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Revision 1.102 by root, Sun Apr 27 21:16:26 2008 UTC vs.
Revision 1.116 by root, Sat May 10 22:30:28 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, Coro::EV, Coro::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
7=head1 SYNOPSIS 7=head1 SYNOPSIS
8 8
9 use AnyEvent; 9 use AnyEvent;
10 10
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 ->broadcast 21 $w->recv; # enters "main loop" till $condvar gets ->send
21 $w->broadcast; # 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?
78The interface itself is vaguely similar, but not identical to the L<Event> 78The interface itself is vaguely similar, but not identical to the L<Event>
79module. 79module.
80 80
81During the first call of any watcher-creation method, the module tries 81During the first call of any watcher-creation method, the module tries
82to detect the currently loaded event loop by probing whether one of the 82to detect the currently loaded event loop by probing whether one of the
83following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, 83following modules is already loaded: L<EV>,
84L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, 84L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
85L<POE>. The first one found is used. If none are found, the module tries 85L<POE>. The first one found is used. If none are found, the module tries
86to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl 86to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
87adaptor should always succeed) in the order given. The first one that can 87adaptor should always succeed) in the order given. The first one that can
88be successfully loaded will be used. If, after this, still none could be 88be successfully loaded will be used. If, after this, still none could be
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;
283 283
284 AnyEvent::detect; # force event module to be initialised
285
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 => $pid,
290 cb => sub { 288 cb => sub {
291 my ($pid, $status) = @_; 289 my ($pid, $status) = @_;
292 warn "pid $pid exited with status $status"; 290 warn "pid $pid exited with status $status";
293 $done->broadcast; 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
300If you are familiar with some event loops you will know that all of them
301require you to run some blocking "loop", "run" or similar function that
302will actively watch for new events and call your callbacks.
303
304AnyEvent is different, it expects somebody else to run the event loop and
305will only block when necessary (usually when told by the user).
306
307The instrument to do that is called a "condition variable", so called
308because they represent a condition that must become true.
309
302Condition variables can be created by calling the C<< AnyEvent->condvar >> 310Condition variables can be created by calling the C<< AnyEvent->condvar
303method without any arguments. 311>> method, usually without arguments. The only argument pair allowed is
312C<cb>, which specifies a callback to be called when the condition variable
313becomes true.
304 314
305A condition variable waits for a condition - precisely that the C<< 315After creation, the conditon variable is "false" until it becomes "true"
306->broadcast >> method has been called. 316by calling the C<send> method.
307 317
308They are very useful to signal that a condition has been fulfilled, for 318Condition variables are similar to callbacks, except that you can
319optionally wait for them. They can also be called merge points - points
320in time where multiple outstandign events have been processed. And yet
321another way to call them is transations - each condition variable can be
322used to represent a transaction, which finishes at some point and delivers
323a result.
324
325Condition variables are very useful to signal that something has finished,
309example, if you write a module that does asynchronous http requests, 326for example, if you write a module that does asynchronous http requests,
310then a condition variable would be the ideal candidate to signal the 327then a condition variable would be the ideal candidate to signal the
311availability of results. 328availability of results. The user can either act when the callback is
329called or can synchronously C<< ->recv >> for the results.
312 330
313You can also use condition variables to block your main program until 331You can also use them to simulate traditional event loops - for example,
314an event occurs - for example, you could C<< ->wait >> in your main 332you can block your main program until an event occurs - for example, you
315program until the user clicks the Quit button in your app, which would C<< 333could C<< ->recv >> in your main program until the user clicks the Quit
316->broadcast >> the "quit" event. 334button of your app, which would C<< ->send >> the "quit" event.
317 335
318Note that condition variables recurse into the event loop - if you have 336Note that condition variables recurse into the event loop - if you have
319two pirces of code that call C<< ->wait >> in a round-robbin fashion, you 337two pieces of code that call C<< ->recv >> in a round-robbin fashion, you
320lose. Therefore, condition variables are good to export to your caller, but 338lose. Therefore, condition variables are good to export to your caller, but
321you should avoid making a blocking wait yourself, at least in callbacks, 339you should avoid making a blocking wait yourself, at least in callbacks,
322as this asks for trouble. 340as this asks for trouble.
323 341
324This object has two methods: 342Condition variables are represented by hash refs in perl, and the keys
343used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
344easy (it is often useful to build your own transaction class on top of
345AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
346it's C<new> method in your own C<new> method.
347
348There are two "sides" to a condition variable - the "producer side" which
349eventually calls C<< -> send >>, and the "consumer side", which waits
350for the send to occur.
351
352Example:
353
354 # wait till the result is ready
355 my $result_ready = AnyEvent->condvar;
356
357 # do something such as adding a timer
358 # or socket watcher the calls $result_ready->send
359 # when the "result" is ready.
360 # in this case, we simply use a timer:
361 my $w = AnyEvent->timer (
362 after => 1,
363 cb => sub { $result_ready->send },
364 );
365
366 # this "blocks" (while handling events) till the callback
367 # calls send
368 $result_ready->recv;
369
370=head3 METHODS FOR PRODUCERS
371
372These methods should only be used by the producing side, i.e. the
373code/module that eventually sends the signal. Note that it is also
374the producer side which creates the condvar in most cases, but it isn't
375uncommon for the consumer to create it as well.
325 376
326=over 4 377=over 4
327 378
379=item $cv->send (...)
380
381Flag the condition as ready - a running C<< ->recv >> and all further
382calls to C<recv> will (eventually) return after this method has been
383called. If nobody is waiting the send will be remembered.
384
385If a callback has been set on the condition variable, it is called
386immediately from within send.
387
388Any arguments passed to the C<send> call will be returned by all
389future C<< ->recv >> calls.
390
391=item $cv->croak ($error)
392
393Similar to send, but causes all call's to C<< ->recv >> to invoke
394C<Carp::croak> with the given error message/object/scalar.
395
396This can be used to signal any errors to the condition variable
397user/consumer.
398
399=item $cv->begin ([group callback])
400
328=item $cv->wait 401=item $cv->end
329 402
330Wait (blocking if necessary) until the C<< ->broadcast >> method has been 403These two methods are EXPERIMENTAL and MIGHT CHANGE.
404
405These two methods can be used to combine many transactions/events into
406one. For example, a function that pings many hosts in parallel might want
407to use a condition variable for the whole process.
408
409Every call to C<< ->begin >> will increment a counter, and every call to
410C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
411>>, the (last) callback passed to C<begin> will be executed. That callback
412is I<supposed> to call C<< ->send >>, but that is not required. If no
413callback was set, C<send> will be called without any arguments.
414
415Let's clarify this with the ping example:
416
417 my $cv = AnyEvent->condvar;
418
419 my %result;
420 $cv->begin (sub { $cv->send (\%result) });
421
422 for my $host (@list_of_hosts) {
423 $cv->begin;
424 ping_host_then_call_callback $host, sub {
425 $result{$host} = ...;
426 $cv->end;
427 };
428 }
429
430 $cv->end;
431
432This code fragment supposedly pings a number of hosts and calls
433C<send> after results for all then have have been gathered - in any
434order. To achieve this, the code issues a call to C<begin> when it starts
435each ping request and calls C<end> when it has received some result for
436it. Since C<begin> and C<end> only maintain a counter, the order in which
437results arrive is not relevant.
438
439There is an additional bracketing call to C<begin> and C<end> outside the
440loop, which serves two important purposes: first, it sets the callback
441to be called once the counter reaches C<0>, and second, it ensures that
442C<send> is called even when C<no> hosts are being pinged (the loop
443doesn't execute once).
444
445This 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>
447is called at least once, and then, for each subrequest you start, call
448C<begin> and for eahc subrequest you finish, call C<end>.
449
450=back
451
452=head3 METHODS FOR CONSUMERS
453
454These methods should only be used by the consuming side, i.e. the
455code awaits the condition.
456
457=over 4
458
459=item $cv->recv
460
461Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
331called on c<$cv>, while servicing other watchers normally. 462>> methods have been called on c<$cv>, while servicing other watchers
463normally.
332 464
333You can only wait once on a condition - additional calls will return 465You can only wait once on a condition - additional calls are valid but
334immediately. 466will return immediately.
467
468If an error condition has been set by calling C<< ->croak >>, then this
469function will call C<croak>.
470
471In list context, all parameters passed to C<send> will be returned,
472in scalar context only the first one will be returned.
