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Revision 1.112 by root, Sat May 10 01:04:42 2008 UTC vs.
Revision 1.134 by root, Sun May 25 04:44:04 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
513 524
514=head1 GLOBAL VARIABLES AND FUNCTIONS 525=head1 GLOBAL VARIABLES AND FUNCTIONS
582Be careful when you create watchers in the module body - AnyEvent will 593Be careful when you create watchers in the module body - AnyEvent will
583decide which event module to use as soon as the first method is called, so 594decide which event module to use as soon as the first method is called, so
584by calling AnyEvent in your module body you force the user of your module 595by calling AnyEvent in your module body you force the user of your module
585to load the event module first. 596to load the event module first.
586 597
587Never call C<< ->wait >> on a condition variable unless you I<know> that 598Never call C<< ->recv >> on a condition variable unless you I<know> that
588the C<< ->send >> method has been called on it already. This is 599the C<< ->send >> method has been called on it already. This is
589because it will stall the whole program, and the whole point of using 600because it will stall the whole program, and the whole point of using
590events is to stay interactive. 601events is to stay interactive.
591 602
592It is fine, however, to call C<< ->wait >> when the user of your module 603It is fine, however, to call C<< ->recv >> when the user of your module
593requests it (i.e. if you create a http request object ad have a method 604requests it (i.e. if you create a http request object ad have a method
594called C<results> that returns the results, it should call C<< ->wait >> 605called C<results> that returns the results, it should call C<< ->recv >>
595freely, as the user of your module knows what she is doing. always). 606freely, as the user of your module knows what she is doing. always).
596 607
597=head1 WHAT TO DO IN THE MAIN PROGRAM 608=head1 WHAT TO DO IN THE MAIN PROGRAM
598 609
599There will always be a single main program - the only place that should 610There will always be a single main program - the only place that should
601 612
602If it doesn't care, it can just "use AnyEvent" and use it itself, or not 613If it doesn't care, it can just "use AnyEvent" and use it itself, or not
603do anything special (it does not need to be event-based) and let AnyEvent 614do anything special (it does not need to be event-based) and let AnyEvent
604decide which implementation to chose if some module relies on it. 615decide which implementation to chose if some module relies on it.
605 616
606If the main program relies on a specific event model. For example, in 617If the main program relies on a specific event model - for example, in
607Gtk2 programs you have to rely on the Glib module. You should load the 618Gtk2 programs you have to rely on the Glib module - you should load the
608event module before loading AnyEvent or any module that uses it: generally 619event module before loading AnyEvent or any module that uses it: generally
609speaking, you should load it as early as possible. The reason is that 620speaking, you should load it as early as possible. The reason is that
610modules might create watchers when they are loaded, and AnyEvent will 621modules might create watchers when they are loaded, and AnyEvent will
611decide on the event model to use as soon as it creates watchers, and it 622decide on the event model to use as soon as it creates watchers, and it
612might chose the wrong one unless you load the correct one yourself. 623might chose the wrong one unless you load the correct one yourself.
613 624
614You can chose to use a rather inefficient pure-perl implementation by 625You can chose to use a pure-perl implementation by loading the
615loading the C<AnyEvent::Impl::Perl> module, which gives you similar 626C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
616behaviour everywhere, but letting AnyEvent chose is generally better. 627everywhere, but letting AnyEvent chose the model is generally better.
628
629=head2 MAINLOOP EMULATION
630
631Sometimes (often for short test scripts, or even standalone programs who
632only want to use AnyEvent), you do not want to run a specific event loop.
633
634In that case, you can use a condition variable like this:
635
636 AnyEvent->condvar->recv;
637
638This has the effect of entering the event loop and looping forever.
639
640Note that usually your program has some exit condition, in which case
641it is better to use the "traditional" approach of storing a condition
642variable somewhere, waiting for it, and sending it when the program should
643exit cleanly.
644
617 645
618=head1 OTHER MODULES 646=head1 OTHER MODULES
619 647
620The following is a non-exhaustive list of additional modules that use 648The following is a non-exhaustive list of additional modules that use
621AnyEvent and can therefore be mixed easily with other AnyEvent modules 649AnyEvent and can therefore be mixed easily with other AnyEvent modules
633 661
634Provide read and write buffers and manages watchers for reads and writes. 662Provide read and write buffers and manages watchers for reads and writes.
635 663
636=item L<AnyEvent::Socket> 664=item L<AnyEvent::Socket>
637 665
638Provides a means to do non-blocking connects, accepts etc. 666Provides various utility functions for (internet protocol) sockets,
667addresses and name resolution. Also functions to create non-blocking tcp
668connections or tcp servers, with IPv6 and SRV record support and more.
669
670=item L<AnyEvent::DNS>
671
672Provides rich asynchronous DNS resolver capabilities.
639 673
640=item L<AnyEvent::HTTPD> 674=item L<AnyEvent::HTTPD>
641 675
642Provides a simple web application server framework. 676Provides a simple web application server framework.
643
644=item L<AnyEvent::DNS>
645
646Provides asynchronous DNS resolver capabilities, beyond what
647L<AnyEvent::Util> offers.
648 677
649=item L<AnyEvent::FastPing> 678=item L<AnyEvent::FastPing>
650 679
651The fastest ping in the west. 680The fastest ping in the west.
652 681
669 698
670=item L<Coro> 699=item L<Coro>
671 700
672Has special support for AnyEvent via L<Coro::AnyEvent>. 701Has special support for AnyEvent via L<Coro::AnyEvent>.
673 702
703=item L<AnyEvent::AIO>, L<IO::AIO>
704
705Truly asynchronous I/O, should be in the toolbox of every event
706programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
707together.
708
709=item L<AnyEvent::BDB>, L<BDB>
710
711Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
712IO::AIO and AnyEvent together.
713
674=item L<IO::Lambda> 714=item L<IO::Lambda>
675 715
676The lambda approach to I/O - don't ask, look there. Can use AnyEvent. 716The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
677
678=item L<IO::AIO>
679
680Truly asynchronous I/O, should be in the toolbox of every event
681programmer. Can be trivially made to use AnyEvent.
682
683=item L<BDB>
684
685Truly asynchronous Berkeley DB access. Can be trivially made to use
686AnyEvent.
687 717
688=back 718=back
689 719
690=cut 720=cut
691 721
694no warnings; 724no warnings;
695use strict; 725use strict;
696 726
697use Carp; 727use Carp;
698 728
699our $VERSION = '3.4'; 729our $VERSION = '4.03';
700our $MODEL; 730our $MODEL;
701 731
702our $AUTOLOAD; 732our $AUTOLOAD;
703our @ISA; 733our @ISA;
704 734
705our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 735our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
706 736
707our @REGISTRY; 737our @REGISTRY;
738
739our %PROTOCOL; # (ipv4|ipv6) => (1|2)
740
741{
742 my $idx;
743 $PROTOCOL{$_} = ++$idx
744 for split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
745}
708 746
709my @models = ( 747my @models = (
710 [EV:: => AnyEvent::Impl::EV::], 748 [EV:: => AnyEvent::Impl::EV::],
711 [Event:: => AnyEvent::Impl::Event::], 749 [Event:: => AnyEvent::Impl::Event::],
712 [Tk:: => AnyEvent::Impl::Tk::], 750 [Tk:: => AnyEvent::Impl::Tk::],
733 1 771 1
734 } else { 772 } else {
735 push @post_detect, $cb; 773 push @post_detect, $cb;
736 774
737 defined wantarray 775 defined wantarray
738 ? bless \$cb, "AnyEvent::Util::Guard" 776 ? bless \$cb, "AnyEvent::Util::PostDetect"
739 : () 777 : ()
740 } 778 }
741} 779}
742 780
743sub AnyEvent::Util::Guard::DESTROY { 781sub AnyEvent::Util::PostDetect::DESTROY {
744 @post_detect = grep $_ != ${$_[0]}, @post_detect; 782 @post_detect = grep $_ != ${$_[0]}, @post_detect;
745} 783}
746 784
747sub detect() { 785sub detect() {
748 unless ($MODEL) { 786 unless ($MODEL) {
811 $class->$func (@_); 849 $class->$func (@_);
812} 850}
813 851
814package AnyEvent::Base; 852package AnyEvent::Base;
815 853
816# default implementation for ->condvar, ->wait, ->broadcast 854# default implementation for ->condvar
817 855
818sub condvar { 856sub condvar {
819 bless \my $flag, "AnyEvent::Base::CondVar" 857 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
820}
821
822sub AnyEvent::Base::CondVar::broadcast {
823 ${$_[0]}++;
824}
825
826sub AnyEvent::Base::CondVar::wait {
827 AnyEvent->one_event while !${$_[0]};
828} 858}
829 859
830# default implementation for ->signal 860# default implementation for ->signal
831 861
832our %SIG_CB; 862our %SIG_CB;
906 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 936 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
907 937
908 undef $CHLD_W unless keys %PID_CB; 938 undef $CHLD_W unless keys %PID_CB;
909} 939}
910 940
941package AnyEvent::CondVar;
942
943our @ISA = AnyEvent::CondVar::Base::;
944
945package AnyEvent::CondVar::Base;
946
947use overload
948 '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
949 fallback => 1;
950
951sub _send {
952 # nop
953}
954
955sub send {
956 my $cv = shift;
957 $cv->{_ae_sent} = [@_];
958 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
959 $cv->_send;
960}
961
962sub croak {
963 $_[0]{_ae_croak} = $_[1];
964 $_[0]->send;
965}
966
967sub ready {
968 $_[0]{_ae_sent}
969}
970
971sub _wait {
972 AnyEvent->one_event while !$_[0]{_ae_sent};
973}
974
975sub recv {
976 $_[0]->_wait;
977
978 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
979 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
980}
981
982sub cb {
983 $_[0]{_ae_cb} = $_[1] if @_ > 1;
984 $_[0]{_ae_cb}
985}
986
987sub begin {
988 ++$_[0]{_ae_counter};
989 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
990}
991
992sub end {
993 return if --$_[0]{_ae_counter};
994 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
995}
996
997# undocumented/compatibility with pre-3.4
998*broadcast = \&send;
999*wait = \&_wait;
1000
911=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1001=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
912 1002
913This is an advanced topic that you do not normally need to use AnyEvent in 1003This is an advanced topic that you do not normally need to use AnyEvent in
914a module. This section is only of use to event loop authors who want to 1004a module. This section is only of use to event loop authors who want to
915provide AnyEvent compatibility. 1005provide AnyEvent compatibility.
971model it chooses. 1061model it chooses.
972 1062
973=item C<PERL_ANYEVENT_MODEL> 1063=item C<PERL_ANYEVENT_MODEL>
974 1064
975This can be used to specify the event model to be used by AnyEvent, before 1065This can be used to specify the event model to be used by AnyEvent, before
976autodetection and -probing kicks in. It must be a string consisting 1066auto detection and -probing kicks in. It must be a string consisting
977entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 1067entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
978and the resulting module name is loaded and if the load was successful, 1068and the resulting module name is loaded and if the load was successful,
979used as event model. If it fails to load AnyEvent will proceed with 1069used as event model. If it fails to load AnyEvent will proceed with
980autodetection and -probing. 1070auto detection and -probing.
981 1071
982This functionality might change in future versions. 1072This functionality might change in future versions.
983 1073
984For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 1074For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
985could start your program like this: 1075could start your program like this:
986 1076
987 PERL_ANYEVENT_MODEL=Perl perl ... 1077 PERL_ANYEVENT_MODEL=Perl perl ...
1078
1079=item C<PERL_ANYEVENT_PROTOCOLS>
1080
1081Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1082for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1083of auto probing).
1084
1085Must be set to a comma-separated list of protocols or address families,
1086current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1087used, and preference will be given to protocols mentioned earlier in the
1088list.
1089
1090This variable can effectively be used for denial-of-service attacks
1091against local programs (e.g. when setuid), although the impact is likely
1092small, as the program has to handle connection errors already-
1093
1094Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1095but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1096- only support IPv4, never try to resolve or contact IPv6
1097addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1098IPv6, but prefer IPv6 over IPv4.
1099
1100=item C<PERL_ANYEVENT_EDNS0>
1101
1102Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1103for DNS. This extension is generally useful to reduce DNS traffic, but
1104some (broken) firewalls drop such DNS packets, which is why it is off by
1105default.
1106
1107Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1108EDNS0 in its DNS requests.
988 1109
989=back 1110=back
990 1111
991=head1 EXAMPLE PROGRAM 1112=head1 EXAMPLE PROGRAM
992 1113
1003 poll => 'r', 1124 poll => 'r',
1004 cb => sub { 1125 cb => sub {
1005 warn "io event <$_[0]>\n"; # will always output <r> 1126 warn "io event <$_[0]>\n"; # will always output <r>
1006 chomp (my $input = <STDIN>); # read a line 1127 chomp (my $input = <STDIN>); # read a line
1007 warn "read: $input\n"; # output what has been read 1128 warn "read: $input\n"; # output what has been read
1008 $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i 1129 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1009 }, 1130 },
1010 ); 1131 );
1011 1132
1012 my $time_watcher; # can only be used once 1133 my $time_watcher; # can only be used once
1013 1134
1018 }); 1139 });
1019 } 1140 }
1020 1141
1021 new_timer; # create first timer 1142 new_timer; # create first timer
1022 1143
1023 $cv->wait; # wait until user enters /^q/i 1144 $cv->recv; # wait until user enters /^q/i
1024 1145
1025=head1 REAL-WORLD EXAMPLE 1146=head1 REAL-WORLD EXAMPLE
1026 1147
1027Consider the L<Net::FCP> module. It features (among others) the following 1148Consider the L<Net::FCP> module. It features (among others) the following
1028API calls, which are to freenet what HTTP GET requests are to http: 1149API calls, which are to freenet what HTTP GET requests are to http:
1078 syswrite $txn->{fh}, $txn->{request} 1199 syswrite $txn->{fh}, $txn->{request}
1079 or die "connection or write error"; 1200 or die "connection or write error";
1080 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); 1201 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1081 1202
1082Again, C<fh_ready_r> waits till all data has arrived, and then stores the 1203Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1083result and signals any possible waiters that the request ahs finished: 1204result and signals any possible waiters that the request has finished:
1084 1205
1085 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; 1206 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1086 1207
1087 if (end-of-file or data complete) { 1208 if (end-of-file or data complete) {
1088 $txn->{result} = $txn->{buf}; 1209 $txn->{result} = $txn->{buf};
1089 $txn->{finished}->broadcast; 1210 $txn->{finished}->send;
1090 $txb->{cb}->($txn) of $txn->{cb}; # also call callback 1211 $txb->{cb}->($txn) of $txn->{cb}; # also call callback
1091 } 1212 }
1092 1213
1093The C<result> method, finally, just waits for the finished signal (if the 1214The C<result> method, finally, just waits for the finished signal (if the
1094request was already finished, it doesn't wait, of course, and returns the 1215request was already finished, it doesn't wait, of course, and returns the
1095data: 1216data:
1096 1217
1097 $txn->{finished}->wait; 1218 $txn->{finished}->recv;
1098 return $txn->{result}; 1219 return $txn->{result};
1099 1220
1100The actual code goes further and collects all errors (C<die>s, exceptions) 1221The actual code goes further and collects all errors (C<die>s, exceptions)
1101that occured during request processing. The C<result> method detects 1222that occurred during request processing. The C<result> method detects
1102whether an exception as thrown (it is stored inside the $txn object) 1223whether an exception as thrown (it is stored inside the $txn object)
1103and just throws the exception, which means connection errors and other 1224and just throws the exception, which means connection errors and other
1104problems get reported tot he code that tries to use the result, not in a 1225problems get reported tot he code that tries to use the result, not in a
1105random callback. 1226random callback.
1106 1227
1137 1258
1138 my $quit = AnyEvent->condvar; 1259 my $quit = AnyEvent->condvar;
1139 1260
1140 $fcp->txn_client_get ($url)->cb (sub { 1261 $fcp->txn_client_get ($url)->cb (sub {
1141 ... 1262 ...
1142 $quit->broadcast; 1263 $quit->send;
1143 }); 1264 });
1144 1265
1145 $quit->wait; 1266 $quit->recv;
1146 1267
1147 1268
1148=head1 BENCHMARKS 1269=head1 BENCHMARKS
1149 1270
1150To give you an idea of the performance and overheads that AnyEvent adds 1271To give you an idea of the performance and overheads that AnyEvent adds
1152of various event loops I prepared some benchmarks. 1273of various event loops I prepared some benchmarks.
1153 1274
1154=head2 BENCHMARKING ANYEVENT OVERHEAD 1275=head2 BENCHMARKING ANYEVENT OVERHEAD
1155 1276
1156Here is a benchmark of various supported event models used natively and 1277Here is a benchmark of various supported event models used natively and
1157through anyevent. The benchmark creates a lot of timers (with a zero 1278through AnyEvent. The benchmark creates a lot of timers (with a zero
1158timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 1279timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1159which it is), lets them fire exactly once and destroys them again. 1280which it is), lets them fire exactly once and destroys them again.
1160 1281
1161Source code for this benchmark is found as F<eg/bench> in the AnyEvent 1282Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1162distribution. 1283distribution.
1179all watchers, to avoid adding memory overhead. That means closure creation 1300all watchers, to avoid adding memory overhead. That means closure creation
1180and memory usage is not included in the figures. 1301and memory usage is not included in the figures.
1181 1302
1182I<invoke> is the time, in microseconds, used to invoke a simple 1303I<invoke> is the time, in microseconds, used to invoke a simple
1183callback. The callback simply counts down a Perl variable and after it was 1304callback. The callback simply counts down a Perl variable and after it was
1184invoked "watcher" times, it would C<< ->broadcast >> a condvar once to 1305invoked "watcher" times, it would C<< ->send >> a condvar once to
1185signal the end of this phase. 1306signal the end of this phase.
1186 1307
1187I<destroy> is the time, in microseconds, that it takes to destroy a single 1308I<destroy> is the time, in microseconds, that it takes to destroy a single
1188watcher. 1309watcher.
1189 1310
1285 1406
1286=back 1407=back
1287 1408
1288=head2 BENCHMARKING THE LARGE SERVER CASE 1409=head2 BENCHMARKING THE LARGE SERVER CASE
1289 1410
1290This benchmark atcually benchmarks the event loop itself. It works by 1411This benchmark actually benchmarks the event loop itself. It works by
1291creating a number of "servers": each server consists of a socketpair, a 1412creating a number of "servers": each server consists of a socket pair, a
1292timeout watcher that gets reset on activity (but never fires), and an I/O 1413timeout watcher that gets reset on activity (but never fires), and an I/O
1293watcher waiting for input on one side of the socket. Each time the socket 1414watcher waiting for input on one side of the socket. Each time the socket
1294watcher reads a byte it will write that byte to a random other "server". 1415watcher reads a byte it will write that byte to a random other "server".
1295 1416
1296The effect is that there will be a lot of I/O watchers, only part of which 1417The effect is that there will be a lot of I/O watchers, only part of which
1297are active at any one point (so there is a constant number of active 1418are active at any one point (so there is a constant number of active
1298fds for each loop iterstaion, but which fds these are is random). The 1419fds for each loop iteration, but which fds these are is random). The
1299timeout is reset each time something is read because that reflects how 1420timeout is reset each time something is read because that reflects how
1300most timeouts work (and puts extra pressure on the event loops). 1421most timeouts work (and puts extra pressure on the event loops).
1301 1422
1302In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 1423In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1303(1%) are active. This mirrors the activity of large servers with many 1424(1%) are active. This mirrors the activity of large servers with many
1304connections, most of which are idle at any one point in time. 1425connections, most of which are idle at any one point in time.
1305 1426
1306Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 1427Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1307distribution. 1428distribution.
1309=head3 Explanation of the columns 1430=head3 Explanation of the columns
1310 1431
1311I<sockets> is the number of sockets, and twice the number of "servers" (as 1432I<sockets> is the number of sockets, and twice the number of "servers" (as
1312each server has a read and write socket end). 1433each server has a read and write socket end).
1313 1434
1314I<create> is the time it takes to create a socketpair (which is 1435I<create> is the time it takes to create a socket pair (which is
1315nontrivial) and two watchers: an I/O watcher and a timeout watcher. 1436nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1316 1437
1317I<request>, the most important value, is the time it takes to handle a 1438I<request>, the most important value, is the time it takes to handle a
1318single "request", that is, reading the token from the pipe and forwarding 1439single "request", that is, reading the token from the pipe and forwarding
1319it to another server. This includes deleting the old timeout and creating 1440it to another server. This includes deleting the old timeout and creating
1392speed most when you have lots of watchers, not when you only have a few of 1513speed most when you have lots of watchers, not when you only have a few of
1393them). 1514them).
1394 1515
1395EV is again fastest. 1516EV is again fastest.
1396 1517
1397Perl again comes second. It is noticably faster than the C-based event 1518Perl again comes second. It is noticeably faster than the C-based event
1398loops Event and Glib, although the difference is too small to really 1519loops Event and Glib, although the difference is too small to really
1399matter. 1520matter.
1400 1521
1401POE also performs much better in this case, but is is still far behind the 1522POE also performs much better in this case, but is is still far behind the
1402others. 1523others.
1442probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1563probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1443 1564
1444 1565
1445=head1 SEE ALSO 1566=head1 SEE ALSO
1446 1567
1568Utility functions: L<AnyEvent::Util>.
1569
1447Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 1570Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1448L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 1571L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1449 1572
1450Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 1573Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1451L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 1574L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1452L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 1575L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1453L<AnyEvent::Impl::POE>. 1576L<AnyEvent::Impl::POE>.
1454 1577
1578Non-blocking file handles, sockets, TCP clients and
1579servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
1580
1581Asynchronous DNS: L<AnyEvent::DNS>.
1582
1455Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 1583Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1456 1584
1457Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. 1585Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1458 1586
1459 1587
1460=head1 AUTHOR 1588=head1 AUTHOR
1461 1589
1462 Marc Lehmann <schmorp@schmorp.de> 1590 Marc Lehmann <schmorp@schmorp.de>

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