ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/AnyEvent/lib/AnyEvent.pm
(Generate patch)

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.115 by root, Sat May 10 21:47:28 2008 UTC vs.
Revision 1.155 by root, Fri Jun 6 07:07:01 2008 UTC

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->send; # wake up current and all future recv's
21 $w->recv; # enters "main loop" till $condvar gets ->send 21 $w->recv; # enters "main loop" till $condvar gets ->send
22
23=head1 INTRODUCTION/TUTORIAL
24
25This manpage is mainly a reference manual. If you are interested
26in a tutorial or some gentle introduction, have a look at the
27L<AnyEvent::Intro> manpage.
22 28
23=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 29=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24 30
25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 31Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26nowadays. So what is different about AnyEvent? 32nowadays. So what is different about AnyEvent?
48isn't itself. What's worse, all the potential users of your module are 54isn't itself. What's worse, all the potential users of your module are
49I<also> forced to use the same event loop you use. 55I<also> forced to use the same event loop you use.
50 56
51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 57AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52fine. AnyEvent + Tk works fine etc. etc. but none of these work together 58fine. 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 59with 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, 60your 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 61too. But if your module uses AnyEvent, it works transparently with all
56event models it supports (including stuff like POE and IO::Async, as long 62event 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 63as those use one of the supported event loops. It is trivial to add new
58event loops to AnyEvent, too, so it is future-proof). 64event loops to AnyEvent, too, so it is future-proof).
59 65
60In addition to being free of having to use I<the one and only true event 66In 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 67model>, 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 68modules, 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 69follow. 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 70offering the functionality that is necessary, in as thin as a wrapper as
65technically possible. 71technically possible.
66 72
73Of course, AnyEvent comes with a big (and fully optional!) toolbox
74of useful functionality, such as an asynchronous DNS resolver, 100%
75non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
76such as Windows) and lots of real-world knowledge and workarounds for
77platform bugs and differences.
78
67Of course, if you want lots of policy (this can arguably be somewhat 79Now, 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 80useful) and you want to force your users to use the one and only event
69model, you should I<not> use this module. 81model, you should I<not> use this module.
70 82
71=head1 DESCRIPTION 83=head1 DESCRIPTION
72 84
102starts using it, all bets are off. Maybe you should tell their authors to 114starts using it, all bets are off. Maybe you should tell their authors to
103use AnyEvent so their modules work together with others seamlessly... 115use AnyEvent so their modules work together with others seamlessly...
104 116
105The pure-perl implementation of AnyEvent is called 117The pure-perl implementation of AnyEvent is called
106C<AnyEvent::Impl::Perl>. Like other event modules you can load it 118C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107explicitly. 119explicitly and enjoy the high availability of that event loop :)
108 120
109=head1 WATCHERS 121=head1 WATCHERS
110 122
111AnyEvent has the central concept of a I<watcher>, which is an object that 123AnyEvent 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 124stores relevant data for each kind of event you are waiting for, such as
113the callback to call, the filehandle to watch, etc. 125the callback to call, the file handle to watch, etc.
114 126
115These watchers are normal Perl objects with normal Perl lifetime. After 127These watchers are normal Perl objects with normal Perl lifetime. After
116creating a watcher it will immediately "watch" for events and invoke the 128creating a watcher it will immediately "watch" for events and invoke the
117callback when the event occurs (of course, only when the event model 129callback when the event occurs (of course, only when the event model
118is in control). 130is in control).
126Many watchers either are used with "recursion" (repeating timers for 138Many watchers either are used with "recursion" (repeating timers for
127example), or need to refer to their watcher object in other ways. 139example), or need to refer to their watcher object in other ways.
128 140
129An any way to achieve that is this pattern: 141An any way to achieve that is this pattern:
130 142
131 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 143 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132 # you can use $w here, for example to undef it 144 # you can use $w here, for example to undef it
133 undef $w; 145 undef $w;
134 }); 146 });
135 147
136Note that C<my $w; $w => combination. This is necessary because in Perl, 148Note that C<my $w; $w => combination. This is necessary because in Perl,
137my variables are only visible after the statement in which they are 149my variables are only visible after the statement in which they are
138declared. 150declared.
139 151
227timers. 239timers.
228 240
229AnyEvent always prefers relative timers, if available, matching the 241AnyEvent always prefers relative timers, if available, matching the
230AnyEvent API. 242AnyEvent API.
231 243
244AnyEvent has two additional methods that return the "current time":
245
246=over 4
247
248=item AnyEvent->time
249
250This returns the "current wallclock time" as a fractional number of
251seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
252return, and the result is guaranteed to be compatible with those).
253
254It progresses independently of any event loop processing, i.e. each call
255will check the system clock, which usually gets updated frequently.
256
257=item AnyEvent->now
258
259This also returns the "current wallclock time", but unlike C<time>, above,
260this value might change only once per event loop iteration, depending on
261the event loop (most return the same time as C<time>, above). This is the
262time that AnyEvent's timers get scheduled against.
