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Revision 1.112 by root, Sat May 10 01:04:42 2008 UTC vs.
Revision 1.142 by root, Tue May 27 02:34:30 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?
48isn't itself. What's worse, all the potential users of your module are 48isn't itself. What's worse, all the potential users of your module are
49I<also> forced to use the same event loop you use. 49I<also> forced to use the same event loop you use.
50 50
51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52fine. AnyEvent + Tk works fine etc. etc. but none of these work together 52fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if 53with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54your module uses one of those, every user of your module has to use it, 54your module uses one of those, every user of your module has to use it,
55too. But if your module uses AnyEvent, it works transparently with all 55too. But if your module uses AnyEvent, it works transparently with all
56event models it supports (including stuff like POE and IO::Async, as long 56event models it supports (including stuff like POE and IO::Async, as long
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, AnyEvent comes with a big (and fully optional!) toolbox
68of useful functionality, such as an asynchronous DNS resolver, 100%
69non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
70such as Windows) and lots of real-world knowledge and workarounds for
71platform bugs and differences.
72
67Of course, if you want lots of policy (this can arguably be somewhat 73Now, if you I<do want> lots of policy (this can arguably be somewhat
68useful) and you want to force your users to use the one and only event 74useful) and you want to force your users to use the one and only event
69model, you should I<not> use this module. 75model, you should I<not> use this module.
70 76
71=head1 DESCRIPTION 77=head1 DESCRIPTION
72 78
102starts using it, all bets are off. Maybe you should tell their authors to 108starts using it, all bets are off. Maybe you should tell their authors to
103use AnyEvent so their modules work together with others seamlessly... 109use AnyEvent so their modules work together with others seamlessly...
104 110
105The pure-perl implementation of AnyEvent is called 111The pure-perl implementation of AnyEvent is called
106C<AnyEvent::Impl::Perl>. Like other event modules you can load it 112C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107explicitly. 113explicitly and enjoy the high availability of that event loop :)
108 114
109=head1 WATCHERS 115=head1 WATCHERS
110 116
111AnyEvent has the central concept of a I<watcher>, which is an object that 117AnyEvent 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 118stores relevant data for each kind of event you are waiting for, such as
113the callback to call, the filehandle to watch, etc. 119the callback to call, the file handle to watch, etc.
114 120
115These watchers are normal Perl objects with normal Perl lifetime. After 121These watchers are normal Perl objects with normal Perl lifetime. After
116creating a watcher it will immediately "watch" for events and invoke the 122creating a watcher it will immediately "watch" for events and invoke the
117callback when the event occurs (of course, only when the event model 123callback when the event occurs (of course, only when the event model
118is in control). 124is in control).
237 243
238Although the callback might get passed parameters, their value and 244Although the callback might get passed parameters, their value and
239presence is undefined and you cannot rely on them. Portable AnyEvent 245presence is undefined and you cannot rely on them. Portable AnyEvent
240callbacks cannot use arguments passed to signal watcher callbacks. 246callbacks cannot use arguments passed to signal watcher callbacks.
241 247
242Multiple signal occurances can be clumped together into one callback 248Multiple signal occurrences can be clumped together into one callback
243invocation, and callback invocation will be synchronous. synchronous means 249invocation, and callback invocation will be synchronous. Synchronous means
244that it might take a while until the signal gets handled by the process, 250that it might take a while until the signal gets handled by the process,
245but it is guarenteed not to interrupt any other callbacks. 251but it is guaranteed not to interrupt any other callbacks.
246 252
247The main advantage of using these watchers is that you can share a signal 253The main advantage of using these watchers is that you can share a signal
248between multiple watchers. 254between multiple watchers.
249 255
250This watcher might use C<%SIG>, so programs overwriting those signals 256This watcher might use C<%SIG>, so programs overwriting those signals
278C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 284C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279 285
280Example: fork a process and wait for it 286Example: fork a process and wait for it
281 287
282 my $done = AnyEvent->condvar; 288 my $done = AnyEvent->condvar;
283
284 AnyEvent::detect; # force event module to be initialised
285 289
286 my $pid = fork or exit 5; 290 my $pid = fork or exit 5;
287 291
288 my $w = AnyEvent->child ( 292 my $w = AnyEvent->child (
289 pid => $pid, 293 pid => $pid,
293 $done->send; 297 $done->send;
294 }, 298 },
295 ); 299 );
296 300
297 # do something else, then wait for process exit 301 # do something else, then wait for process exit
298 $done->wait; 302 $done->recv;
299 303
300=head2 CONDITION VARIABLES 304=head2 CONDITION VARIABLES
301 305
302If you are familiar with some event loops you will know that all of them 306If 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 307require you to run some blocking "loop", "run" or similar function that
312Condition variables can be created by calling the C<< AnyEvent->condvar 316Condition variables can be created by calling the C<< AnyEvent->condvar
313>> method, usually without arguments. The only argument pair allowed is 317>> method, usually without arguments. The only argument pair allowed is
314C<cb>, which specifies a callback to be called when the condition variable 318C<cb>, which specifies a callback to be called when the condition variable
315becomes true. 319becomes true.
316 320
317After creation, the conditon variable is "false" until it becomes "true" 321After creation, the condition variable is "false" until it becomes "true"
318by calling the C<send> method. 322by calling the C<send> method (or calling the condition variable as if it
323were a callback, read about the caveats in the description for the C<<
324->send >> method).
319 325
320Condition variables are similar to callbacks, except that you can 326Condition variables are similar to callbacks, except that you can
321optionally wait for them. They can also be called merge points - points 327optionally wait for them. They can also be called merge points - points
322in time where multiple outstandign events have been processed. And yet 328in time where multiple outstanding events have been processed. And yet
323another way to call them is transations - each condition variable can be 329another way to call them is transactions - each condition variable can be
324used to represent a transaction, which finishes at some point and delivers 330used to represent a transaction, which finishes at some point and delivers
325a result. 331a result.
326 332
327Condition variables are very useful to signal that something has finished, 333Condition variables are very useful to signal that something has finished,
328for example, if you write a module that does asynchronous http requests, 334for example, if you write a module that does asynchronous http requests,
329then a condition variable would be the ideal candidate to signal the 335then a condition variable would be the ideal candidate to signal the
330availability of results. The user can either act when the callback is 336availability of results. The user can either act when the callback is
331called or can synchronously C<< ->wait >> for the results. 337called or can synchronously C<< ->recv >> for the results.
332 338
333You can also use them to simulate traditional event loops - for example, 339You can also use them to simulate traditional event loops - for example,
334you can block your main program until an event occurs - for example, you 340you 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 341could C<< ->recv >> in your main program until the user clicks the Quit
336button of your app, which would C<< ->send >> the "quit" event. 342button of your app, which would C<< ->send >> the "quit" event.
337 343
338Note that condition variables recurse into the event loop - if you have 344Note 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 345two 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 346lose. Therefore, condition variables are good to export to your caller, but
341you should avoid making a blocking wait yourself, at least in callbacks, 347you should avoid making a blocking wait yourself, at least in callbacks,
342as this asks for trouble. 348as this asks for trouble.
343 349
344Condition variables are represented by hash refs in perl, and the keys 350Condition variables are represented by hash refs in perl, and the keys
349 355
350There are two "sides" to a condition variable - the "producer side" which 356There are two "sides" to a condition variable - the "producer side" which
351eventually calls C<< -> send >>, and the "consumer side", which waits 357eventually calls C<< -> send >>, and the "consumer side", which waits
352for the send to occur. 358for the send to occur.
353 359
354Example: 360Example: wait for a timer.
355 361
356 # wait till the result is ready 362 # wait till the result is ready
357 my $result_ready = AnyEvent->condvar; 363 my $result_ready = AnyEvent->condvar;
358 364
359 # do something such as adding a timer 365 # do something such as adding a timer
365 cb => sub { $result_ready->send }, 371 cb => sub { $result_ready->send },
366 ); 372 );
367 373
368 # this "blocks" (while handling events) till the callback 374 # this "blocks" (while handling events) till the callback
369 # calls send 375 # calls send
370 $result_ready->wait; 376 $result_ready->recv;
377
378Example: wait for a timer, but take advantage of the fact that
379condition variables are also code references.
380
381 my $done = AnyEvent->condvar;
382 my $delay = AnyEvent->timer (after => 5, cb => $done);
383 $done->recv;
371 384
372=head3 METHODS FOR PRODUCERS 385=head3 METHODS FOR PRODUCERS
373 386
374These methods should only be used by the producing side, i.e. the 387These methods should only be used by the producing side, i.e. the
375code/module that eventually sends the signal. Note that it is also 388code/module that eventually sends the signal. Note that it is also
378 391
379=over 4 392=over 4
380 393
381=item $cv->send (...) 394=item $cv->send (...)
382 395
383Flag the condition as ready - a running C<< ->wait >> and all further 396Flag the condition as ready - a running C<< ->recv >> and all further
384calls to C<wait> will (eventually) return after this method has been 397calls to C<recv> will (eventually) return after this method has been
385called. If nobody is waiting the send will be remembered. 398called. If nobody is waiting the send will be remembered.
386 399
387If a callback has been set on the condition variable, it is called 400If a callback has been set on the condition variable, it is called
388immediately from within send. 401immediately from within send.
389 402
390Any arguments passed to the C<send> call will be returned by all 403Any arguments passed to the C<send> call will be returned by all
391future C<< ->wait >> calls. 404future C<< ->recv >> calls.
405
406Condition variables are overloaded so one can call them directly
407(as a code reference). Calling them directly is the same as calling
408C<send>. Note, however, that many C-based event loops do not handle
409overloading, so as tempting as it may be, passing a condition variable
410instead of a callback does not work. Both the pure perl and EV loops
411support overloading, however, as well as all functions that use perl to
412invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
413example).
392 414
393=item $cv->croak ($error) 415=item $cv->croak ($error)
394 416
395Similar to send, but causes all call's wait C<< ->wait >> to invoke 417Similar to send, but causes all call's to C<< ->recv >> to invoke
396C<Carp::croak> with the given error message/object/scalar. 418C<Carp::croak> with the given error message/object/scalar.
397 419
398This can be used to signal any errors to the condition variable 420This can be used to signal any errors to the condition variable
399user/consumer. 421user/consumer.
400 422
401=item $cv->begin ([group callback]) 423=item $cv->begin ([group callback])
402 424
403=item $cv->end 425=item $cv->end
426
427These two methods are EXPERIMENTAL and MIGHT CHANGE.
404 428
405These two methods can be used to combine many transactions/events into 429These two methods can be used to combine many transactions/events into
406one. For example, a function that pings many hosts in parallel might want 430one. For example, a function that pings many hosts in parallel might want
407to use a condition variable for the whole process. 431to use a condition variable for the whole process.
408 432
443doesn't execute once). 467doesn't execute once).
444 468
445This is the general pattern when you "fan out" into multiple subrequests: 469This 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> 470use 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 471is called at least once, and then, for each subrequest you start, call
448C<begin> and for eahc subrequest you finish, call C<end>. 472C<begin> and for each subrequest you finish, call C<end>.
449 473
450=back 474=back
451 475
452=head3 METHODS FOR CONSUMERS 476=head3 METHODS FOR CONSUMERS
453 477
454These methods should only be used by the consuming side, i.e. the 478These methods should only be used by the consuming side, i.e. the
455code awaits the condition. 479code awaits the condition.
456 480
457=over 4 481=over 4
458 482
459=item $cv->wait 483=item $cv->recv
460 484
461Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak 485Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462>> methods have been called on c<$cv>, while servicing other watchers 486>> methods have been called on c<$cv>, while servicing other watchers
463normally. 487normally.
464 488
475(programs might want to do that to stay interactive), so I<if you are 499(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 500using 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 501caller decide whether the call will block or not (for example, by coupling
478condition variables with some kind of request results and supporting 502condition variables with some kind of request results and supporting
479callbacks so the caller knows that getting the result will not block, 503callbacks so the caller knows that getting the result will not block,
480while still suppporting blocking waits if the caller so desires). 504while still supporting blocking waits if the caller so desires).
481 505
482Another reason I<never> to C<< ->wait >> in a module is that you cannot 506Another 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 507sensibly have two C<< ->recv >>'s in parallel, as that would require
484multiple interpreters or coroutines/threads, none of which C<AnyEvent> 508multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485can supply. 509can supply.
486 510
487The L<Coro> module, however, I<can> and I<does> supply coroutines and, in 511The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
488fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe 512fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
489versions and also integrates coroutines into AnyEvent, making blocking 513versions and also integrates coroutines into AnyEvent, making blocking
490C<< ->wait >> calls perfectly safe as long as they are done from another 514C<< ->recv >> calls perfectly safe as long as they are done from another
491coroutine (one that doesn't run the event loop). 515coroutine (one that doesn't run the event loop).
492 516
493You can ensure that C<< -wait >> never blocks by setting a callback and 517You can ensure that C<< -recv >> never blocks by setting a callback and
494only calling C<< ->wait >> from within that callback (or at a later 518only calling C<< ->recv >> from within that callback (or at a later
495time). This will work even when the event loop does not support blocking 519time). This will work even when the event loop does not support blocking
496waits otherwise. 520waits otherwise.
497 521
498=item $bool = $cv->ready 522=item $bool = $cv->ready
499 523
504 528
505This is a mutator function that returns the callback set and optionally 529This is a mutator function that returns the callback set and optionally
506replaces it before doing so. 530replaces it before doing so.
507 531
508The callback will be called when the condition becomes "true", i.e. when 532The 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 533C<send> or C<croak> are called. Calling C<recv> inside the callback
510or at any later time is guaranteed not to block. 534or at any later time is guaranteed not to block.
511 535
512=back 536=back
513 537
514=head1 GLOBAL VARIABLES AND FUNCTIONS 538=head1 GLOBAL VARIABLES AND FUNCTIONS
582Be careful when you create watchers in the module body - AnyEvent will 606Be 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 607decide 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 608by calling AnyEvent in your module body you force the user of your module
585to load the event module first. 609to load the event module first.
586 610
587Never call C<< ->wait >> on a condition variable unless you I<know> that 611Never call C<< ->recv >> on a condition variable unless you I<know> that
588the C<< ->send >> method has been called on it already. This is 612the C<< ->send >> method has been called on it already. This is
589because it will stall the whole program, and the whole point of using 613because it will stall the whole program, and the whole point of using
590events is to stay interactive. 614events is to stay interactive.
591 615
592It is fine, however, to call C<< ->wait >> when the user of your module 616It 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 617requests 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 >> 618called C<results> that returns the results, it should call C<< ->recv >>
595freely, as the user of your module knows what she is doing. always). 619freely, as the user of your module knows what she is doing. always).
596 620
597=head1 WHAT TO DO IN THE MAIN PROGRAM 621=head1 WHAT TO DO IN THE MAIN PROGRAM
598 622
599There will always be a single main program - the only place that should 623There will always be a single main program - the only place that should
601 625
602If it doesn't care, it can just "use AnyEvent" and use it itself, or not 626If 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 627do anything special (it does not need to be event-based) and let AnyEvent
604decide which implementation to chose if some module relies on it. 628decide which implementation to chose if some module relies on it.
605 629
606If the main program relies on a specific event model. For example, in 630If 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 631Gtk2 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 632event module before loading AnyEvent or any module that uses it: generally
609speaking, you should load it as early as possible. The reason is that 633speaking, you should load it as early as possible. The reason is that
610modules might create watchers when they are loaded, and AnyEvent will 634modules 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 635decide 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. 636might chose the wrong one unless you load the correct one yourself.
613 637
614You can chose to use a rather inefficient pure-perl implementation by 638You can chose to use a pure-perl implementation by loading the
615loading the C<AnyEvent::Impl::Perl> module, which gives you similar 639C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
616behaviour everywhere, but letting AnyEvent chose is generally better. 640everywhere, but letting AnyEvent chose the model is generally better.
641
642=head2 MAINLOOP EMULATION
643
644Sometimes (often for short test scripts, or even standalone programs who
645only want to use AnyEvent), you do not want to run a specific event loop.
646
647In that case, you can use a condition variable like this:
648
649 AnyEvent->condvar->recv;
650
651This has the effect of entering the event loop and looping forever.
652
653Note that usually your program has some exit condition, in which case
654it is better to use the "traditional" approach of storing a condition
655variable somewhere, waiting for it, and sending it when the program should
656exit cleanly.
657
617 658
618=head1 OTHER MODULES 659=head1 OTHER MODULES
619 660
620The following is a non-exhaustive list of additional modules that use 661The following is a non-exhaustive list of additional modules that use
621AnyEvent and can therefore be mixed easily with other AnyEvent modules 662AnyEvent and can therefore be mixed easily with other AnyEvent modules
633 674
634Provide read and write buffers and manages watchers for reads and writes. 675Provide read and write buffers and manages watchers for reads and writes.
635 676
636=item L<AnyEvent::Socket> 677=item L<AnyEvent::Socket>
637 678
638Provides a means to do non-blocking connects, accepts etc. 679Provides various utility functions for (internet protocol) sockets,
680addresses and name resolution. Also functions to create non-blocking tcp
681connections or tcp servers, with IPv6 and SRV record support and more.
682
683=item L<AnyEvent::DNS>
684
685Provides rich asynchronous DNS resolver capabilities.
639 686
640=item L<AnyEvent::HTTPD> 687=item L<AnyEvent::HTTPD>
641 688
642Provides a simple web application server framework. 689Provides a simple web application server framework.
643
644=item L<AnyEvent::DNS>
645
646Provides asynchronous DNS resolver capabilities, beyond what
647L<AnyEvent::Util> offers.
648 690
649=item L<AnyEvent::FastPing> 691=item L<AnyEvent::FastPing>
650 692
651The fastest ping in the west. 693The fastest ping in the west.
652 694
669 711
670=item L<Coro> 712=item L<Coro>
671 713
672Has special support for AnyEvent via L<Coro::AnyEvent>. 714Has special support for AnyEvent via L<Coro::AnyEvent>.
673 715
716=item L<AnyEvent::AIO>, L<IO::AIO>
717
718Truly asynchronous I/O, should be in the toolbox of every event
719programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
720together.
721
722=item L<AnyEvent::BDB>, L<BDB>
723
724Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
725IO::AIO and AnyEvent together.
726
674=item L<IO::Lambda> 727=item L<IO::Lambda>
675 728
676The lambda approach to I/O - don't ask, look there. Can use AnyEvent. 729The 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.
687 730
688=back 731=back
689 732
690=cut 733=cut
691 734
694no warnings; 737no warnings;
695use strict; 738use strict;
696 739
697use Carp; 740use Carp;
698 741
699our $VERSION = '3.4'; 742our $VERSION = '4.05';
700our $MODEL; 743our $MODEL;
701 744
702our $AUTOLOAD; 745our $AUTOLOAD;
703our @ISA; 746our @ISA;
704 747
748our @REGISTRY;
749
750our $WIN32;
751
752BEGIN {
753 my $win32 = ! ! ($^O =~ /mswin32/i);
754 eval "sub WIN32(){ $win32 }";
755}
756
705our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 757our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
706 758
707our @REGISTRY; 759our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
760
761{
762 my $idx;
763 $PROTOCOL{$_} = ++$idx
764 for reverse split /\s*,\s*/,
765 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
766}
708 767
709my @models = ( 768my @models = (
710 [EV:: => AnyEvent::Impl::EV::], 769 [EV:: => AnyEvent::Impl::EV::],
711 [Event:: => AnyEvent::Impl::Event::], 770 [Event:: => AnyEvent::Impl::Event::],
712 [Tk:: => AnyEvent::Impl::Tk::],
713 [Wx:: => AnyEvent::Impl::POE::],
714 [Prima:: => AnyEvent::Impl::POE::],
715 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 771 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
716 # everything below here will not be autoprobed as the pureperl backend should work everywhere 772 # everything below here will not be autoprobed
717 [Glib:: => AnyEvent::Impl::Glib::], 773 # as the pureperl backend should work everywhere
774 # and is usually faster
775 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
776 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
718 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 777 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
719 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 778 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
720 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 779 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
780 [Wx:: => AnyEvent::Impl::POE::],
781 [Prima:: => AnyEvent::Impl::POE::],
721); 782);
722 783
723our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); 784our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
724 785
725our @post_detect; 786our @post_detect;
733 1 794 1
734 } else { 795 } else {
735 push @post_detect, $cb; 796 push @post_detect, $cb;
736 797
737 defined wantarray 798 defined wantarray
738 ? bless \$cb, "AnyEvent::Util::Guard" 799 ? bless \$cb, "AnyEvent::Util::PostDetect"
739 : () 800 : ()
740 } 801 }
741} 802}
742 803
743sub AnyEvent::Util::Guard::DESTROY { 804sub AnyEvent::Util::PostDetect::DESTROY {
744 @post_detect = grep $_ != ${$_[0]}, @post_detect; 805 @post_detect = grep $_ != ${$_[0]}, @post_detect;
745} 806}
746 807
747sub detect() { 808sub detect() {
748 unless ($MODEL) { 809 unless ($MODEL) {
749 no strict 'refs'; 810 no strict 'refs';
811 local $SIG{__DIE__};
750 812
751 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 813 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
752 my $model = "AnyEvent::Impl::$1"; 814 my $model = "AnyEvent::Impl::$1";
753 if (eval "require $model") { 815 if (eval "require $model") {
754 $MODEL = $model; 816 $MODEL = $model;
811 $class->$func (@_); 873 $class->$func (@_);
812} 874}
813 875
814package AnyEvent::Base; 876package AnyEvent::Base;
815 877
816# default implementation for ->condvar, ->wait, ->broadcast 878# default implementation for ->condvar
817 879
818sub condvar { 880sub condvar {
819 bless \my $flag, "AnyEvent::Base::CondVar" 881 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} 882}
829 883
830# default implementation for ->signal 884# default implementation for ->signal
831 885
832our %SIG_CB; 886our %SIG_CB;
885 or Carp::croak "required option 'pid' is missing"; 939 or Carp::croak "required option 'pid' is missing";