335 473
336Not all event models support a blocking wait - some die in that case 474Not all event models support a blocking wait - some die in that case
337(programs might want to do that to stay interactive), so I<if you are 475(programs might want to do that to stay interactive), so I<if you are
338using this from a module, never require a blocking wait>, but let the 476using this from a module, never require a blocking wait>, but let the
339caller decide whether the call will block or not (for example, by coupling 477caller decide whether the call will block or not (for example, by coupling
340condition variables with some kind of request results and supporting 478condition variables with some kind of request results and supporting
341callbacks so the caller knows that getting the result will not block, 479callbacks so the caller knows that getting the result will not block,
342while still suppporting blocking waits if the caller so desires). 480while still suppporting blocking waits if the caller so desires).
343 481
344Another reason I<never> to C<< ->wait >> in a module is that you cannot 482Another reason I<never> to C<< ->recv >> in a module is that you cannot
345sensibly have two C<< ->wait >>'s in parallel, as that would require 483sensibly have two C<< ->recv >>'s in parallel, as that would require
346multiple interpreters or coroutines/threads, none of which C<AnyEvent> 484multiple interpreters or coroutines/threads, none of which C<AnyEvent>
347can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and 485can supply.
348L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
349from different coroutines, however).
350 486
351=item $cv->broadcast 487The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
488fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
489versions and also integrates coroutines into AnyEvent, making blocking
490C<< ->recv >> calls perfectly safe as long as they are done from another
491coroutine (one that doesn't run the event loop).
352 492
353Flag the condition as ready - a running C<< ->wait >> and all further 493You can ensure that C<< -recv >> never blocks by setting a callback and
354calls to C<wait> will (eventually) return after this method has been 494only calling C<< ->recv >> from within that callback (or at a later
355called. If nobody is waiting the broadcast will be remembered.. 495time). This will work even when the event loop does not support blocking
496waits otherwise.
497
498=item $bool = $cv->ready
499
500Returns true when the condition is "true", i.e. whether C<send> or
501C<croak> have been called.
502
503=item $cb = $cv->cb ([new callback])
504
505This is a mutator function that returns the callback set and optionally
506replaces it before doing so.
507
508The callback will be called when the condition becomes "true", i.e. when
509C<send> or C<croak> are called. Calling C<recv> inside the callback
510or at any later time is guaranteed not to block.
356 511
357=back 512=back
358
359Example:
360
361 # wait till the result is ready
362 my $result_ready = AnyEvent->condvar;
363
364 # do something such as adding a timer
365 # or socket watcher the calls $result_ready->broadcast
366 # when the "result" is ready.
367 # in this case, we simply use a timer:
368 my $w = AnyEvent->timer (
369 after => 1,
370 cb => sub { $result_ready->broadcast },
371 );
372
373 # this "blocks" (while handling events) till the watcher
374 # calls broadcast
375 $result_ready->wait;
376 513
377=head1 GLOBAL VARIABLES AND FUNCTIONS 514=head1 GLOBAL VARIABLES AND FUNCTIONS
378 515
379=over 4 516=over 4
380 517
386C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 523C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
387AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 524AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
388 525
389The known classes so far are: 526The known classes so far are:
390 527
391 AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
392 AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
393 AnyEvent::Impl::EV based on EV (an interface to libev, best choice). 528 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
394 AnyEvent::Impl::Event based on Event, second best choice. 529 AnyEvent::Impl::Event based on Event, second best choice.
530 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
395 AnyEvent::Impl::Glib based on Glib, third-best choice. 531 AnyEvent::Impl::Glib based on Glib, third-best choice.
396 AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
397 AnyEvent::Impl::Tk based on Tk, very bad choice. 532 AnyEvent::Impl::Tk based on Tk, very bad choice.
398 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). 533 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
399 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 534 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
400 AnyEvent::Impl::POE based on POE, not generic enough for full support. 535 AnyEvent::Impl::POE based on POE, not generic enough for full support.
401 536
414Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 549Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
415if necessary. You should only call this function right before you would 550if necessary. You should only call this function right before you would
416have created an AnyEvent watcher anyway, that is, as late as possible at 551have created an AnyEvent watcher anyway, that is, as late as possible at
417runtime. 552runtime.
418 553
554=item $guard = AnyEvent::post_detect { BLOCK }
555
556Arranges for the code block to be executed as soon as the event model is
557autodetected (or immediately if this has already happened).
558
559If called in scalar or list context, then it creates and returns an object
560that automatically removes the callback again when it is destroyed. See
561L<Coro::BDB> for a case where this is useful.