263
264I<In almost all cases (in all cases if you don't care), this is the
265function to call when you want to know the current time.>
266
267This function is also often faster then C<< AnyEvent->time >>, and
268thus the preferred method if you want some timestamp (for example,
269L<AnyEvent::Handle> uses this to update it's activity timeouts).
270
271The rest of this section is only of relevance if you try to be very exact
272with your timing, you can skip it without bad conscience.
273
274For a practical example of when these times differ, consider L<Event::Lib>
275and L<EV> and the following set-up:
276
277The event loop is running and has just invoked one of your callback at
278time=500 (assume no other callbacks delay processing). In your callback,
279you wait a second by executing C<sleep 1> (blocking the process for a
280second) and then (at time=501) you create a relative timer that fires
281after three seconds.
282
283With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
284both return C<501>, because that is the current time, and the timer will
285be scheduled to fire at time=504 (C<501> + C<3>).
286
287With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
288time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
289last event processing phase started. With L<EV>, your timer gets scheduled
290to run at time=503 (C<500> + C<3>).
291
292In one sense, L<Event::Lib> is more exact, as it uses the current time
293regardless of any delays introduced by event processing. However, most
294callbacks do not expect large delays in processing, so this causes a
295higher drift (and a lot more system calls to get the current time).
296
297In another sense, L<EV> is more exact, as your timer will be scheduled at
298the same time, regardless of how long event processing actually took.
299
300In either case, if you care (and in most cases, you don't), then you
301can get whatever behaviour you want with any event loop, by taking the
302difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
303account.
304
305=back
306
232=head2 SIGNAL WATCHERS 307=head2 SIGNAL WATCHERS
233 308
234You can watch for signals using a signal watcher, C<signal> is the signal 309You can watch for signals using a signal watcher, C<signal> is the signal
235I<name> without any C<SIG> prefix, C<cb> is the Perl callback to 310I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
236be invoked whenever a signal occurs. 311be invoked whenever a signal occurs.
237 312
238Although the callback might get passed parameters, their value and 313Although the callback might get passed parameters, their value and
239presence is undefined and you cannot rely on them. Portable AnyEvent 314presence is undefined and you cannot rely on them. Portable AnyEvent
240callbacks cannot use arguments passed to signal watcher callbacks. 315callbacks cannot use arguments passed to signal watcher callbacks.
241 316
242Multiple signal occurances can be clumped together into one callback 317Multiple signal occurrences can be clumped together into one callback
243invocation, and callback invocation will be synchronous. synchronous means 318invocation, and callback invocation will be synchronous. Synchronous means
244that it might take a while until the signal gets handled by the process, 319that it might take a while until the signal gets handled by the process,
245but it is guarenteed not to interrupt any other callbacks. 320but it is guaranteed not to interrupt any other callbacks.
246 321
247The main advantage of using these watchers is that you can share a signal 322The main advantage of using these watchers is that you can share a signal
248between multiple watchers. 323between multiple watchers.
249 324
250This watcher might use C<%SIG>, so programs overwriting those signals 325This watcher might use C<%SIG>, so programs overwriting those signals
277AnyEvent program, you I<have> to create at least one watcher before you 352AnyEvent program, you I<have> to create at least one watcher before you
278C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 353C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279 354
280Example: fork a process and wait for it 355Example: fork a process and wait for it
281 356
282 my $done = AnyEvent->condvar; 357 my $done = AnyEvent->condvar;
283 358
284 my $pid = fork or exit 5; 359 my $pid = fork or exit 5;
285 360
286 my $w = AnyEvent->child ( 361 my $w = AnyEvent->child (
287 pid => $pid, 362 pid => $pid,
288 cb => sub { 363 cb => sub {
289 my ($pid, $status) = @_; 364 my ($pid, $status) = @_;
290 warn "pid $pid exited with status $status"; 365 warn "pid $pid exited with status $status";
291 $done->send; 366 $done->send;
292 }, 367 },
293 ); 368 );
294 369
295 # do something else, then wait for process exit 370 # do something else, then wait for process exit
296 $done->recv; 371 $done->recv;
297 372
298=head2 CONDITION VARIABLES 373=head2 CONDITION VARIABLES
299 374
300If you are familiar with some event loops you will know that all of them 375If 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 376require you to run some blocking "loop", "run" or similar function that
310Condition variables can be created by calling the C<< AnyEvent->condvar 385Condition variables can be created by calling the C<< AnyEvent->condvar
311>> method, usually without arguments. The only argument pair allowed is 386>> method, usually without arguments. The only argument pair allowed is
312C<cb>, which specifies a callback to be called when the condition variable 387C<cb>, which specifies a callback to be called when the condition variable
313becomes true. 388becomes true.