886 940
887 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 941 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
888 942
889 unless ($WNOHANG) { 943 unless ($WNOHANG) {
890 $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; 944 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
891 } 945 }
892 946
893 unless ($CHLD_W) { 947 unless ($CHLD_W) {
894 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 948 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
895 # child could be a zombie already, so make at least one round 949 # child could be a zombie already, so make at least one round
905 delete $PID_CB{$pid}{$cb}; 959 delete $PID_CB{$pid}{$cb};
906 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 960 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
907 961
908 undef $CHLD_W unless keys %PID_CB; 962 undef $CHLD_W unless keys %PID_CB;
909} 963}
964
965package AnyEvent::CondVar;
966
967our @ISA = AnyEvent::CondVar::Base::;
968
969package AnyEvent::CondVar::Base;
970
971use overload
972 '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
973 fallback => 1;
974
975sub _send {
976 # nop
977}
978
979sub send {
980 my $cv = shift;
981 $cv->{_ae_sent} = [@_];
982 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
983 $cv->_send;
984}
985
986sub croak {
987 $_[0]{_ae_croak} = $_[1];
988 $_[0]->send;
989}
990
991sub ready {
992 $_[0]{_ae_sent}
993}
994
995sub _wait {
996 AnyEvent->one_event while !$_[0]{_ae_sent};
997}
998
999sub recv {
1000 $_[0]->_wait;
1001
1002 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1003 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1004}
1005
1006sub cb {
1007 $_[0]{_ae_cb} = $_[1] if @_ > 1;
1008 $_[0]{_ae_cb}
1009}
1010
1011sub begin {
1012 ++$_[0]{_ae_counter};
1013 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1014}
1015
1016sub end {
1017 return if --$_[0]{_ae_counter};
1018 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1019}
1020
1021# undocumented/compatibility with pre-3.4
1022*broadcast = \&send;
1023*wait = \&_wait;
910 1024
911=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1025=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
912 1026
913This is an advanced topic that you do not normally need to use AnyEvent in 1027This 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 1028a module. This section is only of use to event loop authors who want to
971model it chooses. 1085model it chooses.
972 1086
973=item C<PERL_ANYEVENT_MODEL> 1087=item C<PERL_ANYEVENT_MODEL>
974 1088
975This can be used to specify the event model to be used by AnyEvent, before 1089This 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 1090auto detection and -probing kicks in. It must be a string consisting
977entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 1091entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
978and the resulting module name is loaded and if the load was successful, 1092and 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 1093used as event model. If it fails to load AnyEvent will proceed with
980autodetection and -probing. 1094auto detection and -probing.
981 1095
982This functionality might change in future versions. 1096This functionality might change in future versions.
983 1097
984For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 1098For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
985could start your program like this: 1099could start your program like this:
986 1100
987 PERL_ANYEVENT_MODEL=Perl perl ... 1101 PERL_ANYEVENT_MODEL=Perl perl ...
1102
1103=item C<PERL_ANYEVENT_PROTOCOLS>
1104
1105Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1106for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1107of auto probing).
1108
1109Must be set to a comma-separated list of protocols or address families,
1110current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1111used, and preference will be given to protocols mentioned earlier in the
1112list.
1113
1114This variable can effectively be used for denial-of-service attacks
1115against local programs (e.g. when setuid), although the impact is likely
1116small, as the program has to handle connection errors already-
1117
1118Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1119but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1120- only support IPv4, never try to resolve or contact IPv6
1121addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1122IPv6, but prefer IPv6 over IPv4.
1123
1124=item C<PERL_ANYEVENT_EDNS0>
1125
1126Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1127for DNS. This extension is generally useful to reduce DNS traffic, but
1128some (broken) firewalls drop such DNS packets, which is why it is off by
1129default.
1130
1131Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1132EDNS0 in its DNS requests.
1133
1134=item C<PERL_ANYEVENT_MAX_FORKS>
1135
1136The maximum number of child processes that C<AnyEvent::Util::fork_call>
1137will create in parallel.
988 1138
989=back 1139=back
990 1140
991=head1 EXAMPLE PROGRAM 1141=head1 EXAMPLE PROGRAM
992 1142
1003 poll => 'r', 1153 poll => 'r',
1004 cb => sub { 1154 cb => sub {
1005 warn "io event <$_[0]>\n"; # will always output <r> 1155 warn "io event <$_[0]>\n"; # will always output <r>
1006 chomp (my $input = <STDIN>); # read a line 1156 chomp (my $input = <STDIN>); # read a line
1007 warn "read: $input\n"; # output what has been read 1157 warn "read: $input\n"; # output what has been read
1008 $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i 1158 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1009 }, 1159 },
1010 ); 1160 );
1011 1161
1012 my $time_watcher; # can only be used once 1162 my $time_watcher; # can only be used once
1013 1163
1018 }); 1168 });
1019 } 1169 }
1020 1170
1021 new_timer; # create first timer 1171 new_timer; # create first timer
1022 1172
1023 $cv->wait; # wait until user enters /^q/i 1173 $cv->recv; # wait until user enters /^q/i
1024 1174
1025=head1 REAL-WORLD EXAMPLE 1175=head1 REAL-WORLD EXAMPLE
1026 1176
1027Consider the L<Net::FCP> module. It features (among others) the following 1177Consider the L<Net::FCP> module. It features (among others) the following
1028API calls, which are to freenet what HTTP GET requests are to http: 1178API calls, which are to freenet what HTTP GET requests are to http:
1078 syswrite $txn->{fh}, $txn->{request} 1228 syswrite $txn->{fh}, $txn->{request}
1079 or die "connection or write error"; 1229 or die "connection or write error";
1080 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); 1230 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1081 1231
1082Again, C<fh_ready_r> waits till all data has arrived, and then stores the 1232Again, 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: 1233result and signals any possible waiters that the request has finished:
1084 1234
1085 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; 1235 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1086 1236
1087 if (end-of-file or data complete) { 1237 if (end-of-file or data complete) {
1088 $txn->{result} = $txn->{buf}; 1238 $txn->{result} = $txn->{buf};
1089 $txn->{finished}->broadcast; 1239 $txn->{finished}->send;
1090 $txb->{cb}->($txn) of $txn->{cb}; # also call callback 1240 $txb->{cb}->($txn) of $txn->{cb}; # also call callback
1091 } 1241 }
1092 1242
1093The C<result> method, finally, just waits for the finished signal (if the 1243The 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 1244request was already finished, it doesn't wait, of course, and returns the
1095data: 1245data:
1096 1246
1097 $txn->{finished}->wait; 1247 $txn->{finished}->recv;
1098 return $txn->{result}; 1248 return $txn->{result};
1099 1249
1100The actual code goes further and collects all errors (C<die>s, exceptions) 1250The actual code goes further and collects all errors (C<die>s, exceptions)
1101that occured during request processing. The C<result> method detects 1251that occurred during request processing. The C<result> method detects
1102whether an exception as thrown (it is stored inside the $txn object) 1252whether an exception as thrown (it is stored inside the $txn object)
1103and just throws the exception, which means connection errors and other 1253and 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 1254problems get reported tot he code that tries to use the result, not in a
1105random callback. 1255random callback.
1106 1256
1137 1287
1138 my $quit = AnyEvent->condvar; 1288 my $quit = AnyEvent->condvar;
1139 1289
1140 $fcp->txn_client_get ($url)->cb (sub { 1290 $fcp->txn_client_get ($url)->cb (sub {
1141 ... 1291 ...
1142 $quit->broadcast; 1292 $quit->send;
1143 }); 1293 });
1144 1294
1145 $quit->wait; 1295 $quit->recv;
1146 1296
1147 1297
1148=head1 BENCHMARKS 1298=head1 BENCHMARKS
1149 1299
1150To give you an idea of the performance and overheads that AnyEvent adds 1300To give you an idea of the performance and overheads that AnyEvent adds
1152of various event loops I prepared some benchmarks. 1302of various event loops I prepared some benchmarks.
1153 1303
1154=head2 BENCHMARKING ANYEVENT OVERHEAD 1304=head2 BENCHMARKING ANYEVENT OVERHEAD
1155 1305
1156Here is a benchmark of various supported event models used natively and 1306Here is a benchmark of various supported event models used natively and
1157through anyevent. The benchmark creates a lot of timers (with a zero 1307through AnyEvent. The benchmark creates a lot of timers (with a zero
1158timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 1308timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1159which it is), lets them fire exactly once and destroys them again. 1309which it is), lets them fire exactly once and destroys them again.
1160 1310
1161Source code for this benchmark is found as F<eg/bench> in the AnyEvent 1311Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1162distribution. 1312distribution.
1179all watchers, to avoid adding memory overhead. That means closure creation 1329all watchers, to avoid adding memory overhead. That means closure creation
1180and memory usage is not included in the figures. 1330and memory usage is not included in the figures.
1181 1331
1182I<invoke> is the time, in microseconds, used to invoke a simple 1332I<invoke> is the time, in microseconds, used to invoke a simple
1183callback. The callback simply counts down a Perl variable and after it was 1333callback. The callback simply counts down a Perl variable and after it was
1184invoked "watcher" times, it would C<< ->broadcast >> a condvar once to 1334invoked "watcher" times, it would C<< ->send >> a condvar once to
1185signal the end of this phase. 1335signal the end of this phase.
1186 1336
1187I<destroy> is the time, in microseconds, that it takes to destroy a single 1337I<destroy> is the time, in microseconds, that it takes to destroy a single
1188watcher. 1338watcher.
1189 1339
1285 1435
1286=back 1436=back
1287 1437
1288=head2 BENCHMARKING THE LARGE SERVER CASE 1438=head2 BENCHMARKING THE LARGE SERVER CASE
1289 1439
1290This benchmark atcually benchmarks the event loop itself. It works by 1440This benchmark actually benchmarks the event loop itself. It works by
1291creating a number of "servers": each server consists of a socketpair, a 1441creating 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 1442timeout 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 1443watcher 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". 1444watcher reads a byte it will write that byte to a random other "server".
1295 1445
1296The effect is that there will be a lot of I/O watchers, only part of which 1446The 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 1447are 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 1448fds for each loop iteration, but which fds these are is random). The
1299timeout is reset each time something is read because that reflects how 1449timeout is reset each time something is read because that reflects how
1300most timeouts work (and puts extra pressure on the event loops). 1450most timeouts work (and puts extra pressure on the event loops).
1301 1451
1302In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 1452In 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 1453(1%) are active. This mirrors the activity of large servers with many
1304connections, most of which are idle at any one point in time. 1454connections, most of which are idle at any one point in time.
1305 1455
1306Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 1456Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1307distribution. 1457distribution.
1309=head3 Explanation of the columns 1459=head3 Explanation of the columns
1310 1460
1311I<sockets> is the number of sockets, and twice the number of "servers" (as 1461I<sockets> is the number of sockets, and twice the number of "servers" (as
1312each server has a read and write socket end). 1462each server has a read and write socket end).
1313 1463
1314I<create> is the time it takes to create a socketpair (which is 1464I<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. 1465nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1316 1466
1317I<request>, the most important value, is the time it takes to handle a 1467I<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 1468single "request", that is, reading the token from the pipe and forwarding
1319it to another server. This includes deleting the old timeout and creating 1469it 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 1542speed most when you have lots of watchers, not when you only have a few of
1393them). 1543them).
1394 1544
1395EV is again fastest. 1545EV is again fastest.
1396 1546
1397Perl again comes second. It is noticably faster than the C-based event 1547Perl again comes second. It is noticeably faster than the C-based event
1398loops Event and Glib, although the difference is too small to really 1548loops Event and Glib, although the difference is too small to really
1399matter. 1549matter.
1400 1550
1401POE also performs much better in this case, but is is still far behind the 1551POE also performs much better in this case, but is is still far behind the
1402others. 1552others.
1442probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1592probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1443 1593
1444 1594
1445=head1 SEE ALSO 1595=head1 SEE ALSO
1446 1596
1597Utility functions: L<AnyEvent::Util>.
1598
1447Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 1599Event 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>. 1600L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1449 1601
1450Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 1602Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1451L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 1603L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1452L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 1604L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1453L<AnyEvent::Impl::POE>. 1605L<AnyEvent::Impl::POE>.
1454 1606
1607Non-blocking file handles, sockets, TCP clients and
1608servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
1609
1610Asynchronous DNS: L<AnyEvent::DNS>.
1611
1455Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 1612Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1456 1613
1457Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. 1614Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1458 1615
1459 1616
1460=head1 AUTHOR 1617=head1 AUTHOR
1461 1618
1462 Marc Lehmann <schmorp@schmorp.de> 1619 Marc Lehmann <schmorp@schmorp.de>

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