562
563=item @AnyEvent::post_detect
564
565If there are any code references in this array (you can C<push> to it
566before or after loading AnyEvent), then they will called directly after
567the event loop has been chosen.
568
569You should check C<$AnyEvent::MODEL> before adding to this array, though:
570if it contains a true value then the event loop has already been detected,
571and the array will be ignored.
572
573Best use C<AnyEvent::post_detect { BLOCK }> instead.
574
419=back 575=back
420 576
421=head1 WHAT TO DO IN A MODULE 577=head1 WHAT TO DO IN A MODULE
422 578
423As a module author, you should C<use AnyEvent> and call AnyEvent methods 579As a module author, you should C<use AnyEvent> and call AnyEvent methods
426Be careful when you create watchers in the module body - AnyEvent will 582Be careful when you create watchers in the module body - AnyEvent will
427decide which event module to use as soon as the first method is called, so 583decide which event module to use as soon as the first method is called, so
428by calling AnyEvent in your module body you force the user of your module 584by calling AnyEvent in your module body you force the user of your module
429to load the event module first. 585to load the event module first.
430 586
431Never call C<< ->wait >> on a condition variable unless you I<know> that 587Never call C<< ->recv >> on a condition variable unless you I<know> that
432the C<< ->broadcast >> method has been called on it already. This is 588the C<< ->send >> method has been called on it already. This is
433because it will stall the whole program, and the whole point of using 589because it will stall the whole program, and the whole point of using
434events is to stay interactive. 590events is to stay interactive.
435 591
436It is fine, however, to call C<< ->wait >> when the user of your module 592It is fine, however, to call C<< ->recv >> when the user of your module
437requests it (i.e. if you create a http request object ad have a method 593requests it (i.e. if you create a http request object ad have a method
438called C<results> that returns the results, it should call C<< ->wait >> 594called C<results> that returns the results, it should call C<< ->recv >>
439freely, as the user of your module knows what she is doing. always). 595freely, as the user of your module knows what she is doing. always).
440 596
441=head1 WHAT TO DO IN THE MAIN PROGRAM 597=head1 WHAT TO DO IN THE MAIN PROGRAM
442 598
443There will always be a single main program - the only place that should 599There will always be a single main program - the only place that should
475 631
476=item L<AnyEvent::Handle> 632=item L<AnyEvent::Handle>
477 633
478Provide read and write buffers and manages watchers for reads and writes. 634Provide read and write buffers and manages watchers for reads and writes.
479 635
480=item L<AnyEvent::Socket>
481
482Provides a means to do non-blocking connects, accepts etc.
483
484=item L<AnyEvent::HTTPD> 636=item L<AnyEvent::HTTPD>
485 637
486Provides a simple web application server framework. 638Provides a simple web application server framework.
487 639
488=item L<AnyEvent::DNS> 640=item L<AnyEvent::DNS>
511 663
512High level API for event-based execution flow control. 664High level API for event-based execution flow control.
513 665
514=item L<Coro> 666=item L<Coro>
515 667
516Has special support for AnyEvent. 668Has special support for AnyEvent via L<Coro::AnyEvent>.
669
670=item L<AnyEvent::AIO>, L<IO::AIO>
671
672Truly asynchronous I/O, should be in the toolbox of every event
673programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
674together.
675
676=item L<AnyEvent::BDB>, L<BDB>
677
678Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
679IO::AIO and AnyEvent together.
517 680
518=item L<IO::Lambda> 681=item L<IO::Lambda>
519 682
520The lambda approach to I/O - don't ask, look there. Can use AnyEvent. 683The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
521
522=item L<IO::AIO>
523
524Truly asynchronous I/O, should be in the toolbox of every event
525programmer. Can be trivially made to use AnyEvent.
526
527=item L<BDB>
528
529Truly asynchronous Berkeley DB access. Can be trivially made to use
530AnyEvent.
531 684
532=back 685=back
533 686
534=cut 687=cut
535 688
538no warnings; 691no warnings;
539use strict; 692use strict;
540 693
541use Carp; 694use Carp;
542 695
543our $VERSION = '3.3'; 696our $VERSION = '3.4';
544our $MODEL; 697our $MODEL;
545 698
546our $AUTOLOAD; 699our $AUTOLOAD;
547our @ISA; 700our @ISA;
548 701
549our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 702our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
550 703
551our @REGISTRY; 704our @REGISTRY;
552 705
553my @models = ( 706my @models = (
554 [Coro::EV:: => AnyEvent::Impl::CoroEV::],
555 [Coro::Event:: => AnyEvent::Impl::CoroEvent::],
556 [EV:: => AnyEvent::Impl::EV::], 707 [EV:: => AnyEvent::Impl::EV::],
557 [Event:: => AnyEvent::Impl::Event::], 708 [Event:: => AnyEvent::Impl::Event::],
558 [Glib:: => AnyEvent::Impl::Glib::],
559 [Tk:: => AnyEvent::Impl::Tk::], 709 [Tk:: => AnyEvent::Impl::Tk::],
560 [Wx:: => AnyEvent::Impl::POE::], 710 [Wx:: => AnyEvent::Impl::POE::],
561 [Prima:: => AnyEvent::Impl::POE::], 711 [Prima:: => AnyEvent::Impl::POE::],
562 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 712 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
563 # everything below here will not be autoprobed as the pureperl backend should work everywhere 713 # everything below here will not be autoprobed as the pureperl backend should work everywhere
714 [Glib:: => AnyEvent::Impl::Glib::],
564 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 715 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
565 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 716 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
566 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 717 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
567); 718);
568 719
569our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); 720our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
721
722our @post_detect;
723
724sub post_detect(&) {
725 my ($cb) = @_;
726
727 if ($MODEL) {
728 $cb->();
729
730 1
731 } else {
732 push @post_detect, $cb;
733
734 defined wantarray
735 ? bless \$cb, "AnyEvent::Util::Guard"
736 : ()
737 }
738}
739
740sub AnyEvent::Util::Guard::DESTROY {
741 @post_detect = grep $_ != ${$_[0]}, @post_detect;
742}
570 743
571sub detect() { 744sub detect() {
572 unless ($MODEL) { 745 unless ($MODEL) {
573 no strict 'refs'; 746 no strict 'refs';
574 747
608 last; 781 last;
609 } 782 }
610 } 783 }
611 784
612 $MODEL 785 $MODEL
613 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; 786 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
614 } 787 }
615 } 788 }
616 789
617 unshift @ISA, $MODEL; 790 unshift @ISA, $MODEL;
618 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 791 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
792
793 (shift @post_detect)->() while @post_detect;
619 } 794 }
620 795
621 $MODEL 796 $MODEL
622} 797}
623 798
633 $class->$func (@_); 808 $class->$func (@_);
634} 809}
635 810
636package AnyEvent::Base; 811package AnyEvent::Base;
637 812
638# default implementation for ->condvar, ->wait, ->broadcast 813# default implementation for ->condvar
639 814
640sub condvar { 815sub condvar {
641 bless \my $flag, "AnyEvent::Base::CondVar" 816 bless {}, AnyEvent::CondVar::
642}
643
644sub AnyEvent::Base::CondVar::broadcast {
645 ${$_[0]}++;
646}
647
648sub AnyEvent::Base::CondVar::wait {
649 AnyEvent->one_event while !${$_[0]};
650} 817}
651 818
652# default implementation for ->signal 819# default implementation for ->signal
653 820
654our %SIG_CB; 821our %SIG_CB;
727 delete $PID_CB{$pid}{$cb}; 894 delete $PID_CB{$pid}{$cb};
728 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 895 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
729 896
730 undef $CHLD_W unless keys %PID_CB; 897 undef $CHLD_W unless keys %PID_CB;
731} 898}
899
900package AnyEvent::CondVar;
901
902our @ISA = AnyEvent::CondVar::Base::;
903
904package AnyEvent::CondVar::Base;
905
906sub _send {
907 # nop
908}
909
910sub send {
911 my $cv = shift;
912 $cv->{_ae_sent} = [@_];
913 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
914 $cv->_send;
915}
916
917sub croak {
918 $_[0]{_ae_croak} = $_[1];
919 $_[0]->send;
920}
921
922sub ready {
923 $_[0]{_ae_sent}
924}
925
926sub _wait {
927 AnyEvent->one_event while !$_[0]{_ae_sent};
928}
929
930sub recv {
931 $_[0]->_wait;
932
933 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
934 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
935}
936
937sub cb {
938 $_[0]{_ae_cb} = $_[1] if @_ > 1;
939 $_[0]{_ae_cb}
940}
941
942sub begin {
943 ++$_[0]{_ae_counter};
944 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
945}
946
947sub end {
948 return if --$_[0]{_ae_counter};
949 &{ $_[0]{_ae_end_cb} } if $_[0]{_ae_end_cb};
950}
951
952# undocumented/compatibility with pre-3.4
953*broadcast = \&send;
954*wait = \&_wait;
732 955
733=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 956=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
734 957
735This is an advanced topic that you do not normally need to use AnyEvent in 958This is an advanced topic that you do not normally need to use AnyEvent in
736a module. This section is only of use to event loop authors who want to 959a module. This section is only of use to event loop authors who want to
1071file descriptor is dup()ed for each watcher. This shows that the dup() 1294file descriptor is dup()ed for each watcher. This shows that the dup()
1072employed by some adaptors is not a big performance issue (it does incur a 1295employed by some adaptors is not a big performance issue (it does incur a
1073hidden memory cost inside the kernel which is not reflected in the figures 1296hidden memory cost inside the kernel which is not reflected in the figures
1074above). 1297above).
1075 1298
1076C<POE>, regardless of underlying event loop (whether using its pure 1299C<POE>, regardless of underlying event loop (whether using its pure perl
1077perl select-based backend or the Event module, the POE-EV backend 1300select-based backend or the Event module, the POE-EV backend couldn't
1078couldn't be tested because it wasn't working) shows abysmal performance 1301be tested because it wasn't working) shows abysmal performance and
1079and memory usage: Watchers use almost 30 times as much memory as 1302memory usage with AnyEvent: Watchers use almost 30 times as much memory
1080EV watchers, and 10 times as much memory as Event (the high memory 1303as EV watchers, and 10 times as much memory as Event (the high memory
1081requirements are caused by requiring a session for each watcher). Watcher 1304requirements are caused by requiring a session for each watcher). Watcher
1082invocation speed is almost 900 times slower than with AnyEvent's pure perl 1305invocation speed is almost 900 times slower than with AnyEvent's pure perl
1306implementation.
1307
1083implementation. The design of the POE adaptor class in AnyEvent can not 1308The design of the POE adaptor class in AnyEvent can not really account
1084really account for this, as session creation overhead is small compared 1309for the performance issues, though, as session creation overhead is
1085to execution of the state machine, which is coded pretty optimally within 1310small compared to execution of the state machine, which is coded pretty
1086L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow. 1311optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that
1312using multiple sessions is not a good approach, especially regarding
1313memory usage, even the author of POE could not come up with a faster
1314design).
1087 1315
1088=head3 Summary 1316=head3 Summary
1089 1317
1090=over 4 1318=over 4
1091 1319
1170 1398
1171=head3 Summary 1399=head3 Summary
1172 1400
1173=over 4 1401=over 4
1174 1402
1175=item * The pure perl implementation performs extremely well, considering 1403=item * The pure perl implementation performs extremely well.
1176that it uses select.
1177 1404
1178=item * Avoid Glib or POE in large projects where performance matters. 1405=item * Avoid Glib or POE in large projects where performance matters.
1179 1406
1180=back 1407=back
1181 1408
1230 1457
1231 1458
1232=head1 FORK 1459=head1 FORK
1233 1460
1234Most event libraries are not fork-safe. The ones who are usually are 1461Most event libraries are not fork-safe. The ones who are usually are
1235because they are so inefficient. Only L<EV> is fully fork-aware. 1462because they rely on inefficient but fork-safe C<select> or C<poll>
1463calls. Only L<EV> is fully fork-aware.
1236 1464
1237If you have to fork, you must either do so I<before> creating your first 1465If you have to fork, you must either do so I<before> creating your first
1238watcher OR you must not use AnyEvent at all in the child. 1466watcher OR you must not use AnyEvent at all in the child.
1239 1467
1240 1468
1252 1480
1253 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } 1481 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1254 1482
1255 use AnyEvent; 1483 use AnyEvent;
1256 1484
1485Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1486be used to probe what backend is used and gain other information (which is
1487probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1488
1257 1489
1258=head1 SEE ALSO 1490=head1 SEE ALSO
1259 1491
1260Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, 1492Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1261L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,
1262L<Event::Lib>, L<Qt>, L<POE>. 1493L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1263 1494
1264Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, 1495Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1265L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, 1496L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1266L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, 1497L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1267L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. 1498L<AnyEvent::Impl::POE>.
1499
1500Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1268 1501
1269Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. 1502Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.
1270 1503
1271 1504
1272=head1 AUTHOR 1505=head1 AUTHOR

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