314 389
315After creation, the conditon variable is "false" until it becomes "true" 390After creation, the condition variable is "false" until it becomes "true"
316by calling the C<send> method. 391by calling the C<send> method (or calling the condition variable as if it
392were a callback, read about the caveats in the description for the C<<
393->send >> method).
317 394
318Condition variables are similar to callbacks, except that you can 395Condition variables are similar to callbacks, except that you can
319optionally wait for them. They can also be called merge points - points 396optionally wait for them. They can also be called merge points - points
320in time where multiple outstandign events have been processed. And yet 397in time where multiple outstanding events have been processed. And yet
321another way to call them is transations - each condition variable can be 398another way to call them is transactions - each condition variable can be
322used to represent a transaction, which finishes at some point and delivers 399used to represent a transaction, which finishes at some point and delivers
323a result. 400a result.
324 401
325Condition variables are very useful to signal that something has finished, 402Condition variables are very useful to signal that something has finished,
326for example, if you write a module that does asynchronous http requests, 403for example, if you write a module that does asynchronous http requests,
332you can block your main program until an event occurs - for example, you 409you can block your main program until an event occurs - for example, you
333could C<< ->recv >> in your main program until the user clicks the Quit 410could C<< ->recv >> in your main program until the user clicks the Quit
334button of your app, which would C<< ->send >> the "quit" event. 411button of your app, which would C<< ->send >> the "quit" event.
335 412
336Note that condition variables recurse into the event loop - if you have 413Note that condition variables recurse into the event loop - if you have
337two pieces of code that call C<< ->recv >> in a round-robbin fashion, you 414two pieces of code that call C<< ->recv >> in a round-robin fashion, you
338lose. Therefore, condition variables are good to export to your caller, but 415lose. Therefore, condition variables are good to export to your caller, but
339you should avoid making a blocking wait yourself, at least in callbacks, 416you should avoid making a blocking wait yourself, at least in callbacks,
340as this asks for trouble. 417as this asks for trouble.
341 418
342Condition variables are represented by hash refs in perl, and the keys 419Condition variables are represented by hash refs in perl, and the keys
347 424
348There are two "sides" to a condition variable - the "producer side" which 425There are two "sides" to a condition variable - the "producer side" which
349eventually calls C<< -> send >>, and the "consumer side", which waits 426eventually calls C<< -> send >>, and the "consumer side", which waits
350for the send to occur. 427for the send to occur.
351 428
352Example: 429Example: wait for a timer.
353 430
354 # wait till the result is ready 431 # wait till the result is ready
355 my $result_ready = AnyEvent->condvar; 432 my $result_ready = AnyEvent->condvar;
356 433
357 # do something such as adding a timer 434 # do something such as adding a timer
365 442
366 # this "blocks" (while handling events) till the callback 443 # this "blocks" (while handling events) till the callback
367 # calls send 444 # calls send
368 $result_ready->recv; 445 $result_ready->recv;
369 446
447Example: wait for a timer, but take advantage of the fact that
448condition variables are also code references.
449
450 my $done = AnyEvent->condvar;
451 my $delay = AnyEvent->timer (after => 5, cb => $done);
452 $done->recv;
453
370=head3 METHODS FOR PRODUCERS 454=head3 METHODS FOR PRODUCERS
371 455
372These methods should only be used by the producing side, i.e. the 456These methods should only be used by the producing side, i.e. the
373code/module that eventually sends the signal. Note that it is also 457code/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 458the producer side which creates the condvar in most cases, but it isn't
385If a callback has been set on the condition variable, it is called 469If a callback has been set on the condition variable, it is called
386immediately from within send. 470immediately from within send.
387 471
388Any arguments passed to the C<send> call will be returned by all 472Any arguments passed to the C<send> call will be returned by all
389future C<< ->recv >> calls. 473future C<< ->recv >> calls.
474
475Condition variables are overloaded so one can call them directly
476(as a code reference). Calling them directly is the same as calling
477C<send>. Note, however, that many C-based event loops do not handle
478overloading, so as tempting as it may be, passing a condition variable
479instead of a callback does not work. Both the pure perl and EV loops
480support overloading, however, as well as all functions that use perl to
481invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
482example).
390 483
391=item $cv->croak ($error) 484=item $cv->croak ($error)
392 485
393Similar to send, but causes all call's to C<< ->recv >> to invoke 486Similar to send, but causes all call's to C<< ->recv >> to invoke
394C<Carp::croak> with the given error message/object/scalar. 487C<Carp::croak> with the given error message/object/scalar.
443doesn't execute once). 536doesn't execute once).
444 537
445This is the general pattern when you "fan out" into multiple subrequests: 538This 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> 539use 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 540is called at least once, and then, for each subrequest you start, call
448C<begin> and for eahc subrequest you finish, call C<end>. 541C<begin> and for each subrequest you finish, call C<end>.
449 542
450=back 543=back
451 544
452=head3 METHODS FOR CONSUMERS 545=head3 METHODS FOR CONSUMERS
453 546
475(programs might want to do that to stay interactive), so I<if you are 568(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 569using 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 570caller decide whether the call will block or not (for example, by coupling
478condition variables with some kind of request results and supporting 571condition variables with some kind of request results and supporting
479callbacks so the caller knows that getting the result will not block, 572callbacks so the caller knows that getting the result will not block,
480while still suppporting blocking waits if the caller so desires). 573while still supporting blocking waits if the caller so desires).
481 574
482Another reason I<never> to C<< ->recv >> in a module is that you cannot 575Another reason I<never> to C<< ->recv >> in a module is that you cannot
483sensibly have two C<< ->recv >>'s in parallel, as that would require 576sensibly have two C<< ->recv >>'s in parallel, as that would require
484multiple interpreters or coroutines/threads, none of which C<AnyEvent> 577multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485can supply. 578can supply.
504 597
505This is a mutator function that returns the callback set and optionally 598This is a mutator function that returns the callback set and optionally
506replaces it before doing so. 599replaces it before doing so.
507 600
508The callback will be called when the condition becomes "true", i.e. when 601The 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 602C<send> or C<croak> are called, with the only argument being the condition
510or at any later time is guaranteed not to block. 603variable itself. Calling C<recv> inside the callback or at any later time
604is guaranteed not to block.
511 605
512=back 606=back
513 607
514=head1 GLOBAL VARIABLES AND FUNCTIONS 608=head1 GLOBAL VARIABLES AND FUNCTIONS
515 609
601 695
602If it doesn't care, it can just "use AnyEvent" and use it itself, or not 696If 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 697do anything special (it does not need to be event-based) and let AnyEvent
604decide which implementation to chose if some module relies on it. 698decide which implementation to chose if some module relies on it.
605 699
606If the main program relies on a specific event model. For example, in 700If 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 701Gtk2 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 702event module before loading AnyEvent or any module that uses it: generally
609speaking, you should load it as early as possible. The reason is that 703speaking, you should load it as early as possible. The reason is that
610modules might create watchers when they are loaded, and AnyEvent will 704modules 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 705decide 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. 706might chose the wrong one unless you load the correct one yourself.
613 707
614You can chose to use a rather inefficient pure-perl implementation by 708You can chose to use a pure-perl implementation by loading the
615loading the C<AnyEvent::Impl::Perl> module, which gives you similar 709C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
616behaviour everywhere, but letting AnyEvent chose is generally better. 710everywhere, but letting AnyEvent chose the model is generally better.
711
712=head2 MAINLOOP EMULATION
713
714Sometimes (often for short test scripts, or even standalone programs who
715only want to use AnyEvent), you do not want to run a specific event loop.
716
717In that case, you can use a condition variable like this:
718
719 AnyEvent->condvar->recv;
720
721This has the effect of entering the event loop and looping forever.
722
723Note that usually your program has some exit condition, in which case
724it is better to use the "traditional" approach of storing a condition
725variable somewhere, waiting for it, and sending it when the program should
726exit cleanly.
727
617 728
618=head1 OTHER MODULES 729=head1 OTHER MODULES
619 730
620The following is a non-exhaustive list of additional modules that use 731The following is a non-exhaustive list of additional modules that use
621AnyEvent and can therefore be mixed easily with other AnyEvent modules 732AnyEvent and can therefore be mixed easily with other AnyEvent modules
631 742
632=item L<AnyEvent::Handle> 743=item L<AnyEvent::Handle>
633 744
634Provide read and write buffers and manages watchers for reads and writes. 745Provide read and write buffers and manages watchers for reads and writes.
635 746
747=item L<AnyEvent::Socket>
748
749Provides various utility functions for (internet protocol) sockets,
750addresses and name resolution. Also functions to create non-blocking tcp
751connections or tcp servers, with IPv6 and SRV record support and more.
752
753=item L<AnyEvent::DNS>
754
755Provides rich asynchronous DNS resolver capabilities.
756
757=item L<AnyEvent::HTTP>
758
759A simple-to-use HTTP library that is capable of making a lot of concurrent
760HTTP requests.
761
636=item L<AnyEvent::HTTPD> 762=item L<AnyEvent::HTTPD>
637 763
638Provides a simple web application server framework. 764Provides a simple web application server framework.
639
640=item L<AnyEvent::DNS>
641
642Provides asynchronous DNS resolver capabilities, beyond what
643L<AnyEvent::Util> offers.
644 765
645=item L<AnyEvent::FastPing> 766=item L<AnyEvent::FastPing>
646 767
647The fastest ping in the west. 768The fastest ping in the west.
648 769
691no warnings; 812no warnings;
692use strict; 813use strict;
693 814
694use Carp; 815use Carp;
695 816
696our $VERSION = '3.4'; 817our $VERSION = 4.14;
697our $MODEL; 818our $MODEL;
698 819
699our $AUTOLOAD; 820our $AUTOLOAD;
700our @ISA; 821our @ISA;
701 822
823our @REGISTRY;
824
825our $WIN32;
826
827BEGIN {
828 my $win32 = ! ! ($^O =~ /mswin32/i);
829 eval "sub WIN32(){ $win32 }";
830}
831
702our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 832our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
703 833
704our @REGISTRY; 834our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
835
836{
837 my $idx;
838 $PROTOCOL{$_} = ++$idx
839 for reverse split /\s*,\s*/,
840 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
841}
705 842
706my @models = ( 843my @models = (
707 [EV:: => AnyEvent::Impl::EV::], 844 [EV:: => AnyEvent::Impl::EV::],
708 [Event:: => AnyEvent::Impl::Event::], 845 [Event:: => AnyEvent::Impl::Event::],
709 [Tk:: => AnyEvent::Impl::Tk::],
710 [Wx:: => AnyEvent::Impl::POE::],
711 [Prima:: => AnyEvent::Impl::POE::],
712 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 846 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
713 # everything below here will not be autoprobed as the pureperl backend should work everywhere 847 # everything below here will not be autoprobed
714 [Glib:: => AnyEvent::Impl::Glib::], 848 # as the pureperl backend should work everywhere
849 # and is usually faster
850 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
851 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
715 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 852 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
716 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 853 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
717 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 854 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
855 [Wx:: => AnyEvent::Impl::POE::],
856 [Prima:: => AnyEvent::Impl::POE::],
718); 857);
719 858
720our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); 859our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
721 860
722our @post_detect; 861our @post_detect;
723 862
724sub post_detect(&) { 863sub post_detect(&) {
725 my ($cb) = @_; 864 my ($cb) = @_;
730 1 869 1
731 } else { 870 } else {
732 push @post_detect, $cb; 871 push @post_detect, $cb;
733 872
734 defined wantarray 873 defined wantarray
735 ? bless \$cb, "AnyEvent::Util::Guard" 874 ? bless \$cb, "AnyEvent::Util::PostDetect"
736 : () 875 : ()
737 } 876 }
738} 877}
739 878
740sub AnyEvent::Util::Guard::DESTROY { 879sub AnyEvent::Util::PostDetect::DESTROY {
741 @post_detect = grep $_ != ${$_[0]}, @post_detect; 880 @post_detect = grep $_ != ${$_[0]}, @post_detect;
742} 881}
743 882
744sub detect() { 883sub detect() {
745 unless ($MODEL) { 884 unless ($MODEL) {
746 no strict 'refs'; 885 no strict 'refs';
886 local $SIG{__DIE__};
747 887
748 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 888 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
749 my $model = "AnyEvent::Impl::$1"; 889 my $model = "AnyEvent::Impl::$1";
750 if (eval "require $model") { 890 if (eval "require $model") {
751 $MODEL = $model; 891 $MODEL = $model;
808 $class->$func (@_); 948 $class->$func (@_);
809} 949}
810 950
811package AnyEvent::Base; 951package AnyEvent::Base;
812 952
953# default implementation for now and time
954
955use Time::HiRes ();
956
957sub time { Time::HiRes::time }
958sub now { Time::HiRes::time }
959
813# default implementation for ->condvar 960# default implementation for ->condvar
814 961
815sub condvar { 962sub condvar {
816 bless {}, "AnyEvent::Base::CondVar" 963 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
817} 964}
818 965
819# default implementation for ->signal 966# default implementation for ->signal
820 967
821our %SIG_CB; 968our %SIG_CB;
874 or Carp::croak "required option 'pid' is missing"; 1021 or Carp::croak "required option 'pid' is missing";
875 1022
876 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1023 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
877 1024
878 unless ($WNOHANG) { 1025 unless ($WNOHANG) {
879 $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; 1026 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
880 } 1027 }
881 1028
882 unless ($CHLD_W) { 1029 unless ($CHLD_W) {
883 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1030 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
884 # child could be a zombie already, so make at least one round 1031 # child could be a zombie already, so make at least one round
895 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1042 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
896 1043
897 undef $CHLD_W unless keys %PID_CB; 1044 undef $CHLD_W unless keys %PID_CB;
898} 1045}
899 1046
900package AnyEvent::Base::CondVar; 1047package AnyEvent::CondVar;
901 1048
902# wake up the waiter 1049our @ISA = AnyEvent::CondVar::Base::;
1050
1051package AnyEvent::CondVar::Base;
1052
1053use overload
1054 '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1055 fallback => 1;
1056
903sub _send { 1057sub _send {
904 &{ delete $_[0]{_ae_cb} } if $_[0]{_ae_cb}; 1058 # nop
905} 1059}
906 1060
907sub send { 1061sub send {
908 my $cv = shift; 1062 my $cv = shift;
909 $cv->{_ae_sent} = [@_]; 1063 $cv->{_ae_sent} = [@_];
1064 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
910 $cv->_send; 1065 $cv->_send;
911} 1066}
912 1067
913sub croak { 1068sub croak {
914 $_[0]{_ae_croak} = $_[1]; 1069 $_[0]{_ae_croak} = $_[1];
917 1072
918sub ready { 1073sub ready {
919 $_[0]{_ae_sent} 1074 $_[0]{_ae_sent}
920} 1075}
921 1076
1077sub _wait {
1078 AnyEvent->one_event while !$_[0]{_ae_sent};
1079}
1080
922sub recv { 1081sub recv {
923 AnyEvent->one_event while !$_[0]{_ae_sent}; 1082 $_[0]->_wait;
924 1083
925 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1084 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
926 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1085 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
927} 1086}
928 1087
936 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 1095 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
937} 1096}
938 1097
939sub end { 1098sub end {
940 return if --$_[0]{_ae_counter}; 1099 return if --$_[0]{_ae_counter};
941 &{ $_[0]{_ae_end_cb} } if $_[0]{_ae_end_cb}; 1100 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
942} 1101}
943 1102
944# undocumented/compatibility with pre-3.4 1103# undocumented/compatibility with pre-3.4
945*broadcast = \&send; 1104*broadcast = \&send;
946*wait = \&recv; 1105*wait = \&_wait;
947 1106
948=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1107=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
949 1108
950This is an advanced topic that you do not normally need to use AnyEvent in 1109This is an advanced topic that you do not normally need to use AnyEvent in
951a module. This section is only of use to event loop authors who want to 1110a module. This section is only of use to event loop authors who want to
1008model it chooses. 1167model it chooses.
1009 1168
1010=item C<PERL_ANYEVENT_MODEL> 1169=item C<PERL_ANYEVENT_MODEL>
1011 1170
1012This can be used to specify the event model to be used by AnyEvent, before 1171This can be used to specify the event model to be used by AnyEvent, before
1013autodetection and -probing kicks in. It must be a string consisting 1172auto detection and -probing kicks in. It must be a string consisting
1014entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 1173entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1015and the resulting module name is loaded and if the load was successful, 1174and the resulting module name is loaded and if the load was successful,
1016used as event model. If it fails to load AnyEvent will proceed with 1175used as event model. If it fails to load AnyEvent will proceed with
1017autodetection and -probing. 1176auto detection and -probing.
1018 1177
1019This functionality might change in future versions. 1178This functionality might change in future versions.
1020 1179
1021For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 1180For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1022could start your program like this: 1181could start your program like this:
1023 1182
1024 PERL_ANYEVENT_MODEL=Perl perl ... 1183 PERL_ANYEVENT_MODEL=Perl perl ...
1184
1185=item C<PERL_ANYEVENT_PROTOCOLS>
1186
1187Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1188for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1189of auto probing).
1190
1191Must be set to a comma-separated list of protocols or address families,
1192current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1193used, and preference will be given to protocols mentioned earlier in the
1194list.
1195
1196This variable can effectively be used for denial-of-service attacks
1197against local programs (e.g. when setuid), although the impact is likely
1198small, as the program has to handle connection errors already-
1199
1200Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1201but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1202- only support IPv4, never try to resolve or contact IPv6
1203addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1204IPv6, but prefer IPv6 over IPv4.
1205
1206=item C<PERL_ANYEVENT_EDNS0>
1207
1208Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1209for DNS. This extension is generally useful to reduce DNS traffic, but
1210some (broken) firewalls drop such DNS packets, which is why it is off by
1211default.
1212
1213Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1214EDNS0 in its DNS requests.
1215
1216=item C<PERL_ANYEVENT_MAX_FORKS>
1217
1218The maximum number of child processes that C<AnyEvent::Util::fork_call>
1219will create in parallel.
1025 1220
1026=back 1221=back
1027 1222
1028=head1 EXAMPLE PROGRAM 1223=head1 EXAMPLE PROGRAM
1029 1224
1040 poll => 'r', 1235 poll => 'r',
1041 cb => sub { 1236 cb => sub {
1042 warn "io event <$_[0]>\n"; # will always output <r> 1237 warn "io event <$_[0]>\n"; # will always output <r>
1043 chomp (my $input = <STDIN>); # read a line 1238 chomp (my $input = <STDIN>); # read a line
1044 warn "read: $input\n"; # output what has been read 1239 warn "read: $input\n"; # output what has been read
1045 $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i 1240 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1046 }, 1241 },
1047 ); 1242 );
1048 1243
1049 my $time_watcher; # can only be used once 1244 my $time_watcher; # can only be used once
1050 1245
1055 }); 1250 });
1056 } 1251 }
1057 1252
1058 new_timer; # create first timer 1253 new_timer; # create first timer
1059 1254
1060 $cv->wait; # wait until user enters /^q/i 1255 $cv->recv; # wait until user enters /^q/i
1061 1256
1062=head1 REAL-WORLD EXAMPLE 1257=head1 REAL-WORLD EXAMPLE
1063 1258
1064Consider the L<Net::FCP> module. It features (among others) the following 1259Consider the L<Net::FCP> module. It features (among others) the following
1065API calls, which are to freenet what HTTP GET requests are to http: 1260API calls, which are to freenet what HTTP GET requests are to http:
1115 syswrite $txn->{fh}, $txn->{request} 1310 syswrite $txn->{fh}, $txn->{request}
1116 or die "connection or write error"; 1311 or die "connection or write error";
1117 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); 1312 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1118 1313
1119Again, C<fh_ready_r> waits till all data has arrived, and then stores the 1314Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1120result and signals any possible waiters that the request ahs finished: 1315result and signals any possible waiters that the request has finished:
1121 1316
1122 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; 1317 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1123 1318
1124 if (end-of-file or data complete) { 1319 if (end-of-file or data complete) {
1125 $txn->{result} = $txn->{buf}; 1320 $txn->{result} = $txn->{buf};
1126 $txn->{finished}->broadcast; 1321 $txn->{finished}->send;
1127 $txb->{cb}->($txn) of $txn->{cb}; # also call callback 1322 $txb->{cb}->($txn) of $txn->{cb}; # also call callback
1128 } 1323 }
1129 1324
1130The C<result> method, finally, just waits for the finished signal (if the 1325The C<result> method, finally, just waits for the finished signal (if the
1131request was already finished, it doesn't wait, of course, and returns the 1326request was already finished, it doesn't wait, of course, and returns the
1132data: 1327data:
1133 1328
1134 $txn->{finished}->wait; 1329 $txn->{finished}->recv;
1135 return $txn->{result}; 1330 return $txn->{result};
1136 1331
1137The actual code goes further and collects all errors (C<die>s, exceptions) 1332The actual code goes further and collects all errors (C<die>s, exceptions)
1138that occured during request processing. The C<result> method detects 1333that occurred during request processing. The C<result> method detects
1139whether an exception as thrown (it is stored inside the $txn object) 1334whether an exception as thrown (it is stored inside the $txn object)
1140and just throws the exception, which means connection errors and other 1335and just throws the exception, which means connection errors and other
1141problems get reported tot he code that tries to use the result, not in a 1336problems get reported tot he code that tries to use the result, not in a
1142random callback. 1337random callback.
1143 1338
1174 1369
1175 my $quit = AnyEvent->condvar; 1370 my $quit = AnyEvent->condvar;
1176 1371
1177 $fcp->txn_client_get ($url)->cb (sub { 1372 $fcp->txn_client_get ($url)->cb (sub {
1178 ... 1373 ...
1179 $quit->broadcast; 1374 $quit->send;
1180 }); 1375 });
1181 1376
1182 $quit->wait; 1377 $quit->recv;
1183 1378
1184 1379
1185=head1 BENCHMARKS 1380=head1 BENCHMARKS
1186 1381
1187To give you an idea of the performance and overheads that AnyEvent adds 1382To give you an idea of the performance and overheads that AnyEvent adds
1189of various event loops I prepared some benchmarks. 1384of various event loops I prepared some benchmarks.
1190 1385
1191=head2 BENCHMARKING ANYEVENT OVERHEAD 1386=head2 BENCHMARKING ANYEVENT OVERHEAD
1192 1387
1193Here is a benchmark of various supported event models used natively and 1388Here is a benchmark of various supported event models used natively and
1194through anyevent. The benchmark creates a lot of timers (with a zero 1389through AnyEvent. The benchmark creates a lot of timers (with a zero
1195timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 1390timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1196which it is), lets them fire exactly once and destroys them again. 1391which it is), lets them fire exactly once and destroys them again.
1197 1392
1198Source code for this benchmark is found as F<eg/bench> in the AnyEvent 1393Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1199distribution. 1394distribution.
1216all watchers, to avoid adding memory overhead. That means closure creation 1411all watchers, to avoid adding memory overhead. That means closure creation
1217and memory usage is not included in the figures. 1412and memory usage is not included in the figures.
1218 1413
1219I<invoke> is the time, in microseconds, used to invoke a simple 1414I<invoke> is the time, in microseconds, used to invoke a simple
1220callback. The callback simply counts down a Perl variable and after it was 1415callback. The callback simply counts down a Perl variable and after it was
1221invoked "watcher" times, it would C<< ->broadcast >> a condvar once to 1416invoked "watcher" times, it would C<< ->send >> a condvar once to
1222signal the end of this phase. 1417signal the end of this phase.
1223 1418
1224I<destroy> is the time, in microseconds, that it takes to destroy a single 1419I<destroy> is the time, in microseconds, that it takes to destroy a single
1225watcher. 1420watcher.
1226 1421
1322 1517
1323=back 1518=back
1324 1519
1325=head2 BENCHMARKING THE LARGE SERVER CASE 1520=head2 BENCHMARKING THE LARGE SERVER CASE
1326 1521
1327This benchmark atcually benchmarks the event loop itself. It works by 1522This benchmark actually benchmarks the event loop itself. It works by
1328creating a number of "servers": each server consists of a socketpair, a 1523creating a number of "servers": each server consists of a socket pair, a
1329timeout watcher that gets reset on activity (but never fires), and an I/O 1524timeout watcher that gets reset on activity (but never fires), and an I/O
1330watcher waiting for input on one side of the socket. Each time the socket 1525watcher waiting for input on one side of the socket. Each time the socket
1331watcher reads a byte it will write that byte to a random other "server". 1526watcher reads a byte it will write that byte to a random other "server".
1332 1527
1333The effect is that there will be a lot of I/O watchers, only part of which 1528The effect is that there will be a lot of I/O watchers, only part of which
1334are active at any one point (so there is a constant number of active 1529are active at any one point (so there is a constant number of active
1335fds for each loop iterstaion, but which fds these are is random). The 1530fds for each loop iteration, but which fds these are is random). The
1336timeout is reset each time something is read because that reflects how 1531timeout is reset each time something is read because that reflects how
1337most timeouts work (and puts extra pressure on the event loops). 1532most timeouts work (and puts extra pressure on the event loops).
1338 1533
1339In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 1534In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1340(1%) are active. This mirrors the activity of large servers with many 1535(1%) are active. This mirrors the activity of large servers with many
1341connections, most of which are idle at any one point in time. 1536connections, most of which are idle at any one point in time.
1342 1537
1343Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 1538Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1344distribution. 1539distribution.
1346=head3 Explanation of the columns 1541=head3 Explanation of the columns
1347 1542
1348I<sockets> is the number of sockets, and twice the number of "servers" (as 1543I<sockets> is the number of sockets, and twice the number of "servers" (as
1349each server has a read and write socket end). 1544each server has a read and write socket end).
1350 1545
1351I<create> is the time it takes to create a socketpair (which is 1546I<create> is the time it takes to create a socket pair (which is
1352nontrivial) and two watchers: an I/O watcher and a timeout watcher. 1547nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1353 1548
1354I<request>, the most important value, is the time it takes to handle a 1549I<request>, the most important value, is the time it takes to handle a
1355single "request", that is, reading the token from the pipe and forwarding 1550single "request", that is, reading the token from the pipe and forwarding
1356it to another server. This includes deleting the old timeout and creating 1551it to another server. This includes deleting the old timeout and creating
1429speed most when you have lots of watchers, not when you only have a few of 1624speed most when you have lots of watchers, not when you only have a few of
1430them). 1625them).
1431 1626
1432EV is again fastest. 1627EV is again fastest.
1433 1628
1434Perl again comes second. It is noticably faster than the C-based event 1629Perl again comes second. It is noticeably faster than the C-based event
1435loops Event and Glib, although the difference is too small to really 1630loops Event and Glib, although the difference is too small to really
1436matter. 1631matter.
1437 1632
1438POE also performs much better in this case, but is is still far behind the 1633POE also performs much better in this case, but is is still far behind the
1439others. 1634others.
1468specified in the variable. 1663specified in the variable.
1469 1664
1470You can make AnyEvent completely ignore this variable by deleting it 1665You can make AnyEvent completely ignore this variable by deleting it
1471before the first watcher gets created, e.g. with a C<BEGIN> block: 1666before the first watcher gets created, e.g. with a C<BEGIN> block:
1472 1667
1473 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } 1668 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1474 1669
1475 use AnyEvent; 1670 use AnyEvent;
1476 1671
1477Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 1672Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1478be used to probe what backend is used and gain other information (which is 1673be used to probe what backend is used and gain other information (which is
1479probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1674probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1480 1675
1481 1676
1482=head1 SEE ALSO 1677=head1 SEE ALSO
1678
1679Utility functions: L<AnyEvent::Util>.
1483 1680
1484Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 1681Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1485L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 1682L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1486 1683
1487Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 1684Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1488L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 1685L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1489L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 1686L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1490L<AnyEvent::Impl::POE>. 1687L<AnyEvent::Impl::POE>.
1491 1688
1689Non-blocking file handles, sockets, TCP clients and
1690servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
1691
1692Asynchronous DNS: L<AnyEvent::DNS>.
1693
1492Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 1694Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1493 1695
1494Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. 1696Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1495 1697
1496 1698
1497=head1 AUTHOR 1699=head1 AUTHOR
1498 1700
1499 Marc Lehmann <schmorp@schmorp.de> 1701 Marc Lehmann <schmorp@schmorp.de>
1500 http://home.schmorp.de/ 1702 http://home.schmorp.de/
1501 1703
1502=cut 1704=cut
1503 1705
15041 17061
1505 1707

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines