ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/AnyEvent/lib/AnyEvent.pm
(Generate patch)

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.219 by root, Thu Jun 25 11:16:08 2009 UTC vs.
Revision 1.240 by root, Fri Jul 17 14:57:03 2009 UTC

176=head2 I/O WATCHERS 176=head2 I/O WATCHERS
177 177
178You can create an I/O watcher by calling the C<< AnyEvent->io >> method 178You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179with the following mandatory key-value pairs as arguments: 179with the following mandatory key-value pairs as arguments:
180 180
181C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch 181C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182for events (AnyEvent might or might not keep a reference to this file 182for events (AnyEvent might or might not keep a reference to this file
183handle). Note that only file handles pointing to things for which 183handle). Note that only file handles pointing to things for which
184non-blocking operation makes sense are allowed. This includes sockets, 184non-blocking operation makes sense are allowed. This includes sockets,
185most character devices, pipes, fifos and so on, but not for example files 185most character devices, pipes, fifos and so on, but not for example files
186or block devices. 186or block devices.
463 463
464If you are familiar with some event loops you will know that all of them 464If you are familiar with some event loops you will know that all of them
465require you to run some blocking "loop", "run" or similar function that 465require you to run some blocking "loop", "run" or similar function that
466will actively watch for new events and call your callbacks. 466will actively watch for new events and call your callbacks.
467 467
468AnyEvent is different, it expects somebody else to run the event loop and 468AnyEvent is slightly different: it expects somebody else to run the event
469will only block when necessary (usually when told by the user). 469loop and will only block when necessary (usually when told by the user).
470 470
471The instrument to do that is called a "condition variable", so called 471The instrument to do that is called a "condition variable", so called
472because they represent a condition that must become true. 472because they represent a condition that must become true.
473 473
474Now is probably a good time to look at the examples further below.
475
474Condition variables can be created by calling the C<< AnyEvent->condvar 476Condition variables can be created by calling the C<< AnyEvent->condvar
475>> method, usually without arguments. The only argument pair allowed is 477>> method, usually without arguments. The only argument pair allowed is
476
477C<cb>, which specifies a callback to be called when the condition variable 478C<cb>, which specifies a callback to be called when the condition variable
478becomes true, with the condition variable as the first argument (but not 479becomes true, with the condition variable as the first argument (but not
479the results). 480the results).
480 481
481After creation, the condition variable is "false" until it becomes "true" 482After creation, the condition variable is "false" until it becomes "true"
530 after => 1, 531 after => 1,
531 cb => sub { $result_ready->send }, 532 cb => sub { $result_ready->send },
532 ); 533 );
533 534
534 # this "blocks" (while handling events) till the callback 535 # this "blocks" (while handling events) till the callback
535 # calls send 536 # calls -<send
536 $result_ready->recv; 537 $result_ready->recv;
537 538
538Example: wait for a timer, but take advantage of the fact that 539Example: wait for a timer, but take advantage of the fact that condition
539condition variables are also code references. 540variables are also callable directly.
540 541
541 my $done = AnyEvent->condvar; 542 my $done = AnyEvent->condvar;
542 my $delay = AnyEvent->timer (after => 5, cb => $done); 543 my $delay = AnyEvent->timer (after => 5, cb => $done);
543 $done->recv; 544 $done->recv;
544 545
550 551
551 ... 552 ...
552 553
553 my @info = $couchdb->info->recv; 554 my @info = $couchdb->info->recv;
554 555
555And this is how you would just ste a callback to be called whenever the 556And this is how you would just set a callback to be called whenever the
556results are available: 557results are available:
557 558
558 $couchdb->info->cb (sub { 559 $couchdb->info->cb (sub {
559 my @info = $_[0]->recv; 560 my @info = $_[0]->recv;
560 }); 561 });
578immediately from within send. 579immediately from within send.
579 580
580Any arguments passed to the C<send> call will be returned by all 581Any arguments passed to the C<send> call will be returned by all
581future C<< ->recv >> calls. 582future C<< ->recv >> calls.
582 583
583Condition variables are overloaded so one can call them directly 584Condition variables are overloaded so one can call them directly (as if
584(as a code reference). Calling them directly is the same as calling 585they were a code reference). Calling them directly is the same as calling
585C<send>. Note, however, that many C-based event loops do not handle 586C<send>.
586overloading, so as tempting as it may be, passing a condition variable
587instead of a callback does not work. Both the pure perl and EV loops
588support overloading, however, as well as all functions that use perl to
589invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590example).
591 587
592=item $cv->croak ($error) 588=item $cv->croak ($error)
593 589
594Similar to send, but causes all call's to C<< ->recv >> to invoke 590Similar to send, but causes all call's to C<< ->recv >> to invoke
595C<Carp::croak> with the given error message/object/scalar. 591C<Carp::croak> with the given error message/object/scalar.
596 592
597This can be used to signal any errors to the condition variable 593This can be used to signal any errors to the condition variable
598user/consumer. 594user/consumer. Doing it this way instead of calling C<croak> directly
595delays the error detetcion, but has the overwhelmign advantage that it
596diagnoses the error at the place where the result is expected, and not
597deep in some event clalback without connection to the actual code causing
598the problem.
599 599
600=item $cv->begin ([group callback]) 600=item $cv->begin ([group callback])
601 601
602=item $cv->end 602=item $cv->end
603
604These two methods are EXPERIMENTAL and MIGHT CHANGE.
605 603
606These two methods can be used to combine many transactions/events into 604These two methods can be used to combine many transactions/events into
607one. For example, a function that pings many hosts in parallel might want 605one. For example, a function that pings many hosts in parallel might want
608to use a condition variable for the whole process. 606to use a condition variable for the whole process.
609 607
611C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 609C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
612>>, the (last) callback passed to C<begin> will be executed. That callback 610>>, the (last) callback passed to C<begin> will be executed. That callback
613is I<supposed> to call C<< ->send >>, but that is not required. If no 611is I<supposed> to call C<< ->send >>, but that is not required. If no
614callback was set, C<send> will be called without any arguments. 612callback was set, C<send> will be called without any arguments.
615 613
616Let's clarify this with the ping example: 614You can think of C<< $cv->send >> giving you an OR condition (one call
615sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
616condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617
618Let's start with a simple example: you have two I/O watchers (for example,
619STDOUT and STDERR for a program), and you want to wait for both streams to
620close before activating a condvar:
621
622 my $cv = AnyEvent->condvar;
623
624 $cv->begin; # first watcher
625 my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
626 defined sysread $fh1, my $buf, 4096
627 or $cv->end;
628 });
629
630 $cv->begin; # second watcher
631 my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
632 defined sysread $fh2, my $buf, 4096
633 or $cv->end;
634 });
635
636 $cv->recv;
637
638This works because for every event source (EOF on file handle), there is
639one call to C<begin>, so the condvar waits for all calls to C<end> before
640sending.
641
642The ping example mentioned above is slightly more complicated, as the
643there are results to be passwd back, and the number of tasks that are
644begung can potentially be zero:
617 645
618 my $cv = AnyEvent->condvar; 646 my $cv = AnyEvent->condvar;
619 647
620 my %result; 648 my %result;
621 $cv->begin (sub { $cv->send (\%result) }); 649 $cv->begin (sub { $cv->send (\%result) });
641loop, which serves two important purposes: first, it sets the callback 669loop, which serves two important purposes: first, it sets the callback
642to be called once the counter reaches C<0>, and second, it ensures that 670to be called once the counter reaches C<0>, and second, it ensures that
643C<send> is called even when C<no> hosts are being pinged (the loop 671C<send> is called even when C<no> hosts are being pinged (the loop
644doesn't execute once). 672doesn't execute once).
645 673
646This is the general pattern when you "fan out" into multiple subrequests: 674This is the general pattern when you "fan out" into multiple (but
647use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 675potentially none) subrequests: use an outer C<begin>/C<end> pair to set
648is called at least once, and then, for each subrequest you start, call 676the callback and ensure C<end> is called at least once, and then, for each
649C<begin> and for each subrequest you finish, call C<end>. 677subrequest you start, call C<begin> and for each subrequest you finish,
678call C<end>.
650 679
651=back 680=back
652 681
653=head3 METHODS FOR CONSUMERS 682=head3 METHODS FOR CONSUMERS
654 683
670function will call C<croak>. 699function will call C<croak>.
671 700
672In list context, all parameters passed to C<send> will be returned, 701In list context, all parameters passed to C<send> will be returned,
673in scalar context only the first one will be returned. 702in scalar context only the first one will be returned.
674 703
704Note that doing a blocking wait in a callback is not supported by any
705event loop, that is, recursive invocation of a blocking C<< ->recv
706>> is not allowed, and the C<recv> call will C<croak> if such a
707condition is detected. This condition can be slightly loosened by using
708L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
709any thread that doesn't run the event loop itself.
710
675Not all event models support a blocking wait - some die in that case 711Not all event models support a blocking wait - some die in that case
676(programs might want to do that to stay interactive), so I<if you are 712(programs might want to do that to stay interactive), so I<if you are
677using this from a module, never require a blocking wait>, but let the 713using this from a module, never require a blocking wait>. Instead, let the
678caller decide whether the call will block or not (for example, by coupling 714caller decide whether the call will block or not (for example, by coupling
679condition variables with some kind of request results and supporting 715condition variables with some kind of request results and supporting
680callbacks so the caller knows that getting the result will not block, 716callbacks so the caller knows that getting the result will not block,
681while still supporting blocking waits if the caller so desires). 717while still supporting blocking waits if the caller so desires).
682 718
683Another reason I<never> to C<< ->recv >> in a module is that you cannot
684sensibly have two C<< ->recv >>'s in parallel, as that would require
685multiple interpreters or coroutines/threads, none of which C<AnyEvent>
686can supply.
687
688The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
689fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
690versions and also integrates coroutines into AnyEvent, making blocking
691C<< ->recv >> calls perfectly safe as long as they are done from another
692coroutine (one that doesn't run the event loop).
693
694You can ensure that C<< -recv >> never blocks by setting a callback and 719You can ensure that C<< -recv >> never blocks by setting a callback and
695only calling C<< ->recv >> from within that callback (or at a later 720only calling C<< ->recv >> from within that callback (or at a later
696time). This will work even when the event loop does not support blocking 721time). This will work even when the event loop does not support blocking
697waits otherwise. 722waits otherwise.
698 723
711variable itself. Calling C<recv> inside the callback or at any later time 736variable itself. Calling C<recv> inside the callback or at any later time
712is guaranteed not to block. 737is guaranteed not to block.
713 738
714=back 739=back
715 740
741=head1 SUPPORTED EVENT LOOPS/BACKENDS
742
743The available backend classes are (every class has its own manpage):
744
745=over 4
746
747=item Backends that are autoprobed when no other event loop can be found.
748
749EV is the preferred backend when no other event loop seems to be in
750use. If EV is not installed, then AnyEvent will try Event, and, failing
751that, will fall back to its own pure-perl implementation, which is
752available everywhere as it comes with AnyEvent itself.
753
754 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
755 AnyEvent::Impl::Event based on Event, very stable, few glitches.
756 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
757
758=item Backends that are transparently being picked up when they are used.
759
760These will be used when they are currently loaded when the first watcher
761is created, in which case it is assumed that the application is using
762them. This means that AnyEvent will automatically pick the right backend
763when the main program loads an event module before anything starts to
764create watchers. Nothing special needs to be done by the main program.
765
766 AnyEvent::Impl::Glib based on Glib, slow but very stable.
767 AnyEvent::Impl::Tk based on Tk, very broken.
768 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
769 AnyEvent::Impl::POE based on POE, very slow, some limitations.
770
771=item Backends with special needs.
772
773Qt requires the Qt::Application to be instantiated first, but will
774otherwise be picked up automatically. As long as the main program
775instantiates the application before any AnyEvent watchers are created,
776everything should just work.
777
778 AnyEvent::Impl::Qt based on Qt.
779
780Support for IO::Async can only be partial, as it is too broken and
781architecturally limited to even support the AnyEvent API. It also
782is the only event loop that needs the loop to be set explicitly, so
783it can only be used by a main program knowing about AnyEvent. See
784L<AnyEvent::Impl::Async> for the gory details.
785
786 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
787
788=item Event loops that are indirectly supported via other backends.
789
790Some event loops can be supported via other modules:
791
792There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
793
794B<WxWidgets> has no support for watching file handles. However, you can
795use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
796polls 20 times per second, which was considered to be too horrible to even
797consider for AnyEvent.
798
799B<Prima> is not supported as nobody seems to be using it, but it has a POE
800backend, so it can be supported through POE.
801
802AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
803load L<POE> when detecting them, in the hope that POE will pick them up,
804in which case everything will be automatic.
805
806=back
807
716=head1 GLOBAL VARIABLES AND FUNCTIONS 808=head1 GLOBAL VARIABLES AND FUNCTIONS
717 809
810These are not normally required to use AnyEvent, but can be useful to
811write AnyEvent extension modules.
812
718=over 4 813=over 4
719 814
720=item $AnyEvent::MODEL 815=item $AnyEvent::MODEL
721 816
722Contains C<undef> until the first watcher is being created. Then it 817Contains C<undef> until the first watcher is being created, before the
818backend has been autodetected.
819
723contains the event model that is being used, which is the name of the 820Afterwards it contains the event model that is being used, which is the
724Perl class implementing the model. This class is usually one of the 821name of the Perl class implementing the model. This class is usually one
725C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 822of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
726AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 823case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
727 824will be C<urxvt::anyevent>).
728The known classes so far are:
729
730 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
731 AnyEvent::Impl::Event based on Event, second best choice.
732 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
733 AnyEvent::Impl::Glib based on Glib, third-best choice.
734 AnyEvent::Impl::Tk based on Tk, very bad choice.
735 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
736 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
737 AnyEvent::Impl::POE based on POE, not generic enough for full support.
738
739 # warning, support for IO::Async is only partial, as it is too broken
740 # and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
741 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
742
743There is no support for WxWidgets, as WxWidgets has no support for
744watching file handles. However, you can use WxWidgets through the
745POE Adaptor, as POE has a Wx backend that simply polls 20 times per
746second, which was considered to be too horrible to even consider for
747AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
748it's adaptor.
749
750AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
751autodetecting them.
752 825
753=item AnyEvent::detect 826=item AnyEvent::detect
754 827
755Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 828Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
756if necessary. You should only call this function right before you would 829if necessary. You should only call this function right before you would
757have created an AnyEvent watcher anyway, that is, as late as possible at 830have created an AnyEvent watcher anyway, that is, as late as possible at
758runtime. 831runtime, and not e.g. while initialising of your module.
832
833If you need to do some initialisation before AnyEvent watchers are
834created, use C<post_detect>.
759 835
760=item $guard = AnyEvent::post_detect { BLOCK } 836=item $guard = AnyEvent::post_detect { BLOCK }
761 837
762Arranges for the code block to be executed as soon as the event model is 838Arranges for the code block to be executed as soon as the event model is
763autodetected (or immediately if this has already happened). 839autodetected (or immediately if this has already happened).
840
841The block will be executed I<after> the actual backend has been detected
842(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
843created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
844other initialisations - see the sources of L<AnyEvent::Strict> or
845L<AnyEvent::AIO> to see how this is used.
846
847The most common usage is to create some global watchers, without forcing
848event module detection too early, for example, L<AnyEvent::AIO> creates
849and installs the global L<IO::AIO> watcher in a C<post_detect> block to
850avoid autodetecting the event module at load time.
764 851
765If called in scalar or list context, then it creates and returns an object 852If called in scalar or list context, then it creates and returns an object
766that automatically removes the callback again when it is destroyed. See 853that automatically removes the callback again when it is destroyed. See
767L<Coro::BDB> for a case where this is useful. 854L<Coro::BDB> for a case where this is useful.
768 855
771If there are any code references in this array (you can C<push> to it 858If there are any code references in this array (you can C<push> to it
772before or after loading AnyEvent), then they will called directly after 859before or after loading AnyEvent), then they will called directly after
773the event loop has been chosen. 860the event loop has been chosen.
774 861
775You should check C<$AnyEvent::MODEL> before adding to this array, though: 862You should check C<$AnyEvent::MODEL> before adding to this array, though:
776if it contains a true value then the event loop has already been detected, 863if it is defined then the event loop has already been detected, and the
777and the array will be ignored. 864array will be ignored.
778 865
779Best use C<AnyEvent::post_detect { BLOCK }> instead. 866Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
867it,as it takes care of these details.
868
869This variable is mainly useful for modules that can do something useful
870when AnyEvent is used and thus want to know when it is initialised, but do
871not need to even load it by default. This array provides the means to hook
872into AnyEvent passively, without loading it.
780 873
781=back 874=back
782 875
783=head1 WHAT TO DO IN A MODULE 876=head1 WHAT TO DO IN A MODULE
784 877
839 932
840 933
841=head1 OTHER MODULES 934=head1 OTHER MODULES
842 935
843The following is a non-exhaustive list of additional modules that use 936The following is a non-exhaustive list of additional modules that use
844AnyEvent and can therefore be mixed easily with other AnyEvent modules 937AnyEvent as a client and can therefore be mixed easily with other AnyEvent
845in the same program. Some of the modules come with AnyEvent, some are 938modules and other event loops in the same program. Some of the modules
846available via CPAN. 939come with AnyEvent, most are available via CPAN.
847 940
848=over 4 941=over 4
849 942
850=item L<AnyEvent::Util> 943=item L<AnyEvent::Util>
851 944
860 953
861=item L<AnyEvent::Handle> 954=item L<AnyEvent::Handle>
862 955
863Provide read and write buffers, manages watchers for reads and writes, 956Provide read and write buffers, manages watchers for reads and writes,
864supports raw and formatted I/O, I/O queued and fully transparent and 957supports raw and formatted I/O, I/O queued and fully transparent and
865non-blocking SSL/TLS. 958non-blocking SSL/TLS (via L<AnyEvent::TLS>.
866 959
867=item L<AnyEvent::DNS> 960=item L<AnyEvent::DNS>
868 961
869Provides rich asynchronous DNS resolver capabilities. 962Provides rich asynchronous DNS resolver capabilities.
870 963
898 991
899=item L<AnyEvent::GPSD> 992=item L<AnyEvent::GPSD>
900 993
901A non-blocking interface to gpsd, a daemon delivering GPS information. 994A non-blocking interface to gpsd, a daemon delivering GPS information.
902 995
996=item L<AnyEvent::IRC>
997
998AnyEvent based IRC client module family (replacing the older Net::IRC3).
999
1000=item L<AnyEvent::XMPP>
1001
1002AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1003Net::XMPP2>.
1004
903=item L<AnyEvent::IGS> 1005=item L<AnyEvent::IGS>
904 1006
905A non-blocking interface to the Internet Go Server protocol (used by 1007A non-blocking interface to the Internet Go Server protocol (used by
906L<App::IGS>). 1008L<App::IGS>).
907 1009
908=item L<AnyEvent::IRC>
909
910AnyEvent based IRC client module family (replacing the older Net::IRC3).
911
912=item L<Net::XMPP2>
913
914AnyEvent based XMPP (Jabber protocol) module family.
915
916=item L<Net::FCP> 1010=item L<Net::FCP>
917 1011
918AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1012AnyEvent-based implementation of the Freenet Client Protocol, birthplace
919of AnyEvent. 1013of AnyEvent.
920 1014
924 1018
925=item L<Coro> 1019=item L<Coro>
926 1020
927Has special support for AnyEvent via L<Coro::AnyEvent>. 1021Has special support for AnyEvent via L<Coro::AnyEvent>.
928 1022
929=item L<IO::Lambda>
930
931The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
932
933=back 1023=back
934 1024
935=cut 1025=cut
936 1026
937package AnyEvent; 1027package AnyEvent;
938 1028
939no warnings; 1029no warnings;
940use strict qw(vars subs); 1030use strict qw(vars subs);
941 1031
942use Carp; 1032use Carp ();
943 1033
944our $VERSION = 4.412; 1034our $VERSION = 4.83;
945our $MODEL; 1035our $MODEL;
946 1036
947our $AUTOLOAD; 1037our $AUTOLOAD;
948our @ISA; 1038our @ISA;
949 1039
975 [Event:: => AnyEvent::Impl::Event::], 1065 [Event:: => AnyEvent::Impl::Event::],
976 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1066 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
977 # everything below here will not be autoprobed 1067 # everything below here will not be autoprobed
978 # as the pureperl backend should work everywhere 1068 # as the pureperl backend should work everywhere
979 # and is usually faster 1069 # and is usually faster
980 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
981 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1070 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
982 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1071 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1072 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
983 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1073 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
984 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1074 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
985 [Wx:: => AnyEvent::Impl::POE::], 1075 [Wx:: => AnyEvent::Impl::POE::],
986 [Prima:: => AnyEvent::Impl::POE::], 1076 [Prima:: => AnyEvent::Impl::POE::],
987 # IO::Async is just too broken - we would need workaorunds for its 1077 # IO::Async is just too broken - we would need workarounds for its
988 # byzantine signal and broken child handling, among others. 1078 # byzantine signal and broken child handling, among others.
989 # IO::Async is rather hard to detect, as it doesn't have any 1079 # IO::Async is rather hard to detect, as it doesn't have any
990 # obvious default class. 1080 # obvious default class.
991# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program 1081# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
992# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program 1082# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1025 1115
1026 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1116 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1027 my $model = "AnyEvent::Impl::$1"; 1117 my $model = "AnyEvent::Impl::$1";
1028 if (eval "require $model") { 1118 if (eval "require $model") {
1029 $MODEL = $model; 1119 $MODEL = $model;
1030 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1120 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $verbose > 1;
1031 } else { 1121 } else {
1032 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1122 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $verbose;
1033 } 1123 }
1034 } 1124 }
1035 1125
1036 # check for already loaded models 1126 # check for already loaded models
1037 unless ($MODEL) { 1127 unless ($MODEL) {
1079 1169
1080sub AUTOLOAD { 1170sub AUTOLOAD {
1081 (my $func = $AUTOLOAD) =~ s/.*://; 1171 (my $func = $AUTOLOAD) =~ s/.*://;
1082 1172
1083 $method{$func} 1173 $method{$func}
1084 or croak "$func: not a valid method for AnyEvent objects"; 1174 or Carp::croak "$func: not a valid method for AnyEvent objects";
1085 1175
1086 detect unless $MODEL; 1176 detect unless $MODEL;
1087 1177
1088 my $class = shift; 1178 my $class = shift;
1089 $class->$func (@_); 1179 $class->$func (@_);
1094# allow only one watcher per fd, so we dup it to get a different one). 1184# allow only one watcher per fd, so we dup it to get a different one).
1095sub _dupfh($$;$$) { 1185sub _dupfh($$;$$) {
1096 my ($poll, $fh, $r, $w) = @_; 1186 my ($poll, $fh, $r, $w) = @_;
1097 1187
1098 # cygwin requires the fh mode to be matching, unix doesn't 1188 # cygwin requires the fh mode to be matching, unix doesn't
1099 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1189 my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");
1100 : $poll eq "w" ? ($w, ">")
1101 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1102 1190
1103 open my $fh2, "$mode&" . fileno $fh 1191 open my $fh2, "$mode&", $fh
1104 or die "cannot dup() filehandle: $!,"; 1192 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1105 1193
1106 # we assume CLOEXEC is already set by perl in all important cases 1194 # we assume CLOEXEC is already set by perl in all important cases
1107 1195
1108 ($fh2, $rw) 1196 ($fh2, $rw)
1109} 1197}
1284 1372
1285use overload 1373use overload
1286 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1374 '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1287 fallback => 1; 1375 fallback => 1;
1288 1376
1377our $WAITING;
1378
1289sub _send { 1379sub _send {
1290 # nop 1380 # nop
1291} 1381}
1292 1382
1293sub send { 1383sub send {
1305sub ready { 1395sub ready {
1306 $_[0]{_ae_sent} 1396 $_[0]{_ae_sent}
1307} 1397}
1308 1398
1309sub _wait { 1399sub _wait {
1400 $WAITING
1401 and !$_[0]{_ae_sent}
1402 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1403
1404 local $WAITING = 1;
1310 AnyEvent->one_event while !$_[0]{_ae_sent}; 1405 AnyEvent->one_event while !$_[0]{_ae_sent};
1311} 1406}
1312 1407
1313sub recv { 1408sub recv {
1314 $_[0]->_wait; 1409 $_[0]->_wait;
1441 1536
1442=item C<PERL_ANYEVENT_MAX_FORKS> 1537=item C<PERL_ANYEVENT_MAX_FORKS>
1443 1538
1444The maximum number of child processes that C<AnyEvent::Util::fork_call> 1539The maximum number of child processes that C<AnyEvent::Util::fork_call>
1445will create in parallel. 1540will create in parallel.
1541
1542=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1543
1544The default value for the C<max_outstanding> parameter for the default DNS
1545resolver - this is the maximum number of parallel DNS requests that are
1546sent to the DNS server.
1547
1548=item C<PERL_ANYEVENT_RESOLV_CONF>
1549
1550The file to use instead of F</etc/resolv.conf> (or OS-specific
1551configuration) in the default resolver. When set to the empty string, no
1552default config will be used.
1553
1554=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1555
1556When neither C<ca_file> nor C<ca_path> was specified during
1557L<AnyEvent::TLS> context creation, and either of these environment
1558variables exist, they will be used to specify CA certificate locations
1559instead of a system-dependent default.
1446 1560
1447=back 1561=back
1448 1562
1449=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1563=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1450 1564
1695 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 1809 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1696 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 1810 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1697 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 1811 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1698 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 1812 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1699 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 1813 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1814 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
1815 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1700 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 1816 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1701 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 1817 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1702 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 1818 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1703 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 1819 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1704 1820
1733performance becomes really bad with lots of file descriptors (and few of 1849performance becomes really bad with lots of file descriptors (and few of
1734them active), of course, but this was not subject of this benchmark. 1850them active), of course, but this was not subject of this benchmark.
1735 1851
1736The C<Event> module has a relatively high setup and callback invocation 1852The C<Event> module has a relatively high setup and callback invocation
1737cost, but overall scores in on the third place. 1853cost, but overall scores in on the third place.
1854
1855C<IO::Async> performs admirably well, about on par with C<Event>, even
1856when using its pure perl backend.
1738 1857
1739C<Glib>'s memory usage is quite a bit higher, but it features a 1858C<Glib>'s memory usage is quite a bit higher, but it features a
1740faster callback invocation and overall ends up in the same class as 1859faster callback invocation and overall ends up in the same class as
1741C<Event>. However, Glib scales extremely badly, doubling the number of 1860C<Event>. However, Glib scales extremely badly, doubling the number of
1742watchers increases the processing time by more than a factor of four, 1861watchers increases the processing time by more than a factor of four,
1820it to another server. This includes deleting the old timeout and creating 1939it to another server. This includes deleting the old timeout and creating
1821a new one that moves the timeout into the future. 1940a new one that moves the timeout into the future.
1822 1941
1823=head3 Results 1942=head3 Results
1824 1943
1825 name sockets create request 1944 name sockets create request
1826 EV 20000 69.01 11.16 1945 EV 20000 69.01 11.16
1827 Perl 20000 73.32 35.87 1946 Perl 20000 73.32 35.87
1947 IOAsync 20000 157.00 98.14 epoll
1948 IOAsync 20000 159.31 616.06 poll
1828 Event 20000 212.62 257.32 1949 Event 20000 212.62 257.32
1829 Glib 20000 651.16 1896.30 1950 Glib 20000 651.16 1896.30
1830 POE 20000 349.67 12317.24 uses POE::Loop::Event 1951 POE 20000 349.67 12317.24 uses POE::Loop::Event
1831 1952
1832=head3 Discussion 1953=head3 Discussion
1833 1954
1834This benchmark I<does> measure scalability and overall performance of the 1955This benchmark I<does> measure scalability and overall performance of the
1835particular event loop. 1956particular event loop.
1837EV is again fastest. Since it is using epoll on my system, the setup time 1958EV is again fastest. Since it is using epoll on my system, the setup time
1838is relatively high, though. 1959is relatively high, though.
1839 1960
1840Perl surprisingly comes second. It is much faster than the C-based event 1961Perl surprisingly comes second. It is much faster than the C-based event
1841loops Event and Glib. 1962loops Event and Glib.
1963
1964IO::Async performs very well when using its epoll backend, and still quite
1965good compared to Glib when using its pure perl backend.
1842 1966
1843Event suffers from high setup time as well (look at its code and you will 1967Event suffers from high setup time as well (look at its code and you will
1844understand why). Callback invocation also has a high overhead compared to 1968understand why). Callback invocation also has a high overhead compared to
1845the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 1969the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1846uses select or poll in basically all documented configurations. 1970uses select or poll in basically all documented configurations.
1979 2103
1980A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2104A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1981emulation for event loops that do not support them natively. Also, some 2105emulation for event loops that do not support them natively. Also, some
1982event loops install a similar handler. 2106event loops install a similar handler.
1983 2107
1984If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will 2108Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
1985reset it to default, to avoid losing child exit statuses. 2109AnyEvent will reset it to default, to avoid losing child exit statuses.
1986 2110
1987=item SIGPIPE 2111=item SIGPIPE
1988 2112
1989A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 2113A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1990when AnyEvent gets loaded. 2114when AnyEvent gets loaded.
2063L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2187L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2064 2188
2065Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2189Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2066L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2190L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2067L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2191L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2068L<AnyEvent::Impl::POE>. 2192L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
2069 2193
2070Non-blocking file handles, sockets, TCP clients and 2194Non-blocking file handles, sockets, TCP clients and
2071servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2195servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2072 2196
2073Asynchronous DNS: L<AnyEvent::DNS>. 2197Asynchronous DNS: L<AnyEvent::DNS>.
2074 2198
2075Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2199Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2200L<Coro::Event>,
2076 2201
2077Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2202Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2203L<AnyEvent::HTTP>.
2078 2204
2079 2205
2080=head1 AUTHOR 2206=head1 AUTHOR
2081 2207
2082 Marc Lehmann <schmorp@schmorp.de> 2208 Marc Lehmann <schmorp@schmorp.de>

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines