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 1.209 by root, Wed May 13 13:36:49 2009 UTC vs.
Revision 1.309 by root, Sat Dec 26 08:59:35 2009 UTC

1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - the DBI of event loop programming
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops 5EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6and POE are various supported event loops/environments.
6 7
7=head1 SYNOPSIS 8=head1 SYNOPSIS
8 9
9 use AnyEvent; 10 use AnyEvent;
10 11
39=head1 INTRODUCTION/TUTORIAL 40=head1 INTRODUCTION/TUTORIAL
40 41
41This manpage is mainly a reference manual. If you are interested 42This manpage is mainly a reference manual. If you are interested
42in a tutorial or some gentle introduction, have a look at the 43in a tutorial or some gentle introduction, have a look at the
43L<AnyEvent::Intro> manpage. 44L<AnyEvent::Intro> manpage.
45
46=head1 SUPPORT
47
48There is a mailinglist for discussing all things AnyEvent, and an IRC
49channel, too.
50
51See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52Repository>, at L<http://anyevent.schmorp.de>, for more info.
44 53
45=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 54=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
46 55
47Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 56Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
48nowadays. So what is different about AnyEvent? 57nowadays. So what is different about AnyEvent?
172my variables are only visible after the statement in which they are 181my variables are only visible after the statement in which they are
173declared. 182declared.
174 183
175=head2 I/O WATCHERS 184=head2 I/O WATCHERS
176 185
186 $w = AnyEvent->io (
187 fh => <filehandle_or_fileno>,
188 poll => <"r" or "w">,
189 cb => <callback>,
190 );
191
177You can create an I/O watcher by calling the C<< AnyEvent->io >> method 192You can create an I/O watcher by calling the C<< AnyEvent->io >> method
178with the following mandatory key-value pairs as arguments: 193with the following mandatory key-value pairs as arguments:
179 194
180C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch 195C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
181for events (AnyEvent might or might not keep a reference to this file 196for events (AnyEvent might or might not keep a reference to this file
182handle). Note that only file handles pointing to things for which 197handle). Note that only file handles pointing to things for which
183non-blocking operation makes sense are allowed. This includes sockets, 198non-blocking operation makes sense are allowed. This includes sockets,
184most character devices, pipes, fifos and so on, but not for example files 199most character devices, pipes, fifos and so on, but not for example files
185or block devices. 200or block devices.
210 undef $w; 225 undef $w;
211 }); 226 });
212 227
213=head2 TIME WATCHERS 228=head2 TIME WATCHERS
214 229
230 $w = AnyEvent->timer (after => <seconds>, cb => <callback>);
231
232 $w = AnyEvent->timer (
233 after => <fractional_seconds>,
234 interval => <fractional_seconds>,
235 cb => <callback>,
236 );
237
215You can create a time watcher by calling the C<< AnyEvent->timer >> 238You can create a time watcher by calling the C<< AnyEvent->timer >>
216method with the following mandatory arguments: 239method with the following mandatory arguments:
217 240
218C<after> specifies after how many seconds (fractional values are 241C<after> specifies after how many seconds (fractional values are
219supported) the callback should be invoked. C<cb> is the callback to invoke 242supported) the callback should be invoked. C<cb> is the callback to invoke
340might affect timers and time-outs. 363might affect timers and time-outs.
341 364
342When this is the case, you can call this method, which will update the 365When this is the case, you can call this method, which will update the
343event loop's idea of "current time". 366event loop's idea of "current time".
344 367
368A typical example would be a script in a web server (e.g. C<mod_perl>) -
369when mod_perl executes the script, then the event loop will have the wrong
370idea about the "current time" (being potentially far in the past, when the
371script ran the last time). In that case you should arrange a call to C<<
372AnyEvent->now_update >> each time the web server process wakes up again
373(e.g. at the start of your script, or in a handler).
374
345Note that updating the time I<might> cause some events to be handled. 375Note that updating the time I<might> cause some events to be handled.
346 376
347=back 377=back
348 378
349=head2 SIGNAL WATCHERS 379=head2 SIGNAL WATCHERS
380
381 $w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
350 382
351You can watch for signals using a signal watcher, C<signal> is the signal 383You can watch for signals using a signal watcher, C<signal> is the signal
352I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl 384I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
353callback to be invoked whenever a signal occurs. 385callback to be invoked whenever a signal occurs.
354 386
360invocation, and callback invocation will be synchronous. Synchronous means 392invocation, and callback invocation will be synchronous. Synchronous means
361that it might take a while until the signal gets handled by the process, 393that it might take a while until the signal gets handled by the process,
362but it is guaranteed not to interrupt any other callbacks. 394but it is guaranteed not to interrupt any other callbacks.
363 395
364The main advantage of using these watchers is that you can share a signal 396The main advantage of using these watchers is that you can share a signal
365between multiple watchers. 397between multiple watchers, and AnyEvent will ensure that signals will not
398interrupt your program at bad times.
366 399
367This watcher might use C<%SIG>, so programs overwriting those signals 400This watcher might use C<%SIG> (depending on the event loop used),
368directly will likely not work correctly. 401so programs overwriting those signals directly will likely not work
402correctly.
369 403
370Example: exit on SIGINT 404Example: exit on SIGINT
371 405
372 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 406 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
373 407
408=head3 Restart Behaviour
409
410While restart behaviour is up to the event loop implementation, most will
411not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
412pure perl implementation).
413
414=head3 Safe/Unsafe Signals
415
416Perl signals can be either "safe" (synchronous to opcode handling) or
417"unsafe" (asynchronous) - the former might get delayed indefinitely, the
418latter might corrupt your memory.
419
420AnyEvent signal handlers are, in addition, synchronous to the event loop,
421i.e. they will not interrupt your running perl program but will only be
422called as part of the normal event handling (just like timer, I/O etc.
423callbacks, too).
424
425=head3 Signal Races, Delays and Workarounds
426
427Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
428callbacks to signals in a generic way, which is a pity, as you cannot
429do race-free signal handling in perl, requiring C libraries for
430this. AnyEvent will try to do it's best, which means in some cases,
431signals will be delayed. The maximum time a signal might be delayed is
432specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
433variable can be changed only before the first signal watcher is created,
434and should be left alone otherwise. This variable determines how often
435AnyEvent polls for signals (in case a wake-up was missed). Higher values
436will cause fewer spurious wake-ups, which is better for power and CPU
437saving.
438
439All these problems can be avoided by installing the optional
440L<Async::Interrupt> module, which works with most event loops. It will not
441work with inherently broken event loops such as L<Event> or L<Event::Lib>
442(and not with L<POE> currently, as POE does it's own workaround with
443one-second latency). For those, you just have to suffer the delays.
444
374=head2 CHILD PROCESS WATCHERS 445=head2 CHILD PROCESS WATCHERS
375 446
447 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
448
376You can also watch on a child process exit and catch its exit status. 449You can also watch on a child process exit and catch its exit status.
377 450
378The child process is specified by the C<pid> argument (if set to C<0>, it 451The child process is specified by the C<pid> argument (one some backends,
379watches for any child process exit). The watcher will triggered only when 452using C<0> watches for any child process exit, on others this will
380the child process has finished and an exit status is available, not on 453croak). The watcher will be triggered only when the child process has
381any trace events (stopped/continued). 454finished and an exit status is available, not on any trace events
455(stopped/continued).
382 456
383The callback will be called with the pid and exit status (as returned by 457The callback will be called with the pid and exit status (as returned by
384waitpid), so unlike other watcher types, you I<can> rely on child watcher 458waitpid), so unlike other watcher types, you I<can> rely on child watcher
385callback arguments. 459callback arguments.
386 460
391 465
392There is a slight catch to child watchers, however: you usually start them 466There is a slight catch to child watchers, however: you usually start them
393I<after> the child process was created, and this means the process could 467I<after> the child process was created, and this means the process could
394have exited already (and no SIGCHLD will be sent anymore). 468have exited already (and no SIGCHLD will be sent anymore).
395 469
396Not all event models handle this correctly (POE doesn't), but even for 470Not all event models handle this correctly (neither POE nor IO::Async do,
471see their AnyEvent::Impl manpages for details), but even for event models
397event models that I<do> handle this correctly, they usually need to be 472that I<do> handle this correctly, they usually need to be loaded before
398loaded before the process exits (i.e. before you fork in the first place). 473the process exits (i.e. before you fork in the first place). AnyEvent's
474pure perl event loop handles all cases correctly regardless of when you
475start the watcher.
399 476
400This means you cannot create a child watcher as the very first thing in an 477This means you cannot create a child watcher as the very first
401AnyEvent program, you I<have> to create at least one watcher before you 478thing in an AnyEvent program, you I<have> to create at least one
402C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 479watcher before you C<fork> the child (alternatively, you can call
480C<AnyEvent::detect>).
481
482As most event loops do not support waiting for child events, they will be
483emulated by AnyEvent in most cases, in which the latency and race problems
484mentioned in the description of signal watchers apply.
403 485
404Example: fork a process and wait for it 486Example: fork a process and wait for it
405 487
406 my $done = AnyEvent->condvar; 488 my $done = AnyEvent->condvar;
407 489
419 # do something else, then wait for process exit 501 # do something else, then wait for process exit
420 $done->recv; 502 $done->recv;
421 503
422=head2 IDLE WATCHERS 504=head2 IDLE WATCHERS
423 505
424Sometimes there is a need to do something, but it is not so important 506 $w = AnyEvent->idle (cb => <callback>);
425to do it instantly, but only when there is nothing better to do. This
426"nothing better to do" is usually defined to be "no other events need
427attention by the event loop".
428 507
429Idle watchers ideally get invoked when the event loop has nothing 508Repeatedly invoke the callback after the process becomes idle, until
430better to do, just before it would block the process to wait for new 509either the watcher is destroyed or new events have been detected.
431events. Instead of blocking, the idle watcher is invoked.
432 510
433Most event loops unfortunately do not really support idle watchers (only 511Idle watchers are useful when there is a need to do something, but it
512is not so important (or wise) to do it instantly. The callback will be
513invoked only when there is "nothing better to do", which is usually
514defined as "all outstanding events have been handled and no new events
515have been detected". That means that idle watchers ideally get invoked
516when the event loop has just polled for new events but none have been
517detected. Instead of blocking to wait for more events, the idle watchers
518will be invoked.
519
520Unfortunately, most event loops do not really support idle watchers (only
434EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent 521EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
435will simply call the callback "from time to time". 522will simply call the callback "from time to time".
436 523
437Example: read lines from STDIN, but only process them when the 524Example: read lines from STDIN, but only process them when the
438program is otherwise idle: 525program is otherwise idle:
454 }); 541 });
455 }); 542 });
456 543
457=head2 CONDITION VARIABLES 544=head2 CONDITION VARIABLES
458 545
546 $cv = AnyEvent->condvar;
547
548 $cv->send (<list>);
549 my @res = $cv->recv;
550
459If you are familiar with some event loops you will know that all of them 551If you are familiar with some event loops you will know that all of them
460require you to run some blocking "loop", "run" or similar function that 552require you to run some blocking "loop", "run" or similar function that
461will actively watch for new events and call your callbacks. 553will actively watch for new events and call your callbacks.
462 554
463AnyEvent is different, it expects somebody else to run the event loop and 555AnyEvent is slightly different: it expects somebody else to run the event
464will only block when necessary (usually when told by the user). 556loop and will only block when necessary (usually when told by the user).
465 557
466The instrument to do that is called a "condition variable", so called 558The instrument to do that is called a "condition variable", so called
467because they represent a condition that must become true. 559because they represent a condition that must become true.
468 560
561Now is probably a good time to look at the examples further below.
562
469Condition variables can be created by calling the C<< AnyEvent->condvar 563Condition variables can be created by calling the C<< AnyEvent->condvar
470>> method, usually without arguments. The only argument pair allowed is 564>> method, usually without arguments. The only argument pair allowed is
471
472C<cb>, which specifies a callback to be called when the condition variable 565C<cb>, which specifies a callback to be called when the condition variable
473becomes true, with the condition variable as the first argument (but not 566becomes true, with the condition variable as the first argument (but not
474the results). 567the results).
475 568
476After creation, the condition variable is "false" until it becomes "true" 569After creation, the condition variable is "false" until it becomes "true"
481Condition variables are similar to callbacks, except that you can 574Condition variables are similar to callbacks, except that you can
482optionally wait for them. They can also be called merge points - points 575optionally wait for them. They can also be called merge points - points
483in time where multiple outstanding events have been processed. And yet 576in time where multiple outstanding events have been processed. And yet
484another way to call them is transactions - each condition variable can be 577another way to call them is transactions - each condition variable can be
485used to represent a transaction, which finishes at some point and delivers 578used to represent a transaction, which finishes at some point and delivers
486a result. 579a result. And yet some people know them as "futures" - a promise to
580compute/deliver something that you can wait for.
487 581
488Condition variables are very useful to signal that something has finished, 582Condition variables are very useful to signal that something has finished,
489for example, if you write a module that does asynchronous http requests, 583for example, if you write a module that does asynchronous http requests,
490then a condition variable would be the ideal candidate to signal the 584then a condition variable would be the ideal candidate to signal the
491availability of results. The user can either act when the callback is 585availability of results. The user can either act when the callback is
525 after => 1, 619 after => 1,
526 cb => sub { $result_ready->send }, 620 cb => sub { $result_ready->send },
527 ); 621 );
528 622
529 # this "blocks" (while handling events) till the callback 623 # this "blocks" (while handling events) till the callback
530 # calls send 624 # calls ->send
531 $result_ready->recv; 625 $result_ready->recv;
532 626
533Example: wait for a timer, but take advantage of the fact that 627Example: wait for a timer, but take advantage of the fact that condition
534condition variables are also code references. 628variables are also callable directly.
535 629
536 my $done = AnyEvent->condvar; 630 my $done = AnyEvent->condvar;
537 my $delay = AnyEvent->timer (after => 5, cb => $done); 631 my $delay = AnyEvent->timer (after => 5, cb => $done);
538 $done->recv; 632 $done->recv;
539 633
545 639
546 ... 640 ...
547 641
548 my @info = $couchdb->info->recv; 642 my @info = $couchdb->info->recv;
549 643
550And this is how you would just ste a callback to be called whenever the 644And this is how you would just set a callback to be called whenever the
551results are available: 645results are available:
552 646
553 $couchdb->info->cb (sub { 647 $couchdb->info->cb (sub {
554 my @info = $_[0]->recv; 648 my @info = $_[0]->recv;
555 }); 649 });
573immediately from within send. 667immediately from within send.
574 668
575Any arguments passed to the C<send> call will be returned by all 669Any arguments passed to the C<send> call will be returned by all
576future C<< ->recv >> calls. 670future C<< ->recv >> calls.
577 671
578Condition variables are overloaded so one can call them directly 672Condition variables are overloaded so one can call them directly (as if
579(as a code reference). Calling them directly is the same as calling 673they were a code reference). Calling them directly is the same as calling
580C<send>. Note, however, that many C-based event loops do not handle 674C<send>.
581overloading, so as tempting as it may be, passing a condition variable
582instead of a callback does not work. Both the pure perl and EV loops
583support overloading, however, as well as all functions that use perl to
584invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
585example).
586 675
587=item $cv->croak ($error) 676=item $cv->croak ($error)
588 677
589Similar to send, but causes all call's to C<< ->recv >> to invoke 678Similar to send, but causes all call's to C<< ->recv >> to invoke
590C<Carp::croak> with the given error message/object/scalar. 679C<Carp::croak> with the given error message/object/scalar.
591 680
592This can be used to signal any errors to the condition variable 681This can be used to signal any errors to the condition variable
593user/consumer. 682user/consumer. Doing it this way instead of calling C<croak> directly
683delays the error detetcion, but has the overwhelmign advantage that it
684diagnoses the error at the place where the result is expected, and not
685deep in some event clalback without connection to the actual code causing
686the problem.
594 687
595=item $cv->begin ([group callback]) 688=item $cv->begin ([group callback])
596 689
597=item $cv->end 690=item $cv->end
598
599These two methods are EXPERIMENTAL and MIGHT CHANGE.
600 691
601These two methods can be used to combine many transactions/events into 692These two methods can be used to combine many transactions/events into
602one. For example, a function that pings many hosts in parallel might want 693one. For example, a function that pings many hosts in parallel might want
603to use a condition variable for the whole process. 694to use a condition variable for the whole process.
604 695
605Every call to C<< ->begin >> will increment a counter, and every call to 696Every call to C<< ->begin >> will increment a counter, and every call to
606C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 697C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
607>>, the (last) callback passed to C<begin> will be executed. That callback 698>>, the (last) callback passed to C<begin> will be executed, passing the
608is I<supposed> to call C<< ->send >>, but that is not required. If no 699condvar as first argument. That callback is I<supposed> to call C<< ->send
609callback was set, C<send> will be called without any arguments. 700>>, but that is not required. If no group callback was set, C<send> will
701be called without any arguments.
610 702
611Let's clarify this with the ping example: 703You can think of C<< $cv->send >> giving you an OR condition (one call
704sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
705condition (all C<begin> calls must be C<end>'ed before the condvar sends).
706
707Let's start with a simple example: you have two I/O watchers (for example,
708STDOUT and STDERR for a program), and you want to wait for both streams to
709close before activating a condvar:
612 710
613 my $cv = AnyEvent->condvar; 711 my $cv = AnyEvent->condvar;
614 712
713 $cv->begin; # first watcher
714 my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
715 defined sysread $fh1, my $buf, 4096
716 or $cv->end;
717 });
718
719 $cv->begin; # second watcher
720 my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
721 defined sysread $fh2, my $buf, 4096
722 or $cv->end;
723 });
724
725 $cv->recv;
726
727This works because for every event source (EOF on file handle), there is
728one call to C<begin>, so the condvar waits for all calls to C<end> before
729sending.
730
731The ping example mentioned above is slightly more complicated, as the
732there are results to be passwd back, and the number of tasks that are
733begung can potentially be zero:
734
735 my $cv = AnyEvent->condvar;
736
615 my %result; 737 my %result;
616 $cv->begin (sub { $cv->send (\%result) }); 738 $cv->begin (sub { shift->send (\%result) });
617 739
618 for my $host (@list_of_hosts) { 740 for my $host (@list_of_hosts) {
619 $cv->begin; 741 $cv->begin;
620 ping_host_then_call_callback $host, sub { 742 ping_host_then_call_callback $host, sub {
621 $result{$host} = ...; 743 $result{$host} = ...;
636loop, which serves two important purposes: first, it sets the callback 758loop, which serves two important purposes: first, it sets the callback
637to be called once the counter reaches C<0>, and second, it ensures that 759to be called once the counter reaches C<0>, and second, it ensures that
638C<send> is called even when C<no> hosts are being pinged (the loop 760C<send> is called even when C<no> hosts are being pinged (the loop
639doesn't execute once). 761doesn't execute once).
640 762
641This is the general pattern when you "fan out" into multiple subrequests: 763This is the general pattern when you "fan out" into multiple (but
642use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 764potentially none) subrequests: use an outer C<begin>/C<end> pair to set
643is called at least once, and then, for each subrequest you start, call 765the callback and ensure C<end> is called at least once, and then, for each
644C<begin> and for each subrequest you finish, call C<end>. 766subrequest you start, call C<begin> and for each subrequest you finish,
767call C<end>.
645 768
646=back 769=back
647 770
648=head3 METHODS FOR CONSUMERS 771=head3 METHODS FOR CONSUMERS
649 772
665function will call C<croak>. 788function will call C<croak>.
666 789
667In list context, all parameters passed to C<send> will be returned, 790In list context, all parameters passed to C<send> will be returned,
668in scalar context only the first one will be returned. 791in scalar context only the first one will be returned.
669 792
793Note that doing a blocking wait in a callback is not supported by any
794event loop, that is, recursive invocation of a blocking C<< ->recv
795>> is not allowed, and the C<recv> call will C<croak> if such a
796condition is detected. This condition can be slightly loosened by using
797L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
798any thread that doesn't run the event loop itself.
799
670Not all event models support a blocking wait - some die in that case 800Not all event models support a blocking wait - some die in that case
671(programs might want to do that to stay interactive), so I<if you are 801(programs might want to do that to stay interactive), so I<if you are
672using this from a module, never require a blocking wait>, but let the 802using this from a module, never require a blocking wait>. Instead, let the
673caller decide whether the call will block or not (for example, by coupling 803caller decide whether the call will block or not (for example, by coupling
674condition variables with some kind of request results and supporting 804condition variables with some kind of request results and supporting
675callbacks so the caller knows that getting the result will not block, 805callbacks so the caller knows that getting the result will not block,
676while still supporting blocking waits if the caller so desires). 806while still supporting blocking waits if the caller so desires).
677 807
678Another reason I<never> to C<< ->recv >> in a module is that you cannot
679sensibly have two C<< ->recv >>'s in parallel, as that would require
680multiple interpreters or coroutines/threads, none of which C<AnyEvent>
681can supply.
682
683The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
684fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
685versions and also integrates coroutines into AnyEvent, making blocking
686C<< ->recv >> calls perfectly safe as long as they are done from another
687coroutine (one that doesn't run the event loop).
688
689You can ensure that C<< -recv >> never blocks by setting a callback and 808You can ensure that C<< -recv >> never blocks by setting a callback and
690only calling C<< ->recv >> from within that callback (or at a later 809only calling C<< ->recv >> from within that callback (or at a later
691time). This will work even when the event loop does not support blocking 810time). This will work even when the event loop does not support blocking
692waits otherwise. 811waits otherwise.
693 812
699=item $cb = $cv->cb ($cb->($cv)) 818=item $cb = $cv->cb ($cb->($cv))
700 819
701This is a mutator function that returns the callback set and optionally 820This is a mutator function that returns the callback set and optionally
702replaces it before doing so. 821replaces it before doing so.
703 822
704The callback will be called when the condition becomes "true", i.e. when 823The callback will be called when the condition becomes (or already was)
705C<send> or C<croak> are called, with the only argument being the condition 824"true", i.e. when C<send> or C<croak> are called (or were called), with
706variable itself. Calling C<recv> inside the callback or at any later time 825the only argument being the condition variable itself. Calling C<recv>
707is guaranteed not to block. 826inside the callback or at any later time is guaranteed not to block.
708 827
709=back 828=back
710 829
830=head1 SUPPORTED EVENT LOOPS/BACKENDS
831
832The available backend classes are (every class has its own manpage):
833
834=over 4
835
836=item Backends that are autoprobed when no other event loop can be found.
837
838EV is the preferred backend when no other event loop seems to be in
839use. If EV is not installed, then AnyEvent will fall back to its own
840pure-perl implementation, which is available everywhere as it comes with
841AnyEvent itself.
842
843 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
844 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
845
846=item Backends that are transparently being picked up when they are used.
847
848These will be used when they are currently loaded when the first watcher
849is created, in which case it is assumed that the application is using
850them. This means that AnyEvent will automatically pick the right backend
851when the main program loads an event module before anything starts to
852create watchers. Nothing special needs to be done by the main program.
853
854 AnyEvent::Impl::Event based on Event, very stable, few glitches.
855 AnyEvent::Impl::Glib based on Glib, slow but very stable.
856 AnyEvent::Impl::Tk based on Tk, very broken.
857 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
858 AnyEvent::Impl::POE based on POE, very slow, some limitations.
859 AnyEvent::Impl::Irssi used when running within irssi.
860
861=item Backends with special needs.
862
863Qt requires the Qt::Application to be instantiated first, but will
864otherwise be picked up automatically. As long as the main program
865instantiates the application before any AnyEvent watchers are created,
866everything should just work.
867
868 AnyEvent::Impl::Qt based on Qt.
869
870Support for IO::Async can only be partial, as it is too broken and
871architecturally limited to even support the AnyEvent API. It also
872is the only event loop that needs the loop to be set explicitly, so
873it can only be used by a main program knowing about AnyEvent. See
874L<AnyEvent::Impl::Async> for the gory details.
875
876 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
877
878=item Event loops that are indirectly supported via other backends.
879
880Some event loops can be supported via other modules:
881
882There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
883
884B<WxWidgets> has no support for watching file handles. However, you can
885use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
886polls 20 times per second, which was considered to be too horrible to even
887consider for AnyEvent.
888
889B<Prima> is not supported as nobody seems to be using it, but it has a POE
890backend, so it can be supported through POE.
891
892AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
893load L<POE> when detecting them, in the hope that POE will pick them up,
894in which case everything will be automatic.
895
896=back
897
711=head1 GLOBAL VARIABLES AND FUNCTIONS 898=head1 GLOBAL VARIABLES AND FUNCTIONS
712 899
900These are not normally required to use AnyEvent, but can be useful to
901write AnyEvent extension modules.
902
713=over 4 903=over 4
714 904
715=item $AnyEvent::MODEL 905=item $AnyEvent::MODEL
716 906
717Contains C<undef> until the first watcher is being created. Then it 907Contains C<undef> until the first watcher is being created, before the
908backend has been autodetected.
909
718contains the event model that is being used, which is the name of the 910Afterwards it contains the event model that is being used, which is the
719Perl class implementing the model. This class is usually one of the 911name of the Perl class implementing the model. This class is usually one
720C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 912of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
721AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 913case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
722 914will be C<urxvt::anyevent>).
723The known classes so far are:
724
725 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
726 AnyEvent::Impl::Event based on Event, second best choice.
727 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
728 AnyEvent::Impl::Glib based on Glib, third-best choice.
729 AnyEvent::Impl::Tk based on Tk, very bad choice.
730 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
731 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
732 AnyEvent::Impl::POE based on POE, not generic enough for full support.
733
734There is no support for WxWidgets, as WxWidgets has no support for
735watching file handles. However, you can use WxWidgets through the
736POE Adaptor, as POE has a Wx backend that simply polls 20 times per
737second, which was considered to be too horrible to even consider for
738AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
739it's adaptor.
740
741AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
742autodetecting them.
743 915
744=item AnyEvent::detect 916=item AnyEvent::detect
745 917
746Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 918Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
747if necessary. You should only call this function right before you would 919if necessary. You should only call this function right before you would
748have created an AnyEvent watcher anyway, that is, as late as possible at 920have created an AnyEvent watcher anyway, that is, as late as possible at
749runtime. 921runtime, and not e.g. while initialising of your module.
922
923If you need to do some initialisation before AnyEvent watchers are
924created, use C<post_detect>.
750 925
751=item $guard = AnyEvent::post_detect { BLOCK } 926=item $guard = AnyEvent::post_detect { BLOCK }
752 927
753Arranges for the code block to be executed as soon as the event model is 928Arranges for the code block to be executed as soon as the event model is
754autodetected (or immediately if this has already happened). 929autodetected (or immediately if this has already happened).
755 930
931The block will be executed I<after> the actual backend has been detected
932(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
933created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
934other initialisations - see the sources of L<AnyEvent::Strict> or
935L<AnyEvent::AIO> to see how this is used.
936
937The most common usage is to create some global watchers, without forcing
938event module detection too early, for example, L<AnyEvent::AIO> creates
939and installs the global L<IO::AIO> watcher in a C<post_detect> block to
940avoid autodetecting the event module at load time.
941
756If called in scalar or list context, then it creates and returns an object 942If called in scalar or list context, then it creates and returns an object
757that automatically removes the callback again when it is destroyed. See 943that automatically removes the callback again when it is destroyed (or
944C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
758L<Coro::BDB> for a case where this is useful. 945a case where this is useful.
946
947Example: Create a watcher for the IO::AIO module and store it in
948C<$WATCHER>. Only do so after the event loop is initialised, though.
949
950 our WATCHER;
951
952 my $guard = AnyEvent::post_detect {
953 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
954 };
955
956 # the ||= is important in case post_detect immediately runs the block,
957 # as to not clobber the newly-created watcher. assigning both watcher and
958 # post_detect guard to the same variable has the advantage of users being
959 # able to just C<undef $WATCHER> if the watcher causes them grief.
960
961 $WATCHER ||= $guard;
759 962
760=item @AnyEvent::post_detect 963=item @AnyEvent::post_detect
761 964
762If there are any code references in this array (you can C<push> to it 965If there are any code references in this array (you can C<push> to it
763before or after loading AnyEvent), then they will called directly after 966before or after loading AnyEvent), then they will called directly after
764the event loop has been chosen. 967the event loop has been chosen.
765 968
766You should check C<$AnyEvent::MODEL> before adding to this array, though: 969You should check C<$AnyEvent::MODEL> before adding to this array, though:
767if it contains a true value then the event loop has already been detected, 970if it is defined then the event loop has already been detected, and the
768and the array will be ignored. 971array will be ignored.
769 972
770Best use C<AnyEvent::post_detect { BLOCK }> instead. 973Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
974it, as it takes care of these details.
975
976This variable is mainly useful for modules that can do something useful
977when AnyEvent is used and thus want to know when it is initialised, but do
978not need to even load it by default. This array provides the means to hook
979into AnyEvent passively, without loading it.
980
981Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
982together, you could put this into Coro (this is the actual code used by
983Coro to accomplish this):
984
985 if (defined $AnyEvent::MODEL) {
986 # AnyEvent already initialised, so load Coro::AnyEvent
987 require Coro::AnyEvent;
988 } else {
989 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
990 # as soon as it is
991 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
992 }
771 993
772=back 994=back
773 995
774=head1 WHAT TO DO IN A MODULE 996=head1 WHAT TO DO IN A MODULE
775 997
830 1052
831 1053
832=head1 OTHER MODULES 1054=head1 OTHER MODULES
833 1055
834The following is a non-exhaustive list of additional modules that use 1056The following is a non-exhaustive list of additional modules that use
835AnyEvent and can therefore be mixed easily with other AnyEvent modules 1057AnyEvent as a client and can therefore be mixed easily with other AnyEvent
836in the same program. Some of the modules come with AnyEvent, some are 1058modules and other event loops in the same program. Some of the modules
837available via CPAN. 1059come with AnyEvent, most are available via CPAN.
838 1060
839=over 4 1061=over 4
840 1062
841=item L<AnyEvent::Util> 1063=item L<AnyEvent::Util>
842 1064
851 1073
852=item L<AnyEvent::Handle> 1074=item L<AnyEvent::Handle>
853 1075
854Provide read and write buffers, manages watchers for reads and writes, 1076Provide read and write buffers, manages watchers for reads and writes,
855supports raw and formatted I/O, I/O queued and fully transparent and 1077supports raw and formatted I/O, I/O queued and fully transparent and
856non-blocking SSL/TLS. 1078non-blocking SSL/TLS (via L<AnyEvent::TLS>.
857 1079
858=item L<AnyEvent::DNS> 1080=item L<AnyEvent::DNS>
859 1081
860Provides rich asynchronous DNS resolver capabilities. 1082Provides rich asynchronous DNS resolver capabilities.
861 1083
889 1111
890=item L<AnyEvent::GPSD> 1112=item L<AnyEvent::GPSD>
891 1113
892A non-blocking interface to gpsd, a daemon delivering GPS information. 1114A non-blocking interface to gpsd, a daemon delivering GPS information.
893 1115
1116=item L<AnyEvent::IRC>
1117
1118AnyEvent based IRC client module family (replacing the older Net::IRC3).
1119
1120=item L<AnyEvent::XMPP>
1121
1122AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1123Net::XMPP2>.
1124
894=item L<AnyEvent::IGS> 1125=item L<AnyEvent::IGS>
895 1126
896A non-blocking interface to the Internet Go Server protocol (used by 1127A non-blocking interface to the Internet Go Server protocol (used by
897L<App::IGS>). 1128L<App::IGS>).
898 1129
899=item L<AnyEvent::IRC>
900
901AnyEvent based IRC client module family (replacing the older Net::IRC3).
902
903=item L<Net::XMPP2>
904
905AnyEvent based XMPP (Jabber protocol) module family.
906
907=item L<Net::FCP> 1130=item L<Net::FCP>
908 1131
909AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1132AnyEvent-based implementation of the Freenet Client Protocol, birthplace
910of AnyEvent. 1133of AnyEvent.
911 1134
915 1138
916=item L<Coro> 1139=item L<Coro>
917 1140
918Has special support for AnyEvent via L<Coro::AnyEvent>. 1141Has special support for AnyEvent via L<Coro::AnyEvent>.
919 1142
920=item L<IO::Lambda>
921
922The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
923
924=back 1143=back
925 1144
926=cut 1145=cut
927 1146
928package AnyEvent; 1147package AnyEvent;
929 1148
930no warnings; 1149# basically a tuned-down version of common::sense
931use strict qw(vars subs); 1150sub common_sense {
1151 # from common:.sense 1.0
1152 ${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
1153 # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1154 $^H |= 0x00000600;
1155}
932 1156
1157BEGIN { AnyEvent::common_sense }
1158
933use Carp; 1159use Carp ();
934 1160
935our $VERSION = 4.41; 1161our $VERSION = '5.23';
936our $MODEL; 1162our $MODEL;
937 1163
938our $AUTOLOAD; 1164our $AUTOLOAD;
939our @ISA; 1165our @ISA;
940 1166
941our @REGISTRY; 1167our @REGISTRY;
942 1168
943our $WIN32; 1169our $VERBOSE;
944 1170
945BEGIN { 1171BEGIN {
946 my $win32 = ! ! ($^O =~ /mswin32/i); 1172 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
947 eval "sub WIN32(){ $win32 }"; 1173 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
948}
949 1174
1175 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1176 if ${^TAINT};
1177
950our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1178 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1179
1180}
1181
1182our $MAX_SIGNAL_LATENCY = 10;
951 1183
952our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1184our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
953 1185
954{ 1186{
955 my $idx; 1187 my $idx;
957 for reverse split /\s*,\s*/, 1189 for reverse split /\s*,\s*/,
958 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1190 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
959} 1191}
960 1192
961my @models = ( 1193my @models = (
962 [EV:: => AnyEvent::Impl::EV::], 1194 [EV:: => AnyEvent::Impl::EV:: , 1],
963 [Event:: => AnyEvent::Impl::Event::],
964 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1195 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
965 # everything below here will not be autoprobed 1196 # everything below here will not (normally) be autoprobed
966 # as the pureperl backend should work everywhere 1197 # as the pureperl backend should work everywhere
967 # and is usually faster 1198 # and is usually faster
1199 [Event:: => AnyEvent::Impl::Event::, 1],
1200 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1201 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1202 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
968 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1203 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
969 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
970 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
971 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1204 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
972 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1205 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
973 [Wx:: => AnyEvent::Impl::POE::], 1206 [Wx:: => AnyEvent::Impl::POE::],
974 [Prima:: => AnyEvent::Impl::POE::], 1207 [Prima:: => AnyEvent::Impl::POE::],
1208 # IO::Async is just too broken - we would need workarounds for its
1209 # byzantine signal and broken child handling, among others.
1210 # IO::Async is rather hard to detect, as it doesn't have any
1211 # obvious default class.
1212 [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1213 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1214 [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1215 [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
975); 1216);
976 1217
977our %method = map +($_ => 1), 1218our %method = map +($_ => 1),
978 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1219 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
979 1220
983 my ($cb) = @_; 1224 my ($cb) = @_;
984 1225
985 if ($MODEL) { 1226 if ($MODEL) {
986 $cb->(); 1227 $cb->();
987 1228
988 1 1229 undef
989 } else { 1230 } else {
990 push @post_detect, $cb; 1231 push @post_detect, $cb;
991 1232
992 defined wantarray 1233 defined wantarray
993 ? bless \$cb, "AnyEvent::Util::postdetect" 1234 ? bless \$cb, "AnyEvent::Util::postdetect"
999 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1240 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1000} 1241}
1001 1242
1002sub detect() { 1243sub detect() {
1003 unless ($MODEL) { 1244 unless ($MODEL) {
1004 no strict 'refs';
1005 local $SIG{__DIE__}; 1245 local $SIG{__DIE__};
1006 1246
1007 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1247 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1008 my $model = "AnyEvent::Impl::$1"; 1248 my $model = "AnyEvent::Impl::$1";
1009 if (eval "require $model") { 1249 if (eval "require $model") {
1010 $MODEL = $model; 1250 $MODEL = $model;
1011 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1251 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1012 } else { 1252 } else {
1013 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1253 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1014 } 1254 }
1015 } 1255 }
1016 1256
1017 # check for already loaded models 1257 # check for already loaded models
1018 unless ($MODEL) { 1258 unless ($MODEL) {
1019 for (@REGISTRY, @models) { 1259 for (@REGISTRY, @models) {
1020 my ($package, $model) = @$_; 1260 my ($package, $model) = @$_;
1021 if (${"$package\::VERSION"} > 0) { 1261 if (${"$package\::VERSION"} > 0) {
1022 if (eval "require $model") { 1262 if (eval "require $model") {
1023 $MODEL = $model; 1263 $MODEL = $model;
1024 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1264 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1025 last; 1265 last;
1026 } 1266 }
1027 } 1267 }
1028 } 1268 }
1029 1269
1030 unless ($MODEL) { 1270 unless ($MODEL) {
1031 # try to load a model 1271 # try to autoload a model
1032
1033 for (@REGISTRY, @models) { 1272 for (@REGISTRY, @models) {
1034 my ($package, $model) = @$_; 1273 my ($package, $model, $autoload) = @$_;
1274 if (
1275 $autoload
1035 if (eval "require $package" 1276 and eval "require $package"
1036 and ${"$package\::VERSION"} > 0 1277 and ${"$package\::VERSION"} > 0
1037 and eval "require $model") { 1278 and eval "require $model"
1279 ) {
1038 $MODEL = $model; 1280 $MODEL = $model;
1039 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1281 warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1040 last; 1282 last;
1041 } 1283 }
1042 } 1284 }
1043 1285
1044 $MODEL 1286 $MODEL
1060 1302
1061sub AUTOLOAD { 1303sub AUTOLOAD {
1062 (my $func = $AUTOLOAD) =~ s/.*://; 1304 (my $func = $AUTOLOAD) =~ s/.*://;
1063 1305
1064 $method{$func} 1306 $method{$func}
1065 or croak "$func: not a valid method for AnyEvent objects"; 1307 or Carp::croak "$func: not a valid method for AnyEvent objects";
1066 1308
1067 detect unless $MODEL; 1309 detect unless $MODEL;
1068 1310
1069 my $class = shift; 1311 my $class = shift;
1070 $class->$func (@_); 1312 $class->$func (@_);
1071} 1313}
1072 1314
1073# utility function to dup a filehandle. this is used by many backends 1315# utility function to dup a filehandle. this is used by many backends
1074# to support binding more than one watcher per filehandle (they usually 1316# to support binding more than one watcher per filehandle (they usually
1075# allow only one watcher per fd, so we dup it to get a different one). 1317# allow only one watcher per fd, so we dup it to get a different one).
1076sub _dupfh($$$$) { 1318sub _dupfh($$;$$) {
1077 my ($poll, $fh, $r, $w) = @_; 1319 my ($poll, $fh, $r, $w) = @_;
1078 1320
1079 # cygwin requires the fh mode to be matching, unix doesn't 1321 # cygwin requires the fh mode to be matching, unix doesn't
1080 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1322 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1081 : $poll eq "w" ? ($w, ">")
1082 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1083 1323
1084 open my $fh2, "$mode&" . fileno $fh 1324 open my $fh2, $mode, $fh
1085 or die "cannot dup() filehandle: $!,"; 1325 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1086 1326
1087 # we assume CLOEXEC is already set by perl in all important cases 1327 # we assume CLOEXEC is already set by perl in all important cases
1088 1328
1089 ($fh2, $rw) 1329 ($fh2, $rw)
1090} 1330}
1091 1331
1332=head1 SIMPLIFIED AE API
1333
1334Starting with version 5.0, AnyEvent officially supports a second, much
1335simpler, API that is designed to reduce the calling, typing and memory
1336overhead.
1337
1338See the L<AE> manpage for details.
1339
1340=cut
1341
1342package AE;
1343
1344our $VERSION = $AnyEvent::VERSION;
1345
1346sub io($$$) {
1347 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1348}
1349
1350sub timer($$$) {
1351 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1352}
1353
1354sub signal($$) {
1355 AnyEvent->signal (signal => $_[0], cb => $_[1])
1356}
1357
1358sub child($$) {
1359 AnyEvent->child (pid => $_[0], cb => $_[1])
1360}
1361
1362sub idle($) {
1363 AnyEvent->idle (cb => $_[0])
1364}
1365
1366sub cv(;&) {
1367 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1368}
1369
1370sub now() {
1371 AnyEvent->now
1372}
1373
1374sub now_update() {
1375 AnyEvent->now_update
1376}
1377
1378sub time() {
1379 AnyEvent->time
1380}
1381
1092package AnyEvent::Base; 1382package AnyEvent::Base;
1093 1383
1094# default implementations for many methods 1384# default implementations for many methods
1095 1385
1096BEGIN { 1386sub _time() {
1387 # probe for availability of Time::HiRes
1097 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1388 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1389 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1098 *_time = \&Time::HiRes::time; 1390 *_time = \&Time::HiRes::time;
1099 # if (eval "use POSIX (); (POSIX::times())... 1391 # if (eval "use POSIX (); (POSIX::times())...
1100 } else { 1392 } else {
1393 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1101 *_time = sub { time }; # epic fail 1394 *_time = sub { time }; # epic fail
1102 } 1395 }
1396
1397 &_time
1103} 1398}
1104 1399
1105sub time { _time } 1400sub time { _time }
1106sub now { _time } 1401sub now { _time }
1107sub now_update { } 1402sub now_update { }
1112 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1407 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1113} 1408}
1114 1409
1115# default implementation for ->signal 1410# default implementation for ->signal
1116 1411
1412our $HAVE_ASYNC_INTERRUPT;
1413
1414sub _have_async_interrupt() {
1415 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1416 && eval "use Async::Interrupt 1.02 (); 1")
1417 unless defined $HAVE_ASYNC_INTERRUPT;
1418
1419 $HAVE_ASYNC_INTERRUPT
1420}
1421
1117our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1422our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1423our (%SIG_ASY, %SIG_ASY_W);
1424our ($SIG_COUNT, $SIG_TW);
1118 1425
1119sub _signal_exec { 1426sub _signal_exec {
1427 $HAVE_ASYNC_INTERRUPT
1428 ? $SIGPIPE_R->drain
1120 sysread $SIGPIPE_R, my $dummy, 4; 1429 : sysread $SIGPIPE_R, (my $dummy), 9;
1121 1430
1122 while (%SIG_EV) { 1431 while (%SIG_EV) {
1123 for (keys %SIG_EV) { 1432 for (keys %SIG_EV) {
1124 delete $SIG_EV{$_}; 1433 delete $SIG_EV{$_};
1125 $_->() for values %{ $SIG_CB{$_} || {} }; 1434 $_->() for values %{ $SIG_CB{$_} || {} };
1126 } 1435 }
1127 } 1436 }
1128} 1437}
1129 1438
1439# install a dummy wakeup watcher to reduce signal catching latency
1440sub _sig_add() {
1441 unless ($SIG_COUNT++) {
1442 # try to align timer on a full-second boundary, if possible
1443 my $NOW = AE::now;
1444
1445 $SIG_TW = AE::timer
1446 $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1447 $MAX_SIGNAL_LATENCY,
1448 sub { } # just for the PERL_ASYNC_CHECK
1449 ;
1450 }
1451}
1452
1453sub _sig_del {
1454 undef $SIG_TW
1455 unless --$SIG_COUNT;
1456}
1457
1458our $_sig_name_init; $_sig_name_init = sub {
1459 eval q{ # poor man's autoloading
1460 undef $_sig_name_init;
1461
1462 if (_have_async_interrupt) {
1463 *sig2num = \&Async::Interrupt::sig2num;
1464 *sig2name = \&Async::Interrupt::sig2name;
1465 } else {
1466 require Config;
1467
1468 my %signame2num;
1469 @signame2num{ split ' ', $Config::Config{sig_name} }
1470 = split ' ', $Config::Config{sig_num};
1471
1472 my @signum2name;
1473 @signum2name[values %signame2num] = keys %signame2num;
1474
1475 *sig2num = sub($) {
1476 $_[0] > 0 ? shift : $signame2num{+shift}
1477 };
1478 *sig2name = sub ($) {
1479 $_[0] > 0 ? $signum2name[+shift] : shift
1480 };
1481 }
1482 };
1483 die if $@;
1484};
1485
1486sub sig2num ($) { &$_sig_name_init; &sig2num }
1487sub sig2name($) { &$_sig_name_init; &sig2name }
1488
1130sub signal { 1489sub signal {
1131 my (undef, %arg) = @_; 1490 eval q{ # poor man's autoloading {}
1491 # probe for availability of Async::Interrupt
1492 if (_have_async_interrupt) {
1493 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1132 1494
1133 unless ($SIGPIPE_R) { 1495 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1134 require Fcntl; 1496 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1135 1497
1136 if (AnyEvent::WIN32) {
1137 require AnyEvent::Util;
1138
1139 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1140 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1141 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1142 } else { 1498 } else {
1499 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1500
1501 require Fcntl;
1502
1503 if (AnyEvent::WIN32) {
1504 require AnyEvent::Util;
1505
1506 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1507 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1508 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1509 } else {
1143 pipe $SIGPIPE_R, $SIGPIPE_W; 1510 pipe $SIGPIPE_R, $SIGPIPE_W;
1144 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; 1511 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1145 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case 1512 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1513
1514 # not strictly required, as $^F is normally 2, but let's make sure...
1515 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1516 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1517 }
1518
1519 $SIGPIPE_R
1520 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1521
1522 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1146 } 1523 }
1147 1524
1148 $SIGPIPE_R 1525 *signal = sub {
1149 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1526 my (undef, %arg) = @_;
1150 1527
1151 # not strictly required, as $^F is normally 2, but let's make sure...
1152 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1153 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1154
1155 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1156 }
1157
1158 my $signal = uc $arg{signal} 1528 my $signal = uc $arg{signal}
1159 or Carp::croak "required option 'signal' is missing"; 1529 or Carp::croak "required option 'signal' is missing";
1160 1530
1531 if ($HAVE_ASYNC_INTERRUPT) {
1532 # async::interrupt
1533
1534 $signal = sig2num $signal;
1161 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1535 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1536
1537 $SIG_ASY{$signal} ||= new Async::Interrupt
1538 cb => sub { undef $SIG_EV{$signal} },
1539 signal => $signal,
1540 pipe => [$SIGPIPE_R->filenos],
1541 pipe_autodrain => 0,
1542 ;
1543
1544 } else {
1545 # pure perl
1546
1547 # AE::Util has been loaded in signal
1548 $signal = sig2name $signal;
1549 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1550
1162 $SIG{$signal} ||= sub { 1551 $SIG{$signal} ||= sub {
1163 local $!; 1552 local $!;
1164 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 1553 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1165 undef $SIG_EV{$signal}; 1554 undef $SIG_EV{$signal};
1555 };
1556
1557 # can't do signal processing without introducing races in pure perl,
1558 # so limit the signal latency.
1559 _sig_add;
1560 }
1561
1562 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1563 };
1564
1565 *AnyEvent::Base::signal::DESTROY = sub {
1566 my ($signal, $cb) = @{$_[0]};
1567
1568 _sig_del;
1569
1570 delete $SIG_CB{$signal}{$cb};
1571
1572 $HAVE_ASYNC_INTERRUPT
1573 ? delete $SIG_ASY{$signal}
1574 : # delete doesn't work with older perls - they then
1575 # print weird messages, or just unconditionally exit
1576 # instead of getting the default action.
1577 undef $SIG{$signal}
1578 unless keys %{ $SIG_CB{$signal} };
1579 };
1166 }; 1580 };
1167 1581 die if $@;
1168 bless [$signal, $arg{cb}], "AnyEvent::Base::signal" 1582 &signal
1169}
1170
1171sub AnyEvent::Base::signal::DESTROY {
1172 my ($signal, $cb) = @{$_[0]};
1173
1174 delete $SIG_CB{$signal}{$cb};
1175
1176 $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };
1177} 1583}
1178 1584
1179# default implementation for ->child 1585# default implementation for ->child
1180 1586
1181our %PID_CB; 1587our %PID_CB;
1182our $CHLD_W; 1588our $CHLD_W;
1183our $CHLD_DELAY_W; 1589our $CHLD_DELAY_W;
1184our $PID_IDLE;
1185our $WNOHANG; 1590our $WNOHANG;
1186 1591
1187sub _child_wait { 1592sub _emit_childstatus($$) {
1188 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1593 my (undef, $rpid, $rstatus) = @_;
1594
1595 $_->($rpid, $rstatus)
1189 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1596 for values %{ $PID_CB{$rpid} || {} },
1190 (values %{ $PID_CB{0} || {} }); 1597 values %{ $PID_CB{0} || {} };
1191 }
1192
1193 undef $PID_IDLE;
1194} 1598}
1195 1599
1196sub _sigchld { 1600sub _sigchld {
1197 # make sure we deliver these changes "synchronous" with the event loop. 1601 my $pid;
1198 $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub { 1602
1199 undef $CHLD_DELAY_W; 1603 AnyEvent->_emit_childstatus ($pid, $?)
1200 &_child_wait; 1604 while ($pid = waitpid -1, $WNOHANG) > 0;
1201 });
1202} 1605}
1203 1606
1204sub child { 1607sub child {
1205 my (undef, %arg) = @_; 1608 my (undef, %arg) = @_;
1206 1609
1207 defined (my $pid = $arg{pid} + 0) 1610 defined (my $pid = $arg{pid} + 0)
1208 or Carp::croak "required option 'pid' is missing"; 1611 or Carp::croak "required option 'pid' is missing";
1209 1612
1210 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1613 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1211 1614
1212 unless ($WNOHANG) { 1615 # WNOHANG is almost cetrainly 1 everywhere
1616 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1617 ? 1
1213 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1618 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1214 }
1215 1619
1216 unless ($CHLD_W) { 1620 unless ($CHLD_W) {
1217 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1621 $CHLD_W = AE::signal CHLD => \&_sigchld;
1218 # child could be a zombie already, so make at least one round 1622 # child could be a zombie already, so make at least one round
1219 &_sigchld; 1623 &_sigchld;
1220 } 1624 }
1221 1625
1222 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1626 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1230 1634
1231 undef $CHLD_W unless keys %PID_CB; 1635 undef $CHLD_W unless keys %PID_CB;
1232} 1636}
1233 1637
1234# idle emulation is done by simply using a timer, regardless 1638# idle emulation is done by simply using a timer, regardless
1235# of whether the proces sis idle or not, and not letting 1639# of whether the process is idle or not, and not letting
1236# the callback use more than 50% of the time. 1640# the callback use more than 50% of the time.
1237sub idle { 1641sub idle {
1238 my (undef, %arg) = @_; 1642 my (undef, %arg) = @_;
1239 1643
1240 my ($cb, $w, $rcb) = $arg{cb}; 1644 my ($cb, $w, $rcb) = $arg{cb};
1248 # never use more then 50% of the time for the idle watcher, 1652 # never use more then 50% of the time for the idle watcher,
1249 # within some limits 1653 # within some limits
1250 $w = 0.0001 if $w < 0.0001; 1654 $w = 0.0001 if $w < 0.0001;
1251 $w = 5 if $w > 5; 1655 $w = 5 if $w > 5;
1252 1656
1253 $w = AnyEvent->timer (after => $w, cb => $rcb); 1657 $w = AE::timer $w, 0, $rcb;
1254 } else { 1658 } else {
1255 # clean up... 1659 # clean up...
1256 undef $w; 1660 undef $w;
1257 undef $rcb; 1661 undef $rcb;
1258 } 1662 }
1259 }; 1663 };
1260 1664
1261 $w = AnyEvent->timer (after => 0.05, cb => $rcb); 1665 $w = AE::timer 0.05, 0, $rcb;
1262 1666
1263 bless \\$cb, "AnyEvent::Base::idle" 1667 bless \\$cb, "AnyEvent::Base::idle"
1264} 1668}
1265 1669
1266sub AnyEvent::Base::idle::DESTROY { 1670sub AnyEvent::Base::idle::DESTROY {
1271 1675
1272our @ISA = AnyEvent::CondVar::Base::; 1676our @ISA = AnyEvent::CondVar::Base::;
1273 1677
1274package AnyEvent::CondVar::Base; 1678package AnyEvent::CondVar::Base;
1275 1679
1276use overload 1680#use overload
1277 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1681# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1278 fallback => 1; 1682# fallback => 1;
1683
1684# save 300+ kilobytes by dirtily hardcoding overloading
1685${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
1686*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
1687*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
1688${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1689
1690our $WAITING;
1279 1691
1280sub _send { 1692sub _send {
1281 # nop 1693 # nop
1282} 1694}
1283 1695
1296sub ready { 1708sub ready {
1297 $_[0]{_ae_sent} 1709 $_[0]{_ae_sent}
1298} 1710}
1299 1711
1300sub _wait { 1712sub _wait {
1713 $WAITING
1714 and !$_[0]{_ae_sent}
1715 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1716
1717 local $WAITING = 1;
1301 AnyEvent->one_event while !$_[0]{_ae_sent}; 1718 AnyEvent->one_event while !$_[0]{_ae_sent};
1302} 1719}
1303 1720
1304sub recv { 1721sub recv {
1305 $_[0]->_wait; 1722 $_[0]->_wait;
1307 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1724 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1308 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1725 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1309} 1726}
1310 1727
1311sub cb { 1728sub cb {
1312 $_[0]{_ae_cb} = $_[1] if @_ > 1; 1729 my $cv = shift;
1730
1731 @_
1732 and $cv->{_ae_cb} = shift
1733 and $cv->{_ae_sent}
1734 and (delete $cv->{_ae_cb})->($cv);
1735
1313 $_[0]{_ae_cb} 1736 $cv->{_ae_cb}
1314} 1737}
1315 1738
1316sub begin { 1739sub begin {
1317 ++$_[0]{_ae_counter}; 1740 ++$_[0]{_ae_counter};
1318 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 1741 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1346so on. 1769so on.
1347 1770
1348=head1 ENVIRONMENT VARIABLES 1771=head1 ENVIRONMENT VARIABLES
1349 1772
1350The following environment variables are used by this module or its 1773The following environment variables are used by this module or its
1351submodules: 1774submodules.
1775
1776Note that AnyEvent will remove I<all> environment variables starting with
1777C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
1778enabled.
1352 1779
1353=over 4 1780=over 4
1354 1781
1355=item C<PERL_ANYEVENT_VERBOSE> 1782=item C<PERL_ANYEVENT_VERBOSE>
1356 1783
1363C<PERL_ANYEVENT_MODEL>. 1790C<PERL_ANYEVENT_MODEL>.
1364 1791
1365When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1792When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1366model it chooses. 1793model it chooses.
1367 1794
1795When set to C<8> or higher, then AnyEvent will report extra information on
1796which optional modules it loads and how it implements certain features.
1797
1368=item C<PERL_ANYEVENT_STRICT> 1798=item C<PERL_ANYEVENT_STRICT>
1369 1799
1370AnyEvent does not do much argument checking by default, as thorough 1800AnyEvent does not do much argument checking by default, as thorough
1371argument checking is very costly. Setting this variable to a true value 1801argument checking is very costly. Setting this variable to a true value
1372will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1802will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1373check the arguments passed to most method calls. If it finds any problems 1803check the arguments passed to most method calls. If it finds any problems,
1374it will croak. 1804it will croak.
1375 1805
1376In other words, enables "strict" mode. 1806In other words, enables "strict" mode.
1377 1807
1378Unlike C<use strict>, it is definitely recommended ot keep it off in 1808Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1379production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1809>>, it is definitely recommended to keep it off in production. Keeping
1380developing programs can be very useful, however. 1810C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1811can be very useful, however.
1381 1812
1382=item C<PERL_ANYEVENT_MODEL> 1813=item C<PERL_ANYEVENT_MODEL>
1383 1814
1384This can be used to specify the event model to be used by AnyEvent, before 1815This can be used to specify the event model to be used by AnyEvent, before
1385auto detection and -probing kicks in. It must be a string consisting 1816auto detection and -probing kicks in. It must be a string consisting
1428 1859
1429=item C<PERL_ANYEVENT_MAX_FORKS> 1860=item C<PERL_ANYEVENT_MAX_FORKS>
1430 1861
1431The maximum number of child processes that C<AnyEvent::Util::fork_call> 1862The maximum number of child processes that C<AnyEvent::Util::fork_call>
1432will create in parallel. 1863will create in parallel.
1864
1865=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1866
1867The default value for the C<max_outstanding> parameter for the default DNS
1868resolver - this is the maximum number of parallel DNS requests that are
1869sent to the DNS server.
1870
1871=item C<PERL_ANYEVENT_RESOLV_CONF>
1872
1873The file to use instead of F</etc/resolv.conf> (or OS-specific
1874configuration) in the default resolver. When set to the empty string, no
1875default config will be used.
1876
1877=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1878
1879When neither C<ca_file> nor C<ca_path> was specified during
1880L<AnyEvent::TLS> context creation, and either of these environment
1881variables exist, they will be used to specify CA certificate locations
1882instead of a system-dependent default.
1883
1884=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1885
1886When these are set to C<1>, then the respective modules are not
1887loaded. Mostly good for testing AnyEvent itself.
1433 1888
1434=back 1889=back
1435 1890
1436=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1891=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1437 1892
1495 warn "read: $input\n"; # output what has been read 1950 warn "read: $input\n"; # output what has been read
1496 $cv->send if $input =~ /^q/i; # quit program if /^q/i 1951 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1497 }, 1952 },
1498 ); 1953 );
1499 1954
1500 my $time_watcher; # can only be used once
1501
1502 sub new_timer {
1503 $timer = AnyEvent->timer (after => 1, cb => sub { 1955 my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1504 warn "timeout\n"; # print 'timeout' about every second 1956 warn "timeout\n"; # print 'timeout' at most every second
1505 &new_timer; # and restart the time
1506 }); 1957 });
1507 }
1508
1509 new_timer; # create first timer
1510 1958
1511 $cv->recv; # wait until user enters /^q/i 1959 $cv->recv; # wait until user enters /^q/i
1512 1960
1513=head1 REAL-WORLD EXAMPLE 1961=head1 REAL-WORLD EXAMPLE
1514 1962
1645through AnyEvent. The benchmark creates a lot of timers (with a zero 2093through AnyEvent. The benchmark creates a lot of timers (with a zero
1646timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 2094timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1647which it is), lets them fire exactly once and destroys them again. 2095which it is), lets them fire exactly once and destroys them again.
1648 2096
1649Source code for this benchmark is found as F<eg/bench> in the AnyEvent 2097Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1650distribution. 2098distribution. It uses the L<AE> interface, which makes a real difference
2099for the EV and Perl backends only.
1651 2100
1652=head3 Explanation of the columns 2101=head3 Explanation of the columns
1653 2102
1654I<watcher> is the number of event watchers created/destroyed. Since 2103I<watcher> is the number of event watchers created/destroyed. Since
1655different event models feature vastly different performances, each event 2104different event models feature vastly different performances, each event
1676watcher. 2125watcher.
1677 2126
1678=head3 Results 2127=head3 Results
1679 2128
1680 name watchers bytes create invoke destroy comment 2129 name watchers bytes create invoke destroy comment
1681 EV/EV 400000 224 0.47 0.35 0.27 EV native interface 2130 EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1682 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 2131 EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1683 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 2132 Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1684 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 2133 Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1685 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 2134 Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1686 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 2135 Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
2136 IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
2137 IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1687 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 2138 Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1688 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 2139 Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1689 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 2140 POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1690 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 2141 POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1691 2142
1692=head3 Discussion 2143=head3 Discussion
1693 2144
1694The benchmark does I<not> measure scalability of the event loop very 2145The benchmark does I<not> measure scalability of the event loop very
1695well. For example, a select-based event loop (such as the pure perl one) 2146well. For example, a select-based event loop (such as the pure perl one)
1707benchmark machine, handling an event takes roughly 1600 CPU cycles with 2158benchmark machine, handling an event takes roughly 1600 CPU cycles with
1708EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU 2159EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1709cycles with POE. 2160cycles with POE.
1710 2161
1711C<EV> is the sole leader regarding speed and memory use, which are both 2162C<EV> is the sole leader regarding speed and memory use, which are both
1712maximal/minimal, respectively. Even when going through AnyEvent, it uses 2163maximal/minimal, respectively. When using the L<AE> API there is zero
2164overhead (when going through the AnyEvent API create is about 5-6 times
2165slower, with other times being equal, so still uses far less memory than
1713far less memory than any other event loop and is still faster than Event 2166any other event loop and is still faster than Event natively).
1714natively.
1715 2167
1716The pure perl implementation is hit in a few sweet spots (both the 2168The pure perl implementation is hit in a few sweet spots (both the
1717constant timeout and the use of a single fd hit optimisations in the perl 2169constant timeout and the use of a single fd hit optimisations in the perl
1718interpreter and the backend itself). Nevertheless this shows that it 2170interpreter and the backend itself). Nevertheless this shows that it
1719adds very little overhead in itself. Like any select-based backend its 2171adds very little overhead in itself. Like any select-based backend its
1720performance becomes really bad with lots of file descriptors (and few of 2172performance becomes really bad with lots of file descriptors (and few of
1721them active), of course, but this was not subject of this benchmark. 2173them active), of course, but this was not subject of this benchmark.
1722 2174
1723The C<Event> module has a relatively high setup and callback invocation 2175The C<Event> module has a relatively high setup and callback invocation
1724cost, but overall scores in on the third place. 2176cost, but overall scores in on the third place.
2177
2178C<IO::Async> performs admirably well, about on par with C<Event>, even
2179when using its pure perl backend.
1725 2180
1726C<Glib>'s memory usage is quite a bit higher, but it features a 2181C<Glib>'s memory usage is quite a bit higher, but it features a
1727faster callback invocation and overall ends up in the same class as 2182faster callback invocation and overall ends up in the same class as
1728C<Event>. However, Glib scales extremely badly, doubling the number of 2183C<Event>. However, Glib scales extremely badly, doubling the number of
1729watchers increases the processing time by more than a factor of four, 2184watchers increases the processing time by more than a factor of four,
1790In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 2245In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1791(1%) are active. This mirrors the activity of large servers with many 2246(1%) are active. This mirrors the activity of large servers with many
1792connections, most of which are idle at any one point in time. 2247connections, most of which are idle at any one point in time.
1793 2248
1794Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 2249Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1795distribution. 2250distribution. It uses the L<AE> interface, which makes a real difference
2251for the EV and Perl backends only.
1796 2252
1797=head3 Explanation of the columns 2253=head3 Explanation of the columns
1798 2254
1799I<sockets> is the number of sockets, and twice the number of "servers" (as 2255I<sockets> is the number of sockets, and twice the number of "servers" (as
1800each server has a read and write socket end). 2256each server has a read and write socket end).
1807it to another server. This includes deleting the old timeout and creating 2263it to another server. This includes deleting the old timeout and creating
1808a new one that moves the timeout into the future. 2264a new one that moves the timeout into the future.
1809 2265
1810=head3 Results 2266=head3 Results
1811 2267
1812 name sockets create request 2268 name sockets create request
1813 EV 20000 69.01 11.16 2269 EV 20000 62.66 7.99
1814 Perl 20000 73.32 35.87 2270 Perl 20000 68.32 32.64
1815 Event 20000 212.62 257.32 2271 IOAsync 20000 174.06 101.15 epoll
1816 Glib 20000 651.16 1896.30 2272 IOAsync 20000 174.67 610.84 poll
2273 Event 20000 202.69 242.91
2274 Glib 20000 557.01 1689.52
1817 POE 20000 349.67 12317.24 uses POE::Loop::Event 2275 POE 20000 341.54 12086.32 uses POE::Loop::Event
1818 2276
1819=head3 Discussion 2277=head3 Discussion
1820 2278
1821This benchmark I<does> measure scalability and overall performance of the 2279This benchmark I<does> measure scalability and overall performance of the
1822particular event loop. 2280particular event loop.
1824EV is again fastest. Since it is using epoll on my system, the setup time 2282EV is again fastest. Since it is using epoll on my system, the setup time
1825is relatively high, though. 2283is relatively high, though.
1826 2284
1827Perl surprisingly comes second. It is much faster than the C-based event 2285Perl surprisingly comes second. It is much faster than the C-based event
1828loops Event and Glib. 2286loops Event and Glib.
2287
2288IO::Async performs very well when using its epoll backend, and still quite
2289good compared to Glib when using its pure perl backend.
1829 2290
1830Event suffers from high setup time as well (look at its code and you will 2291Event suffers from high setup time as well (look at its code and you will
1831understand why). Callback invocation also has a high overhead compared to 2292understand why). Callback invocation also has a high overhead compared to
1832the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 2293the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1833uses select or poll in basically all documented configurations. 2294uses select or poll in basically all documented configurations.
1896=item * C-based event loops perform very well with small number of 2357=item * C-based event loops perform very well with small number of
1897watchers, as the management overhead dominates. 2358watchers, as the management overhead dominates.
1898 2359
1899=back 2360=back
1900 2361
2362=head2 THE IO::Lambda BENCHMARK
2363
2364Recently I was told about the benchmark in the IO::Lambda manpage, which
2365could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
2366simply compares IO::Lambda with POE, and IO::Lambda looks better (which
2367shouldn't come as a surprise to anybody). As such, the benchmark is
2368fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
2369very optimal. But how would AnyEvent compare when used without the extra
2370baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
2371
2372The benchmark itself creates an echo-server, and then, for 500 times,
2373connects to the echo server, sends a line, waits for the reply, and then
2374creates the next connection. This is a rather bad benchmark, as it doesn't
2375test the efficiency of the framework or much non-blocking I/O, but it is a
2376benchmark nevertheless.
2377
2378 name runtime
2379 Lambda/select 0.330 sec
2380 + optimized 0.122 sec
2381 Lambda/AnyEvent 0.327 sec
2382 + optimized 0.138 sec
2383 Raw sockets/select 0.077 sec
2384 POE/select, components 0.662 sec
2385 POE/select, raw sockets 0.226 sec
2386 POE/select, optimized 0.404 sec
2387
2388 AnyEvent/select/nb 0.085 sec
2389 AnyEvent/EV/nb 0.068 sec
2390 +state machine 0.134 sec
2391
2392The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
2393benchmarks actually make blocking connects and use 100% blocking I/O,
2394defeating the purpose of an event-based solution. All of the newly
2395written AnyEvent benchmarks use 100% non-blocking connects (using
2396AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
2397resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
2398generally require a lot more bookkeeping and event handling than blocking
2399connects (which involve a single syscall only).
2400
2401The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
2402offers similar expressive power as POE and IO::Lambda, using conventional
2403Perl syntax. This means that both the echo server and the client are 100%
2404non-blocking, further placing it at a disadvantage.
2405
2406As you can see, the AnyEvent + EV combination even beats the
2407hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2408backend easily beats IO::Lambda and POE.
2409
2410And even the 100% non-blocking version written using the high-level (and
2411slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2412higher level ("unoptimised") abstractions by a large margin, even though
2413it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2414
2415The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2416F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2417part of the IO::Lambda distribution and were used without any changes.
2418
1901 2419
1902=head1 SIGNALS 2420=head1 SIGNALS
1903 2421
1904AnyEvent currently installs handlers for these signals: 2422AnyEvent currently installs handlers for these signals:
1905 2423
1908=item SIGCHLD 2426=item SIGCHLD
1909 2427
1910A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2428A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1911emulation for event loops that do not support them natively. Also, some 2429emulation for event loops that do not support them natively. Also, some
1912event loops install a similar handler. 2430event loops install a similar handler.
2431
2432Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2433AnyEvent will reset it to default, to avoid losing child exit statuses.
1913 2434
1914=item SIGPIPE 2435=item SIGPIPE
1915 2436
1916A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 2437A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1917when AnyEvent gets loaded. 2438when AnyEvent gets loaded.
1929 2450
1930=back 2451=back
1931 2452
1932=cut 2453=cut
1933 2454
2455undef $SIG{CHLD}
2456 if $SIG{CHLD} eq 'IGNORE';
2457
1934$SIG{PIPE} = sub { } 2458$SIG{PIPE} = sub { }
1935 unless defined $SIG{PIPE}; 2459 unless defined $SIG{PIPE};
1936 2460
2461=head1 RECOMMENDED/OPTIONAL MODULES
2462
2463One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2464it's built-in modules) are required to use it.
2465
2466That does not mean that AnyEvent won't take advantage of some additional
2467modules if they are installed.
2468
2469This section explains which additional modules will be used, and how they
2470affect AnyEvent's operation.
2471
2472=over 4
2473
2474=item L<Async::Interrupt>
2475
2476This slightly arcane module is used to implement fast signal handling: To
2477my knowledge, there is no way to do completely race-free and quick
2478signal handling in pure perl. To ensure that signals still get
2479delivered, AnyEvent will start an interval timer to wake up perl (and
2480catch the signals) with some delay (default is 10 seconds, look for
2481C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2482
2483If this module is available, then it will be used to implement signal
2484catching, which means that signals will not be delayed, and the event loop
2485will not be interrupted regularly, which is more efficient (and good for
2486battery life on laptops).
2487
2488This affects not just the pure-perl event loop, but also other event loops
2489that have no signal handling on their own (e.g. Glib, Tk, Qt).
2490
2491Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2492and either employ their own workarounds (POE) or use AnyEvent's workaround
2493(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2494does nothing for those backends.
2495
2496=item L<EV>
2497
2498This module isn't really "optional", as it is simply one of the backend
2499event loops that AnyEvent can use. However, it is simply the best event
2500loop available in terms of features, speed and stability: It supports
2501the AnyEvent API optimally, implements all the watcher types in XS, does
2502automatic timer adjustments even when no monotonic clock is available,
2503can take avdantage of advanced kernel interfaces such as C<epoll> and
2504C<kqueue>, and is the fastest backend I<by far>. You can even embed
2505L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2506
2507=item L<Guard>
2508
2509The guard module, when used, will be used to implement
2510C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2511lot less memory), but otherwise doesn't affect guard operation much. It is
2512purely used for performance.
2513
2514=item L<JSON> and L<JSON::XS>
2515
2516One of these modules is required when you want to read or write JSON data
2517via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2518advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2519
2520In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2521installed.
2522
2523=item L<Net::SSLeay>
2524
2525Implementing TLS/SSL in Perl is certainly interesting, but not very
2526worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2527the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2528
2529=item L<Time::HiRes>
2530
2531This module is part of perl since release 5.008. It will be used when the
2532chosen event library does not come with a timing source on it's own. The
2533pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2534try to use a monotonic clock for timing stability.
2535
2536=back
2537
1937 2538
1938=head1 FORK 2539=head1 FORK
1939 2540
1940Most event libraries are not fork-safe. The ones who are usually are 2541Most event libraries are not fork-safe. The ones who are usually are
1941because they rely on inefficient but fork-safe C<select> or C<poll> 2542because they rely on inefficient but fork-safe C<select> or C<poll> calls
1942calls. Only L<EV> is fully fork-aware. 2543- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
2544are usually badly thought-out hacks that are incompatible with fork in
2545one way or another. Only L<EV> is fully fork-aware and ensures that you
2546continue event-processing in both parent and child (or both, if you know
2547what you are doing).
2548
2549This means that, in general, you cannot fork and do event processing in
2550the child if the event library was initialised before the fork (which
2551usually happens when the first AnyEvent watcher is created, or the library
2552is loaded).
1943 2553
1944If you have to fork, you must either do so I<before> creating your first 2554If you have to fork, you must either do so I<before> creating your first
1945watcher OR you must not use AnyEvent at all in the child. 2555watcher OR you must not use AnyEvent at all in the child OR you must do
2556something completely out of the scope of AnyEvent.
2557
2558The problem of doing event processing in the parent I<and> the child
2559is much more complicated: even for backends that I<are> fork-aware or
2560fork-safe, their behaviour is not usually what you want: fork clones all
2561watchers, that means all timers, I/O watchers etc. are active in both
2562parent and child, which is almost never what you want. USing C<exec>
2563to start worker children from some kind of manage rprocess is usually
2564preferred, because it is much easier and cleaner, at the expense of having
2565to have another binary.
1946 2566
1947 2567
1948=head1 SECURITY CONSIDERATIONS 2568=head1 SECURITY CONSIDERATIONS
1949 2569
1950AnyEvent can be forced to load any event model via 2570AnyEvent can be forced to load any event model via
1962 use AnyEvent; 2582 use AnyEvent;
1963 2583
1964Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 2584Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1965be used to probe what backend is used and gain other information (which is 2585be used to probe what backend is used and gain other information (which is
1966probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and 2586probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1967$ENV{PERL_ANYEGENT_STRICT}. 2587$ENV{PERL_ANYEVENT_STRICT}.
2588
2589Note that AnyEvent will remove I<all> environment variables starting with
2590C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
2591enabled.
1968 2592
1969 2593
1970=head1 BUGS 2594=head1 BUGS
1971 2595
1972Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 2596Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1984L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2608L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1985 2609
1986Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2610Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1987L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2611L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1988L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2612L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1989L<AnyEvent::Impl::POE>. 2613L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1990 2614
1991Non-blocking file handles, sockets, TCP clients and 2615Non-blocking file handles, sockets, TCP clients and
1992servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2616servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1993 2617
1994Asynchronous DNS: L<AnyEvent::DNS>. 2618Asynchronous DNS: L<AnyEvent::DNS>.
1995 2619
1996Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2620Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2621L<Coro::Event>,
1997 2622
1998Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2623Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2624L<AnyEvent::HTTP>.
1999 2625
2000 2626
2001=head1 AUTHOR 2627=head1 AUTHOR
2002 2628
2003 Marc Lehmann <schmorp@schmorp.de> 2629 Marc Lehmann <schmorp@schmorp.de>

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines