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Revision 1.108 by root, Sat May 10 00:22:02 2008 UTC vs.
Revision 1.133 by root, Sun May 25 03:44:03 2008 UTC

1=head1 NAME 1=head1 => NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - provide framework for multiple event loops
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops 5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6 6
15 my $w = AnyEvent->timer (after => $seconds, cb => sub { 15 my $w = AnyEvent->timer (after => $seconds, cb => sub {
16 ... 16 ...
17 }); 17 });
18 18
19 my $w = AnyEvent->condvar; # stores whether a condition was flagged 19 my $w = AnyEvent->condvar; # stores whether a condition was flagged
20 $w->send; # wake up current and all future recv's
20 $w->wait; # enters "main loop" till $condvar gets ->send 21 $w->recv; # enters "main loop" till $condvar gets ->send
21 $w->send; # wake up current and all future wait's
22 22
23=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 23=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24 24
25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26nowadays. So what is different about AnyEvent? 26nowadays. So what is different about AnyEvent?
57as those use one of the supported event loops. It is trivial to add new 57as those use one of the supported event loops. It is trivial to add new
58event loops to AnyEvent, too, so it is future-proof). 58event loops to AnyEvent, too, so it is future-proof).
59 59
60In addition to being free of having to use I<the one and only true event 60In addition to being free of having to use I<the one and only true event
61model>, AnyEvent also is free of bloat and policy: with POE or similar 61model>, AnyEvent also is free of bloat and policy: with POE or similar
62modules, you get an enourmous amount of code and strict rules you have to 62modules, you get an enormous amount of code and strict rules you have to
63follow. AnyEvent, on the other hand, is lean and up to the point, by only 63follow. AnyEvent, on the other hand, is lean and up to the point, by only
64offering the functionality that is necessary, in as thin as a wrapper as 64offering the functionality that is necessary, in as thin as a wrapper as
65technically possible. 65technically possible.
66 66
67Of course, if you want lots of policy (this can arguably be somewhat 67Of course, if you want lots of policy (this can arguably be somewhat
108 108
109=head1 WATCHERS 109=head1 WATCHERS
110 110
111AnyEvent has the central concept of a I<watcher>, which is an object that 111AnyEvent has the central concept of a I<watcher>, which is an object that
112stores relevant data for each kind of event you are waiting for, such as 112stores relevant data for each kind of event you are waiting for, such as
113the callback to call, the filehandle to watch, etc. 113the callback to call, the file handle to watch, etc.
114 114
115These watchers are normal Perl objects with normal Perl lifetime. After 115These watchers are normal Perl objects with normal Perl lifetime. After
116creating a watcher it will immediately "watch" for events and invoke the 116creating a watcher it will immediately "watch" for events and invoke the
117callback when the event occurs (of course, only when the event model 117callback when the event occurs (of course, only when the event model
118is in control). 118is in control).
237 237
238Although the callback might get passed parameters, their value and 238Although the callback might get passed parameters, their value and
239presence is undefined and you cannot rely on them. Portable AnyEvent 239presence is undefined and you cannot rely on them. Portable AnyEvent
240callbacks cannot use arguments passed to signal watcher callbacks. 240callbacks cannot use arguments passed to signal watcher callbacks.
241 241
242Multiple signal occurances can be clumped together into one callback 242Multiple signal occurrences can be clumped together into one callback
243invocation, and callback invocation will be synchronous. synchronous means 243invocation, and callback invocation will be synchronous. Synchronous means
244that it might take a while until the signal gets handled by the process, 244that it might take a while until the signal gets handled by the process,
245but it is guarenteed not to interrupt any other callbacks. 245but it is guaranteed not to interrupt any other callbacks.
246 246
247The main advantage of using these watchers is that you can share a signal 247The main advantage of using these watchers is that you can share a signal
248between multiple watchers. 248between multiple watchers.
249 249
250This watcher might use C<%SIG>, so programs overwriting those signals 250This watcher might use C<%SIG>, so programs overwriting those signals
278C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 278C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279 279
280Example: fork a process and wait for it 280Example: fork a process and wait for it
281 281
282 my $done = AnyEvent->condvar; 282 my $done = AnyEvent->condvar;
283
284 AnyEvent::detect; # force event module to be initialised
285 283
286 my $pid = fork or exit 5; 284 my $pid = fork or exit 5;
287 285
288 my $w = AnyEvent->child ( 286 my $w = AnyEvent->child (
289 pid => $pid, 287 pid => $pid,
293 $done->send; 291 $done->send;
294 }, 292 },
295 ); 293 );
296 294
297 # do something else, then wait for process exit 295 # do something else, then wait for process exit
298 $done->wait; 296 $done->recv;
299 297
300=head2 CONDITION VARIABLES 298=head2 CONDITION VARIABLES
301 299
302If you are familiar with some event loops you will know that all of them 300If you are familiar with some event loops you will know that all of them
303require you to run some blocking "loop", "run" or similar function that 301require you to run some blocking "loop", "run" or similar function that
312Condition variables can be created by calling the C<< AnyEvent->condvar 310Condition variables can be created by calling the C<< AnyEvent->condvar
313>> method, usually without arguments. The only argument pair allowed is 311>> method, usually without arguments. The only argument pair allowed is
314C<cb>, which specifies a callback to be called when the condition variable 312C<cb>, which specifies a callback to be called when the condition variable
315becomes true. 313becomes true.
316 314
317After creation, the conditon variable is "false" until it becomes "true" 315After creation, the condition variable is "false" until it becomes "true"
318by calling the C<send> method. 316by calling the C<send> method (or calling the condition variable as if it
317were a callback).
319 318
320Condition variables are similar to callbacks, except that you can 319Condition variables are similar to callbacks, except that you can
321optionally wait for them. They can also be called merge points - points 320optionally wait for them. They can also be called merge points - points
322in time where multiple outstandign events have been processed. And yet 321in time where multiple outstanding events have been processed. And yet
323another way to call them is transations - each condition variable can be 322another way to call them is transactions - each condition variable can be
324used to represent a transaction, which finishes at some point and delivers 323used to represent a transaction, which finishes at some point and delivers
325a result. 324a result.
326 325
327Condition variables are very useful to signal that something has finished, 326Condition variables are very useful to signal that something has finished,
328for example, if you write a module that does asynchronous http requests, 327for example, if you write a module that does asynchronous http requests,
329then a condition variable would be the ideal candidate to signal the 328then a condition variable would be the ideal candidate to signal the
330availability of results. The user can either act when the callback is 329availability of results. The user can either act when the callback is
331called or can synchronously C<< ->wait >> for the results. 330called or can synchronously C<< ->recv >> for the results.
332 331
333You can also use them to simulate traditional event loops - for example, 332You can also use them to simulate traditional event loops - for example,
334you can block your main program until an event occurs - for example, you 333you can block your main program until an event occurs - for example, you
335could C<< ->wait >> in your main program until the user clicks the Quit 334could C<< ->recv >> in your main program until the user clicks the Quit
336button of your app, which would C<< ->send >> the "quit" event. 335button of your app, which would C<< ->send >> the "quit" event.
337 336
338Note that condition variables recurse into the event loop - if you have 337Note that condition variables recurse into the event loop - if you have
339two pieces of code that call C<< ->wait >> in a round-robbin fashion, you 338two pieces of code that call C<< ->recv >> in a round-robin fashion, you
340lose. Therefore, condition variables are good to export to your caller, but 339lose. Therefore, condition variables are good to export to your caller, but
341you should avoid making a blocking wait yourself, at least in callbacks, 340you should avoid making a blocking wait yourself, at least in callbacks,
342as this asks for trouble. 341as this asks for trouble.
343 342
344Condition variables are represented by hash refs in perl, and the keys 343Condition variables are represented by hash refs in perl, and the keys
349 348
350There are two "sides" to a condition variable - the "producer side" which 349There are two "sides" to a condition variable - the "producer side" which
351eventually calls C<< -> send >>, and the "consumer side", which waits 350eventually calls C<< -> send >>, and the "consumer side", which waits
352for the send to occur. 351for the send to occur.
353 352
354Example: 353Example: wait for a timer.
355 354
356 # wait till the result is ready 355 # wait till the result is ready
357 my $result_ready = AnyEvent->condvar; 356 my $result_ready = AnyEvent->condvar;
358 357
359 # do something such as adding a timer 358 # do something such as adding a timer
365 cb => sub { $result_ready->send }, 364 cb => sub { $result_ready->send },
366 ); 365 );
367 366
368 # this "blocks" (while handling events) till the callback 367 # this "blocks" (while handling events) till the callback
369 # calls send 368 # calls send
370 $result_ready->wait; 369 $result_ready->recv;
370
371Example: wait for a timer, but take advantage of the fact that
372condition variables are also code references.
373
374 my $done = AnyEvent->condvar;
375 my $delay = AnyEvent->timer (after => 5, cb => $done);
376 $done->recv;
371 377
372=head3 METHODS FOR PRODUCERS 378=head3 METHODS FOR PRODUCERS
373 379
374These methods should only be used by the producing side, i.e. the 380These methods should only be used by the producing side, i.e. the
375code/module that eventually sends the signal. Note that it is also 381code/module that eventually sends the signal. Note that it is also
378 384
379=over 4 385=over 4
380 386
381=item $cv->send (...) 387=item $cv->send (...)
382 388
383Flag the condition as ready - a running C<< ->wait >> and all further 389Flag the condition as ready - a running C<< ->recv >> and all further
384calls to C<wait> will (eventually) return after this method has been 390calls to C<recv> will (eventually) return after this method has been
385called. If nobody is waiting the send will be remembered. 391called. If nobody is waiting the send will be remembered.
386 392
387If a callback has been set on the condition variable, it is called 393If a callback has been set on the condition variable, it is called
388immediately from within send. 394immediately from within send.
389 395
390Any arguments passed to the C<send> call will be returned by all 396Any arguments passed to the C<send> call will be returned by all
391future C<< ->wait >> calls. 397future C<< ->recv >> calls.
398
399Condition variables are overloaded so one can call them directly (as a
400code reference). Calling them directly is the same as calling C<send>.
392 401
393=item $cv->croak ($error) 402=item $cv->croak ($error)
394 403
395Similar to send, but causes all call's wait C<< ->wait >> to invoke 404Similar to send, but causes all call's to C<< ->recv >> to invoke
396C<Carp::croak> with the given error message/object/scalar. 405C<Carp::croak> with the given error message/object/scalar.
397 406
398This can be used to signal any errors to the condition variable 407This can be used to signal any errors to the condition variable
399user/consumer. 408user/consumer.
400 409
401=item $cv->begin ([group callback]) 410=item $cv->begin ([group callback])
402 411
403=item $cv->end 412=item $cv->end
413
414These two methods are EXPERIMENTAL and MIGHT CHANGE.
404 415
405These two methods can be used to combine many transactions/events into 416These two methods can be used to combine many transactions/events into
406one. For example, a function that pings many hosts in parallel might want 417one. For example, a function that pings many hosts in parallel might want
407to use a condition variable for the whole process. 418to use a condition variable for the whole process.
408 419
443doesn't execute once). 454doesn't execute once).
444 455
445This is the general pattern when you "fan out" into multiple subrequests: 456This is the general pattern when you "fan out" into multiple subrequests:
446use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 457use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
447is called at least once, and then, for each subrequest you start, call 458is called at least once, and then, for each subrequest you start, call
448C<begin> and for eahc subrequest you finish, call C<end>. 459C<begin> and for each subrequest you finish, call C<end>.
449 460
450=back 461=back
451 462
452=head3 METHODS FOR CONSUMERS 463=head3 METHODS FOR CONSUMERS
453 464
454These methods should only be used by the consuming side, i.e. the 465These methods should only be used by the consuming side, i.e. the
455code awaits the condition. 466code awaits the condition.
456 467
457=over 4 468=over 4
458 469
459=item $cv->wait 470=item $cv->recv
460 471
461Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak 472Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462>> methods have been called on c<$cv>, while servicing other watchers 473>> methods have been called on c<$cv>, while servicing other watchers
463normally. 474normally.
464 475
475(programs might want to do that to stay interactive), so I<if you are 486(programs might want to do that to stay interactive), so I<if you are
476using this from a module, never require a blocking wait>, but let the 487using this from a module, never require a blocking wait>, but let the
477caller decide whether the call will block or not (for example, by coupling 488caller decide whether the call will block or not (for example, by coupling
478condition variables with some kind of request results and supporting 489condition variables with some kind of request results and supporting
479callbacks so the caller knows that getting the result will not block, 490callbacks so the caller knows that getting the result will not block,
480while still suppporting blocking waits if the caller so desires). 491while still supporting blocking waits if the caller so desires).
481 492
482Another reason I<never> to C<< ->wait >> in a module is that you cannot 493Another reason I<never> to C<< ->recv >> in a module is that you cannot
483sensibly have two C<< ->wait >>'s in parallel, as that would require 494sensibly have two C<< ->recv >>'s in parallel, as that would require
484multiple interpreters or coroutines/threads, none of which C<AnyEvent> 495multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485can supply. 496can supply.
486 497
487The L<Coro> module, however, I<can> and I<does> supply coroutines and, in 498The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
488fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe 499fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
489versions and also integrates coroutines into AnyEvent, making blocking 500versions and also integrates coroutines into AnyEvent, making blocking
490C<< ->wait >> calls perfectly safe as long as they are done from another 501C<< ->recv >> calls perfectly safe as long as they are done from another
491coroutine (one that doesn't run the event loop). 502coroutine (one that doesn't run the event loop).
492 503
493You can ensure that C<< -wait >> never blocks by setting a callback and 504You can ensure that C<< -recv >> never blocks by setting a callback and
494only calling C<< ->wait >> from within that callback (or at a later 505only calling C<< ->recv >> from within that callback (or at a later
495time). This will work even when the event loop does not support blocking 506time). This will work even when the event loop does not support blocking
496waits otherwise. 507waits otherwise.
497 508
498=item $bool = $cv->ready 509=item $bool = $cv->ready
499 510
504 515
505This is a mutator function that returns the callback set and optionally 516This is a mutator function that returns the callback set and optionally
506replaces it before doing so. 517replaces it before doing so.
507 518
508The callback will be called when the condition becomes "true", i.e. when 519The callback will be called when the condition becomes "true", i.e. when
509C<send> or C<croak> are called. Calling C<wait> inside the callback 520C<send> or C<croak> are called. Calling C<recv> inside the callback
510or at any later time is guaranteed not to block. 521or at any later time is guaranteed not to block.
511 522
512=back 523=back
524
525=head3 MAINLOOP EMULATION
526
527Sometimes (often for short test scripts, or even standalone programs
528who only want to use AnyEvent), you I<do> want your program to block
529indefinitely in some event loop.
530
531In that case, you cna use a condition variable like this:
532
533 AnyEvent->condvar->recv;
534
535This has the effect of entering the event loop and looping forever.
536
537Note that usually your program has some exit condition, in which case
538it is better to use the "traditional" approach of storing a condition
539variable, waiting for it, and sending it when the program should exit
540cleanly.
541
513 542
514=head1 GLOBAL VARIABLES AND FUNCTIONS 543=head1 GLOBAL VARIABLES AND FUNCTIONS
515 544
516=over 4 545=over 4
517 546
549Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 578Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
550if necessary. You should only call this function right before you would 579if necessary. You should only call this function right before you would
551have created an AnyEvent watcher anyway, that is, as late as possible at 580have created an AnyEvent watcher anyway, that is, as late as possible at
552runtime. 581runtime.
553 582
583=item $guard = AnyEvent::post_detect { BLOCK }
584
585Arranges for the code block to be executed as soon as the event model is
586autodetected (or immediately if this has already happened).
587
588If called in scalar or list context, then it creates and returns an object
589that automatically removes the callback again when it is destroyed. See
590L<Coro::BDB> for a case where this is useful.
591
554=item @AnyEvent::detect 592=item @AnyEvent::post_detect
555 593
556If there are any code references in this array (you can C<push> to it 594If there are any code references in this array (you can C<push> to it
557before or after loading AnyEvent), then they will called directly after 595before or after loading AnyEvent), then they will called directly after
558the event loop has been chosen. 596the event loop has been chosen.
559 597
560You should check C<$AnyEvent::MODEL> before adding to this array, though: 598You should check C<$AnyEvent::MODEL> before adding to this array, though:
561if it contains a true value then the event loop has already been detected, 599if it contains a true value then the event loop has already been detected,
562and the array will be ignored. 600and the array will be ignored.
601
602Best use C<AnyEvent::post_detect { BLOCK }> instead.
563 603
564=back 604=back
565 605
566=head1 WHAT TO DO IN A MODULE 606=head1 WHAT TO DO IN A MODULE
567 607
571Be careful when you create watchers in the module body - AnyEvent will 611Be careful when you create watchers in the module body - AnyEvent will
572decide which event module to use as soon as the first method is called, so 612decide which event module to use as soon as the first method is called, so
573by calling AnyEvent in your module body you force the user of your module 613by calling AnyEvent in your module body you force the user of your module
574to load the event module first. 614to load the event module first.
575 615
576Never call C<< ->wait >> on a condition variable unless you I<know> that 616Never call C<< ->recv >> on a condition variable unless you I<know> that
577the C<< ->send >> method has been called on it already. This is 617the C<< ->send >> method has been called on it already. This is
578because it will stall the whole program, and the whole point of using 618because it will stall the whole program, and the whole point of using
579events is to stay interactive. 619events is to stay interactive.
580 620
581It is fine, however, to call C<< ->wait >> when the user of your module 621It is fine, however, to call C<< ->recv >> when the user of your module
582requests it (i.e. if you create a http request object ad have a method 622requests it (i.e. if you create a http request object ad have a method
583called C<results> that returns the results, it should call C<< ->wait >> 623called C<results> that returns the results, it should call C<< ->recv >>
584freely, as the user of your module knows what she is doing. always). 624freely, as the user of your module knows what she is doing. always).
585 625
586=head1 WHAT TO DO IN THE MAIN PROGRAM 626=head1 WHAT TO DO IN THE MAIN PROGRAM
587 627
588There will always be a single main program - the only place that should 628There will always be a single main program - the only place that should
622 662
623Provide read and write buffers and manages watchers for reads and writes. 663Provide read and write buffers and manages watchers for reads and writes.
624 664
625=item L<AnyEvent::Socket> 665=item L<AnyEvent::Socket>
626 666
627Provides a means to do non-blocking connects, accepts etc. 667Provides various utility functions for (internet protocol) sockets,
668addresses and name resolution. Also functions to create non-blocking tcp
669connections or tcp servers, with IPv6 and SRV record support and more.
628 670
629=item L<AnyEvent::HTTPD> 671=item L<AnyEvent::HTTPD>
630 672
631Provides a simple web application server framework. 673Provides a simple web application server framework.
632 674
633=item L<AnyEvent::DNS> 675=item L<AnyEvent::DNS>
634 676
635Provides asynchronous DNS resolver capabilities, beyond what 677Provides rich asynchronous DNS resolver capabilities.
636L<AnyEvent::Util> offers.
637 678
638=item L<AnyEvent::FastPing> 679=item L<AnyEvent::FastPing>
639 680
640The fastest ping in the west. 681The fastest ping in the west.
641 682
658 699
659=item L<Coro> 700=item L<Coro>
660 701
661Has special support for AnyEvent via L<Coro::AnyEvent>. 702Has special support for AnyEvent via L<Coro::AnyEvent>.
662 703
704=item L<AnyEvent::AIO>, L<IO::AIO>
705
706Truly asynchronous I/O, should be in the toolbox of every event
707programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
708together.
709
710=item L<AnyEvent::BDB>, L<BDB>
711
712Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
713IO::AIO and AnyEvent together.
714
663=item L<IO::Lambda> 715=item L<IO::Lambda>
664 716
665The lambda approach to I/O - don't ask, look there. Can use AnyEvent. 717The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
666
667=item L<IO::AIO>
668
669Truly asynchronous I/O, should be in the toolbox of every event
670programmer. Can be trivially made to use AnyEvent.
671
672=item L<BDB>
673
674Truly asynchronous Berkeley DB access. Can be trivially made to use
675AnyEvent.
676 718
677=back 719=back
678 720
679=cut 721=cut
680 722
683no warnings; 725no warnings;
684use strict; 726use strict;
685 727
686use Carp; 728use Carp;
687 729
688our $VERSION = '3.4'; 730our $VERSION = '4.03';
689our $MODEL; 731our $MODEL;
690 732
691our $AUTOLOAD; 733our $AUTOLOAD;
692our @ISA; 734our @ISA;
693 735
694our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 736our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
695 737
696our @REGISTRY; 738our @REGISTRY;
739
740our %PROTOCOL; # (ipv4|ipv6) => (1|2)
741
742{
743 my $idx;
744 $PROTOCOL{$_} = ++$idx
745 for split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
746}
697 747
698my @models = ( 748my @models = (
699 [EV:: => AnyEvent::Impl::EV::], 749 [EV:: => AnyEvent::Impl::EV::],
700 [Event:: => AnyEvent::Impl::Event::], 750 [Event:: => AnyEvent::Impl::Event::],
701 [Tk:: => AnyEvent::Impl::Tk::], 751 [Tk:: => AnyEvent::Impl::Tk::],
709 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 759 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
710); 760);
711 761
712our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); 762our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
713 763
714our @detect; 764our @post_detect;
765
766sub post_detect(&) {
767 my ($cb) = @_;
768
769 if ($MODEL) {
770 $cb->();
771
772 1
773 } else {
774 push @post_detect, $cb;
775
776 defined wantarray
777 ? bless \$cb, "AnyEvent::Util::PostDetect"
778 : ()
779 }
780}
781
782sub AnyEvent::Util::PostDetect::DESTROY {
783 @post_detect = grep $_ != ${$_[0]}, @post_detect;
784}
715 785
716sub detect() { 786sub detect() {
717 unless ($MODEL) { 787 unless ($MODEL) {
718 no strict 'refs'; 788 no strict 'refs';
719 789
760 } 830 }
761 831
762 unshift @ISA, $MODEL; 832 unshift @ISA, $MODEL;
763 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 833 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
764 834
765 (shift @detect)->() while @detect; 835 (shift @post_detect)->() while @post_detect;
766 } 836 }
767 837
768 $MODEL 838 $MODEL
769} 839}
770 840
780 $class->$func (@_); 850 $class->$func (@_);
781} 851}
782 852
783package AnyEvent::Base; 853package AnyEvent::Base;
784 854
785# default implementation for ->condvar, ->wait, ->broadcast 855# default implementation for ->condvar
786 856
787sub condvar { 857sub condvar {
788 bless \my $flag, "AnyEvent::Base::CondVar" 858 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
789}
790
791sub AnyEvent::Base::CondVar::broadcast {
792 ${$_[0]}++;
793}
794
795sub AnyEvent::Base::CondVar::wait {
796 AnyEvent->one_event while !${$_[0]};
797} 859}
798 860
799# default implementation for ->signal 861# default implementation for ->signal
800 862
801our %SIG_CB; 863our %SIG_CB;
875 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 937 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
876 938
877 undef $CHLD_W unless keys %PID_CB; 939 undef $CHLD_W unless keys %PID_CB;
878} 940}
879 941
942package AnyEvent::CondVar;
943
944our @ISA = AnyEvent::CondVar::Base::;
945
946package AnyEvent::CondVar::Base;
947
948use overload
949 '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
950 fallback => 1;
951
952sub _send {
953 # nop
954}
955
956sub send {
957 my $cv = shift;
958 $cv->{_ae_sent} = [@_];
959 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
960 $cv->_send;
961}
962
963sub croak {
964 $_[0]{_ae_croak} = $_[1];
965 $_[0]->send;
966}
967
968sub ready {
969 $_[0]{_ae_sent}
970}
971
972sub _wait {
973 AnyEvent->one_event while !$_[0]{_ae_sent};
974}
975
976sub recv {
977 $_[0]->_wait;
978
979 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
980 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
981}
982
983sub cb {
984 $_[0]{_ae_cb} = $_[1] if @_ > 1;
985 $_[0]{_ae_cb}
986}
987
988sub begin {
989 ++$_[0]{_ae_counter};
990 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
991}
992
993sub end {
994 return if --$_[0]{_ae_counter};
995 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
996}
997
998# undocumented/compatibility with pre-3.4
999*broadcast = \&send;
1000*wait = \&_wait;
1001
880=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1002=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
881 1003
882This is an advanced topic that you do not normally need to use AnyEvent in 1004This is an advanced topic that you do not normally need to use AnyEvent in
883a module. This section is only of use to event loop authors who want to 1005a module. This section is only of use to event loop authors who want to
884provide AnyEvent compatibility. 1006provide AnyEvent compatibility.
940model it chooses. 1062model it chooses.
941 1063
942=item C<PERL_ANYEVENT_MODEL> 1064=item C<PERL_ANYEVENT_MODEL>
943 1065
944This can be used to specify the event model to be used by AnyEvent, before 1066This can be used to specify the event model to be used by AnyEvent, before
945autodetection and -probing kicks in. It must be a string consisting 1067auto detection and -probing kicks in. It must be a string consisting
946entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 1068entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
947and the resulting module name is loaded and if the load was successful, 1069and the resulting module name is loaded and if the load was successful,
948used as event model. If it fails to load AnyEvent will proceed with 1070used as event model. If it fails to load AnyEvent will proceed with
949autodetection and -probing. 1071auto detection and -probing.
950 1072
951This functionality might change in future versions. 1073This functionality might change in future versions.
952 1074
953For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 1075For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
954could start your program like this: 1076could start your program like this:
955 1077
956 PERL_ANYEVENT_MODEL=Perl perl ... 1078 PERL_ANYEVENT_MODEL=Perl perl ...
1079
1080=item C<PERL_ANYEVENT_PROTOCOLS>
1081
1082Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1083for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1084of auto probing).
1085
1086Must be set to a comma-separated list of protocols or address families,
1087current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1088used, and preference will be given to protocols mentioned earlier in the
1089list.
1090
1091This variable can effectively be used for denial-of-service attacks
1092against local programs (e.g. when setuid), although the impact is likely
1093small, as the program has to handle connection errors already-
1094
1095Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1096but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1097- only support IPv4, never try to resolve or contact IPv6
1098addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1099IPv6, but prefer IPv6 over IPv4.
1100
1101=item C<PERL_ANYEVENT_EDNS0>
1102
1103Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1104for DNS. This extension is generally useful to reduce DNS traffic, but
1105some (broken) firewalls drop such DNS packets, which is why it is off by
1106default.
1107
1108Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1109EDNS0 in its DNS requests.
957 1110
958=back 1111=back
959 1112
960=head1 EXAMPLE PROGRAM 1113=head1 EXAMPLE PROGRAM
961 1114
972 poll => 'r', 1125 poll => 'r',
973 cb => sub { 1126 cb => sub {
974 warn "io event <$_[0]>\n"; # will always output <r> 1127 warn "io event <$_[0]>\n"; # will always output <r>
975 chomp (my $input = <STDIN>); # read a line 1128 chomp (my $input = <STDIN>); # read a line
976 warn "read: $input\n"; # output what has been read 1129 warn "read: $input\n"; # output what has been read
977 $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i 1130 $cv->send if $input =~ /^q/i; # quit program if /^q/i
978 }, 1131 },
979 ); 1132 );
980 1133
981 my $time_watcher; # can only be used once 1134 my $time_watcher; # can only be used once
982 1135
987 }); 1140 });
988 } 1141 }
989 1142
990 new_timer; # create first timer 1143 new_timer; # create first timer
991 1144
992 $cv->wait; # wait until user enters /^q/i 1145 $cv->recv; # wait until user enters /^q/i
993 1146
994=head1 REAL-WORLD EXAMPLE 1147=head1 REAL-WORLD EXAMPLE
995 1148
996Consider the L<Net::FCP> module. It features (among others) the following 1149Consider the L<Net::FCP> module. It features (among others) the following
997API calls, which are to freenet what HTTP GET requests are to http: 1150API calls, which are to freenet what HTTP GET requests are to http:
1047 syswrite $txn->{fh}, $txn->{request} 1200 syswrite $txn->{fh}, $txn->{request}
1048 or die "connection or write error"; 1201 or die "connection or write error";
1049 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); 1202 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1050 1203
1051Again, C<fh_ready_r> waits till all data has arrived, and then stores the 1204Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1052result and signals any possible waiters that the request ahs finished: 1205result and signals any possible waiters that the request has finished:
1053 1206
1054 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; 1207 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1055 1208
1056 if (end-of-file or data complete) { 1209 if (end-of-file or data complete) {
1057 $txn->{result} = $txn->{buf}; 1210 $txn->{result} = $txn->{buf};
1058 $txn->{finished}->broadcast; 1211 $txn->{finished}->send;
1059 $txb->{cb}->($txn) of $txn->{cb}; # also call callback 1212 $txb->{cb}->($txn) of $txn->{cb}; # also call callback
1060 } 1213 }
1061 1214
1062The C<result> method, finally, just waits for the finished signal (if the 1215The C<result> method, finally, just waits for the finished signal (if the
1063request was already finished, it doesn't wait, of course, and returns the 1216request was already finished, it doesn't wait, of course, and returns the
1064data: 1217data:
1065 1218
1066 $txn->{finished}->wait; 1219 $txn->{finished}->recv;
1067 return $txn->{result}; 1220 return $txn->{result};
1068 1221
1069The actual code goes further and collects all errors (C<die>s, exceptions) 1222The actual code goes further and collects all errors (C<die>s, exceptions)
1070that occured during request processing. The C<result> method detects 1223that occurred during request processing. The C<result> method detects
1071whether an exception as thrown (it is stored inside the $txn object) 1224whether an exception as thrown (it is stored inside the $txn object)
1072and just throws the exception, which means connection errors and other 1225and just throws the exception, which means connection errors and other
1073problems get reported tot he code that tries to use the result, not in a 1226problems get reported tot he code that tries to use the result, not in a
1074random callback. 1227random callback.
1075 1228
1106 1259
1107 my $quit = AnyEvent->condvar; 1260 my $quit = AnyEvent->condvar;
1108 1261
1109 $fcp->txn_client_get ($url)->cb (sub { 1262 $fcp->txn_client_get ($url)->cb (sub {
1110 ... 1263 ...
1111 $quit->broadcast; 1264 $quit->send;
1112 }); 1265 });
1113 1266
1114 $quit->wait; 1267 $quit->recv;
1115 1268
1116 1269
1117=head1 BENCHMARKS 1270=head1 BENCHMARKS
1118 1271
1119To give you an idea of the performance and overheads that AnyEvent adds 1272To give you an idea of the performance and overheads that AnyEvent adds
1121of various event loops I prepared some benchmarks. 1274of various event loops I prepared some benchmarks.
1122 1275
1123=head2 BENCHMARKING ANYEVENT OVERHEAD 1276=head2 BENCHMARKING ANYEVENT OVERHEAD
1124 1277
1125Here is a benchmark of various supported event models used natively and 1278Here is a benchmark of various supported event models used natively and
1126through anyevent. The benchmark creates a lot of timers (with a zero 1279through AnyEvent. The benchmark creates a lot of timers (with a zero
1127timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 1280timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1128which it is), lets them fire exactly once and destroys them again. 1281which it is), lets them fire exactly once and destroys them again.
1129 1282
1130Source code for this benchmark is found as F<eg/bench> in the AnyEvent 1283Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1131distribution. 1284distribution.
1148all watchers, to avoid adding memory overhead. That means closure creation 1301all watchers, to avoid adding memory overhead. That means closure creation
1149and memory usage is not included in the figures. 1302and memory usage is not included in the figures.
1150 1303
1151I<invoke> is the time, in microseconds, used to invoke a simple 1304I<invoke> is the time, in microseconds, used to invoke a simple
1152callback. The callback simply counts down a Perl variable and after it was 1305callback. The callback simply counts down a Perl variable and after it was
1153invoked "watcher" times, it would C<< ->broadcast >> a condvar once to 1306invoked "watcher" times, it would C<< ->send >> a condvar once to
1154signal the end of this phase. 1307signal the end of this phase.
1155 1308
1156I<destroy> is the time, in microseconds, that it takes to destroy a single 1309I<destroy> is the time, in microseconds, that it takes to destroy a single
1157watcher. 1310watcher.
1158 1311
1254 1407
1255=back 1408=back
1256 1409
1257=head2 BENCHMARKING THE LARGE SERVER CASE 1410=head2 BENCHMARKING THE LARGE SERVER CASE
1258 1411
1259This benchmark atcually benchmarks the event loop itself. It works by 1412This benchmark actually benchmarks the event loop itself. It works by
1260creating a number of "servers": each server consists of a socketpair, a 1413creating a number of "servers": each server consists of a socket pair, a
1261timeout watcher that gets reset on activity (but never fires), and an I/O 1414timeout watcher that gets reset on activity (but never fires), and an I/O
1262watcher waiting for input on one side of the socket. Each time the socket 1415watcher waiting for input on one side of the socket. Each time the socket
1263watcher reads a byte it will write that byte to a random other "server". 1416watcher reads a byte it will write that byte to a random other "server".
1264 1417
1265The effect is that there will be a lot of I/O watchers, only part of which 1418The effect is that there will be a lot of I/O watchers, only part of which
1266are active at any one point (so there is a constant number of active 1419are active at any one point (so there is a constant number of active
1267fds for each loop iterstaion, but which fds these are is random). The 1420fds for each loop iteration, but which fds these are is random). The
1268timeout is reset each time something is read because that reflects how 1421timeout is reset each time something is read because that reflects how
1269most timeouts work (and puts extra pressure on the event loops). 1422most timeouts work (and puts extra pressure on the event loops).
1270 1423
1271In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 1424In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1272(1%) are active. This mirrors the activity of large servers with many 1425(1%) are active. This mirrors the activity of large servers with many
1273connections, most of which are idle at any one point in time. 1426connections, most of which are idle at any one point in time.
1274 1427
1275Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 1428Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1276distribution. 1429distribution.
1278=head3 Explanation of the columns 1431=head3 Explanation of the columns
1279 1432
1280I<sockets> is the number of sockets, and twice the number of "servers" (as 1433I<sockets> is the number of sockets, and twice the number of "servers" (as
1281each server has a read and write socket end). 1434each server has a read and write socket end).
1282 1435
1283I<create> is the time it takes to create a socketpair (which is 1436I<create> is the time it takes to create a socket pair (which is
1284nontrivial) and two watchers: an I/O watcher and a timeout watcher. 1437nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1285 1438
1286I<request>, the most important value, is the time it takes to handle a 1439I<request>, the most important value, is the time it takes to handle a
1287single "request", that is, reading the token from the pipe and forwarding 1440single "request", that is, reading the token from the pipe and forwarding
1288it to another server. This includes deleting the old timeout and creating 1441it to another server. This includes deleting the old timeout and creating
1361speed most when you have lots of watchers, not when you only have a few of 1514speed most when you have lots of watchers, not when you only have a few of
1362them). 1515them).
1363 1516
1364EV is again fastest. 1517EV is again fastest.
1365 1518
1366Perl again comes second. It is noticably faster than the C-based event 1519Perl again comes second. It is noticeably faster than the C-based event
1367loops Event and Glib, although the difference is too small to really 1520loops Event and Glib, although the difference is too small to really
1368matter. 1521matter.
1369 1522
1370POE also performs much better in this case, but is is still far behind the 1523POE also performs much better in this case, but is is still far behind the
1371others. 1524others.
1411probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1564probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1412 1565
1413 1566
1414=head1 SEE ALSO 1567=head1 SEE ALSO
1415 1568
1569Utility functions: L<AnyEvent::Util>.
1570
1416Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 1571Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1417L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 1572L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1418 1573
1419Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 1574Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1420L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 1575L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1421L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 1576L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1422L<AnyEvent::Impl::POE>. 1577L<AnyEvent::Impl::POE>.
1423 1578
1579Non-blocking file handles, sockets, TCP clients and
1580servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
1581
1582Asynchronous DNS: L<AnyEvent::DNS>.
1583
1424Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 1584Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1425 1585
1426Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. 1586Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1427 1587
1428 1588
1429=head1 AUTHOR 1589=head1 AUTHOR
1430 1590
1431 Marc Lehmann <schmorp@schmorp.de> 1591 Marc Lehmann <schmorp@schmorp.de>

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