproxy} ) {
+         local $!;
+
+         @pollmasks = %{ $self->{pollmask} };
+         my $secondattempt = IO::Poll::_poll( $msec, @pollmasks );
+         $pollret = $secondattempt if $secondattempt > 0;
+      }
+
+      return undef unless defined $pollret;
+
+      $self->{pollevents} = { @pollmasks };
+      return $self->post_poll;
+   }
+}
+
+sub watch_io
+{
+   my $self = shift;
+   my %params = @_;
+
+   $self->__watch_io( %params );
+
+   my $poll = $self->{poll};
+
+   my $handle = $params{handle};
+   my $fileno = $handle->fileno;
+
+   my $curmask = $poll ? $poll->mask( $handle )
+                       : $self->{pollmask}{$fileno};
+   $curmask ||= 0;
+
+   my $mask = $curmask;
+   $params{on_read_ready}  and $mask |= POLLIN;
+   $params{on_write_ready} and $mask |= POLLOUT | (POLL_CONNECT_POLLPRI ? POLLPRI : 0);
+   $params{on_hangup}      and $mask |= POLLHUP;
+
+   if( FAKE_ISREG_READY and S_ISREG +(stat $handle)[2] ) {
+      $self->{fake_isreg}{$fileno} = $mask;
+   }
+
+   return if $mask == $curmask;
+
+   if( $poll ) {
+      $poll->mask( $handle, $mask );
+   }
+   else {
+      $self->{pollmask}{$fileno} = $mask;
+   }
+}
+
+sub unwatch_io
+{
+   my $self = shift;
+   my %params = @_;
+
+   $self->__unwatch_io( %params );
+
+   my $poll = $self->{poll};
+
+   my $handle = $params{handle};
+   my $fileno = $handle->fileno;
+
+   my $curmask = $poll ? $poll->mask( $handle )
+                       : $self->{pollmask}{$fileno};
+   $curmask ||= 0;
+
+   my $mask = $curmask;
+   $params{on_read_ready}  and $mask &= ~POLLIN;
+   $params{on_write_ready} and $mask &= ~(POLLOUT | (POLL_CONNECT_POLLPRI ? POLLPRI : 0));
+   $params{on_hangup}      and $mask &= ~POLLHUP;
+
+   if( FAKE_ISREG_READY and S_ISREG +(stat $handle)[2] ) {
+      if( $mask ) {
+         $self->{fake_isreg}{$handle->fileno} = $mask;
+      }
+      else {
+         delete $self->{fake_isreg}{$handle->fileno};
+      }
+   }
+
+   return if $mask == $curmask;
+
+   if( $poll ) {
+      $poll->mask( $handle, $mask );
+   }
+   else {
+      $mask ? ( $self->{pollmask}{$fileno} = $mask )
+            : ( delete $self->{pollmask}{$fileno} );
+   }
+}
+
+=head1 AUTHOR
+
+Paul Evans <leonerd@leonerd.org.uk>
+
+=cut
+
+0x55AA;