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Revision 1.110 by root, Sat May 10 00:57:31 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
554=item $guard = AnyEvent::on_detect { BLOCK } 583=item $guard = AnyEvent::post_detect { BLOCK }
555 584
556Arranges for the code block to be executed as soon as the event model is 585Arranges for the code block to be executed as soon as the event model is
557autodetected (or immediately if this has already happened). 586autodetected (or immediately if this has already happened).
558 587
559If called in scalar or list context, then it creates and returns an object 588If called in scalar or list context, then it creates and returns an object
560that automatically removes the callback again when it is destroyed. 589that automatically removes the callback again when it is destroyed. See
590L<Coro::BDB> for a case where this is useful.
561 591
562=item @AnyEvent::on_detect 592=item @AnyEvent::post_detect
563 593
564If there are any code references in this array (you can C<push> to it 594If there are any code references in this array (you can C<push> to it
565before or after loading AnyEvent), then they will called directly after 595before or after loading AnyEvent), then they will called directly after
566the event loop has been chosen. 596the event loop has been chosen.
567 597
568You should check C<$AnyEvent::MODEL> before adding to this array, though: 598You should check C<$AnyEvent::MODEL> before adding to this array, though:
569if 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,
570and the array will be ignored. 600and the array will be ignored.
571 601
572Best use C<AnyEvent::on_detect { BLOCK }> instead. 602Best use C<AnyEvent::post_detect { BLOCK }> instead.
573 603
574=back 604=back
575 605
576=head1 WHAT TO DO IN A MODULE 606=head1 WHAT TO DO IN A MODULE
577 607
581Be careful when you create watchers in the module body - AnyEvent will 611Be careful when you create watchers in the module body - AnyEvent will
582decide 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
583by 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
584to load the event module first. 614to load the event module first.
585 615
586Never 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
587the C<< ->send >> method has been called on it already. This is 617the C<< ->send >> method has been called on it already. This is
588because 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
589events is to stay interactive. 619events is to stay interactive.
590 620
591It 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
592requests 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
593called C<results> that returns the results, it should call C<< ->wait >> 623called C<results> that returns the results, it should call C<< ->recv >>
594freely, 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).
595 625
596=head1 WHAT TO DO IN THE MAIN PROGRAM 626=head1 WHAT TO DO IN THE MAIN PROGRAM
597 627
598There 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
632 662
633Provide read and write buffers and manages watchers for reads and writes. 663Provide read and write buffers and manages watchers for reads and writes.
634 664
635=item L<AnyEvent::Socket> 665=item L<AnyEvent::Socket>
636 666
637Provides 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.
638 670
639=item L<AnyEvent::HTTPD> 671=item L<AnyEvent::HTTPD>
640 672
641Provides a simple web application server framework. 673Provides a simple web application server framework.
642 674
643=item L<AnyEvent::DNS> 675=item L<AnyEvent::DNS>
644 676
645Provides asynchronous DNS resolver capabilities, beyond what 677Provides rich asynchronous DNS resolver capabilities.
646L<AnyEvent::Util> offers.
647 678
648=item L<AnyEvent::FastPing> 679=item L<AnyEvent::FastPing>
649 680
650The fastest ping in the west. 681The fastest ping in the west.
651 682
668 699
669=item L<Coro> 700=item L<Coro>
670 701
671Has special support for AnyEvent via L<Coro::AnyEvent>. 702Has special support for AnyEvent via L<Coro::AnyEvent>.
672 703
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
673=item L<IO::Lambda> 715=item L<IO::Lambda>
674 716
675The 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.
676
677=item L<IO::AIO>
678
679Truly asynchronous I/O, should be in the toolbox of every event
680programmer. Can be trivially made to use AnyEvent.
681
682=item L<BDB>
683
684Truly asynchronous Berkeley DB access. Can be trivially made to use
685AnyEvent.
686 718
687=back 719=back
688 720
689=cut 721=cut
690 722
693no warnings; 725no warnings;
694use strict; 726use strict;
695 727
696use Carp; 728use Carp;
697 729
698our $VERSION = '3.4'; 730our $VERSION = '4.03';
699our $MODEL; 731our $MODEL;
700 732
701our $AUTOLOAD; 733our $AUTOLOAD;
702our @ISA; 734our @ISA;
703 735
704our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 736our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
705 737
706our @REGISTRY; 738our @REGISTRY;
739
740our %PROTOCOL; # (ipv4|ipv6) => (1|2)
741
742{
743 my $idx;
744 $PROTOCOL{$_} = ++$idx
745 for split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
746}
707 747
708my @models = ( 748my @models = (
709 [EV:: => AnyEvent::Impl::EV::], 749 [EV:: => AnyEvent::Impl::EV::],
710 [Event:: => AnyEvent::Impl::Event::], 750 [Event:: => AnyEvent::Impl::Event::],
711 [Tk:: => AnyEvent::Impl::Tk::], 751 [Tk:: => AnyEvent::Impl::Tk::],
719 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 759 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
720); 760);
721 761
722our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); 762our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
723 763
724our @on_detect; 764our @post_detect;
725 765
726sub on_detect(&) { 766sub post_detect(&) {
727 my ($cb) = @_; 767 my ($cb) = @_;
728 768
729 if ($MODEL) { 769 if ($MODEL) {
730 $cb->(); 770 $cb->();
731 771
732 1 772 1
733 } else { 773 } else {
734 push @on_detect, $cb; 774 push @post_detect, $cb;
735 775
736 defined wantarray 776 defined wantarray
737 ? bless \$cb, "AnyEvent::Util::Guard" 777 ? bless \$cb, "AnyEvent::Util::PostDetect"
738 : () 778 : ()
739 } 779 }
740} 780}
741 781
742sub AnyEvent::Util::Guard::DESTROY { 782sub AnyEvent::Util::PostDetect::DESTROY {
743 @on_detect = grep $_ != ${$_[0]}, @on_detect; 783 @post_detect = grep $_ != ${$_[0]}, @post_detect;
744} 784}
745 785
746sub detect() { 786sub detect() {
747 unless ($MODEL) { 787 unless ($MODEL) {
748 no strict 'refs'; 788 no strict 'refs';
790 } 830 }
791 831
792 unshift @ISA, $MODEL; 832 unshift @ISA, $MODEL;
793 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 833 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
794 834
795 (shift @on_detect)->() while @on_detect; 835 (shift @post_detect)->() while @post_detect;
796 } 836 }
797 837
798 $MODEL 838 $MODEL
799} 839}
800 840
810 $class->$func (@_); 850 $class->$func (@_);
811} 851}
812 852
813package AnyEvent::Base; 853package AnyEvent::Base;
814 854
815# default implementation for ->condvar, ->wait, ->broadcast 855# default implementation for ->condvar
816 856
817sub condvar { 857sub condvar {
818 bless \my $flag, "AnyEvent::Base::CondVar" 858 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
819}
820
821sub AnyEvent::Base::CondVar::broadcast {
822 ${$_[0]}++;
823}
824
825sub AnyEvent::Base::CondVar::wait {
826 AnyEvent->one_event while !${$_[0]};
827} 859}
828 860
829# default implementation for ->signal 861# default implementation for ->signal
830 862
831our %SIG_CB; 863our %SIG_CB;
905 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 937 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
906 938
907 undef $CHLD_W unless keys %PID_CB; 939 undef $CHLD_W unless keys %PID_CB;
908} 940}
909 941
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
910=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1002=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
911 1003
912This 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
913a 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
914provide AnyEvent compatibility. 1006provide AnyEvent compatibility.
970model it chooses. 1062model it chooses.
971 1063
972=item C<PERL_ANYEVENT_MODEL> 1064=item C<PERL_ANYEVENT_MODEL>
973 1065
974This 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
975autodetection and -probing kicks in. It must be a string consisting 1067auto detection and -probing kicks in. It must be a string consisting
976entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 1068entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
977and 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,
978used 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
979autodetection and -probing. 1071auto detection and -probing.
980 1072
981This functionality might change in future versions. 1073This functionality might change in future versions.
982 1074
983For 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
984could start your program like this: 1076could start your program like this:
985 1077
986 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.
987 1110
988=back 1111=back
989 1112
990=head1 EXAMPLE PROGRAM 1113=head1 EXAMPLE PROGRAM
991 1114
1002 poll => 'r', 1125 poll => 'r',
1003 cb => sub { 1126 cb => sub {
1004 warn "io event <$_[0]>\n"; # will always output <r> 1127 warn "io event <$_[0]>\n"; # will always output <r>
1005 chomp (my $input = <STDIN>); # read a line 1128 chomp (my $input = <STDIN>); # read a line
1006 warn "read: $input\n"; # output what has been read 1129 warn "read: $input\n"; # output what has been read
1007 $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i 1130 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1008 }, 1131 },
1009 ); 1132 );
1010 1133
1011 my $time_watcher; # can only be used once 1134 my $time_watcher; # can only be used once
1012 1135
1017 }); 1140 });
1018 } 1141 }
1019 1142
1020 new_timer; # create first timer 1143 new_timer; # create first timer
1021 1144
1022 $cv->wait; # wait until user enters /^q/i 1145 $cv->recv; # wait until user enters /^q/i
1023 1146
1024=head1 REAL-WORLD EXAMPLE 1147=head1 REAL-WORLD EXAMPLE
1025 1148
1026Consider the L<Net::FCP> module. It features (among others) the following 1149Consider the L<Net::FCP> module. It features (among others) the following
1027API 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:
1077 syswrite $txn->{fh}, $txn->{request} 1200 syswrite $txn->{fh}, $txn->{request}
1078 or die "connection or write error"; 1201 or die "connection or write error";
1079 $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 });
1080 1203
1081Again, 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
1082result and signals any possible waiters that the request ahs finished: 1205result and signals any possible waiters that the request has finished:
1083 1206
1084 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; 1207 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1085 1208
1086 if (end-of-file or data complete) { 1209 if (end-of-file or data complete) {
1087 $txn->{result} = $txn->{buf}; 1210 $txn->{result} = $txn->{buf};
1088 $txn->{finished}->broadcast; 1211 $txn->{finished}->send;
1089 $txb->{cb}->($txn) of $txn->{cb}; # also call callback 1212 $txb->{cb}->($txn) of $txn->{cb}; # also call callback
1090 } 1213 }
1091 1214
1092The 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
1093request 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
1094data: 1217data:
1095 1218
1096 $txn->{finished}->wait; 1219 $txn->{finished}->recv;
1097 return $txn->{result}; 1220 return $txn->{result};
1098 1221
1099The 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)
1100that occured during request processing. The C<result> method detects 1223that occurred during request processing. The C<result> method detects
1101whether an exception as thrown (it is stored inside the $txn object) 1224whether an exception as thrown (it is stored inside the $txn object)
1102and just throws the exception, which means connection errors and other 1225and just throws the exception, which means connection errors and other
1103problems 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
1104random callback. 1227random callback.
1105 1228
1136 1259
1137 my $quit = AnyEvent->condvar; 1260 my $quit = AnyEvent->condvar;
1138 1261
1139 $fcp->txn_client_get ($url)->cb (sub { 1262 $fcp->txn_client_get ($url)->cb (sub {
1140 ... 1263 ...
1141 $quit->broadcast; 1264 $quit->send;
1142 }); 1265 });
1143 1266
1144 $quit->wait; 1267 $quit->recv;
1145 1268
1146 1269
1147=head1 BENCHMARKS 1270=head1 BENCHMARKS
1148 1271
1149To 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
1151of various event loops I prepared some benchmarks. 1274of various event loops I prepared some benchmarks.
1152 1275
1153=head2 BENCHMARKING ANYEVENT OVERHEAD 1276=head2 BENCHMARKING ANYEVENT OVERHEAD
1154 1277
1155Here is a benchmark of various supported event models used natively and 1278Here is a benchmark of various supported event models used natively and
1156through anyevent. The benchmark creates a lot of timers (with a zero 1279through AnyEvent. The benchmark creates a lot of timers (with a zero
1157timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 1280timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1158which it is), lets them fire exactly once and destroys them again. 1281which it is), lets them fire exactly once and destroys them again.
1159 1282
1160Source 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
1161distribution. 1284distribution.
1178all watchers, to avoid adding memory overhead. That means closure creation 1301all watchers, to avoid adding memory overhead. That means closure creation
1179and memory usage is not included in the figures. 1302and memory usage is not included in the figures.
1180 1303
1181I<invoke> is the time, in microseconds, used to invoke a simple 1304I<invoke> is the time, in microseconds, used to invoke a simple
1182callback. 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
1183invoked "watcher" times, it would C<< ->broadcast >> a condvar once to 1306invoked "watcher" times, it would C<< ->send >> a condvar once to
1184signal the end of this phase. 1307signal the end of this phase.
1185 1308
1186I<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
1187watcher. 1310watcher.
1188 1311
1284 1407
1285=back 1408=back
1286 1409
1287=head2 BENCHMARKING THE LARGE SERVER CASE 1410=head2 BENCHMARKING THE LARGE SERVER CASE
1288 1411
1289This benchmark atcually benchmarks the event loop itself. It works by 1412This benchmark actually benchmarks the event loop itself. It works by
1290creating a number of "servers": each server consists of a socketpair, a 1413creating a number of "servers": each server consists of a socket pair, a
1291timeout 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
1292watcher 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
1293watcher 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".
1294 1417
1295The 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
1296are 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
1297fds 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
1298timeout is reset each time something is read because that reflects how 1421timeout is reset each time something is read because that reflects how
1299most timeouts work (and puts extra pressure on the event loops). 1422most timeouts work (and puts extra pressure on the event loops).
1300 1423
1301In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 1424In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1302(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
1303connections, most of which are idle at any one point in time. 1426connections, most of which are idle at any one point in time.
1304 1427
1305Source 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
1306distribution. 1429distribution.
1308=head3 Explanation of the columns 1431=head3 Explanation of the columns
1309 1432
1310I<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
1311each server has a read and write socket end). 1434each server has a read and write socket end).
1312 1435
1313I<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
1314nontrivial) and two watchers: an I/O watcher and a timeout watcher. 1437nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1315 1438
1316I<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
1317single "request", that is, reading the token from the pipe and forwarding 1440single "request", that is, reading the token from the pipe and forwarding
1318it to another server. This includes deleting the old timeout and creating 1441it to another server. This includes deleting the old timeout and creating
1391speed 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
1392them). 1515them).
1393 1516
1394EV is again fastest. 1517EV is again fastest.
1395 1518
1396Perl 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
1397loops Event and Glib, although the difference is too small to really 1520loops Event and Glib, although the difference is too small to really
1398matter. 1521matter.
1399 1522
1400POE 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
1401others. 1524others.
1441probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1564probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1442 1565
1443 1566
1444=head1 SEE ALSO 1567=head1 SEE ALSO
1445 1568
1569Utility functions: L<AnyEvent::Util>.
1570
1446Event 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>,
1447L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 1572L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1448 1573
1449Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 1574Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1450L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 1575L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1451L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 1576L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1452L<AnyEvent::Impl::POE>. 1577L<AnyEvent::Impl::POE>.
1453 1578
1579Non-blocking file handles, sockets, TCP clients and
1580servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
1581
1582Asynchronous DNS: L<AnyEvent::DNS>.
1583
1454Coroutine 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>,
1455 1585
1456Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. 1586Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1457 1587
1458 1588
1459=head1 AUTHOR 1589=head1 AUTHOR
1460 1590
1461 Marc Lehmann <schmorp@schmorp.de> 1591 Marc Lehmann <schmorp@schmorp.de>

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