[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.102 by root, Sun Apr 27 21:16:26 2008 UTC vs.
Revision 1.125 by root, Fri May 23 23:37:13 2008 UTC

…		…
1	=head1 NAME	1	=head1 => NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, 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
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	26	nowadays. So what is different about AnyEvent?
…		…
78	The interface itself is vaguely similar, but not identical to the L<Event>	78	The interface itself is vaguely similar, but not identical to the L<Event>
79	module.	79	module.
80		80
81	During the first call of any watcher-creation method, the module tries	81	During the first call of any watcher-creation method, the module tries
82	to detect the currently loaded event loop by probing whether one of the	82	to detect the currently loaded event loop by probing whether one of the
83	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	83	following modules is already loaded: L<EV>,
84	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	84	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
85	L<POE>. The first one found is used. If none are found, the module tries	85	L<POE>. The first one found is used. If none are found, the module tries
86	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	86	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
87	adaptor should always succeed) in the order given. The first one that can	87	adaptor should always succeed) in the order given. The first one that can
88	be successfully loaded will be used. If, after this, still none could be	88	be successfully loaded will be used. If, after this, still none could be
…		…
279		279
280	Example: fork a process and wait for it	280	Example: 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
		300	If you are familiar with some event loops you will know that all of them
		301	require you to run some blocking "loop", "run" or similar function that
		302	will actively watch for new events and call your callbacks.
		303
		304	AnyEvent is different, it expects somebody else to run the event loop and
		305	will only block when necessary (usually when told by the user).
		306
		307	The instrument to do that is called a "condition variable", so called
		308	because they represent a condition that must become true.
		309
302	Condition variables can be created by calling the C<< AnyEvent->condvar >>	310	Condition variables can be created by calling the C<< AnyEvent->condvar
303	method without any arguments.	311	>> method, usually without arguments. The only argument pair allowed is
		312	C<cb>, which specifies a callback to be called when the condition variable
		313	becomes true.
304		314
305	A condition variable waits for a condition - precisely that the C<<	315	After creation, the conditon variable is "false" until it becomes "true"
306	->broadcast >> method has been called.	316	by calling the C<send> method.
307		317
308	They are very useful to signal that a condition has been fulfilled, for	318	Condition variables are similar to callbacks, except that you can
		319	optionally wait for them. They can also be called merge points - points
		320	in time where multiple outstandign events have been processed. And yet
		321	another way to call them is transations - each condition variable can be
		322	used to represent a transaction, which finishes at some point and delivers
		323	a result.
		324
		325	Condition variables are very useful to signal that something has finished,
309	example, if you write a module that does asynchronous http requests,	326	for example, if you write a module that does asynchronous http requests,
310	then a condition variable would be the ideal candidate to signal the	327	then a condition variable would be the ideal candidate to signal the
311	availability of results.	328	availability of results. The user can either act when the callback is
		329	called or can synchronously C<< ->recv >> for the results.
312		330
313	You can also use condition variables to block your main program until	331	You can also use them to simulate traditional event loops - for example,
314	an event occurs - for example, you could C<< ->wait >> in your main	332	you can block your main program until an event occurs - for example, you
315	program until the user clicks the Quit button in your app, which would C<<	333	could C<< ->recv >> in your main program until the user clicks the Quit
316	->broadcast >> the "quit" event.	334	button of your app, which would C<< ->send >> the "quit" event.
317		335
318	Note that condition variables recurse into the event loop - if you have	336	Note that condition variables recurse into the event loop - if you have
319	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you	337	two pieces of code that call C<< ->recv >> in a round-robbin fashion, you
320	lose. Therefore, condition variables are good to export to your caller, but	338	lose. Therefore, condition variables are good to export to your caller, but
321	you should avoid making a blocking wait yourself, at least in callbacks,	339	you should avoid making a blocking wait yourself, at least in callbacks,
322	as this asks for trouble.	340	as this asks for trouble.
323		341
324	This object has two methods:	342	Condition variables are represented by hash refs in perl, and the keys
		343	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
		344	easy (it is often useful to build your own transaction class on top of
		345	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
		346	it's C<new> method in your own C<new> method.
		347
		348	There are two "sides" to a condition variable - the "producer side" which
		349	eventually calls C<< -> send >>, and the "consumer side", which waits
		350	for the send to occur.
		351
		352	Example:
		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
		372	These methods should only be used by the producing side, i.e. the
		373	code/module that eventually sends the signal. Note that it is also
		374	the producer side which creates the condvar in most cases, but it isn't
		375	uncommon for the consumer to create it as well.
325		376
326	=over 4	377	=over 4
327		378
		379	=item $cv->send (...)
		380
		381	Flag the condition as ready - a running C<< ->recv >> and all further
		382	calls to C<recv> will (eventually) return after this method has been
		383	called. If nobody is waiting the send will be remembered.
		384
		385	If a callback has been set on the condition variable, it is called
		386	immediately from within send.
		387
		388	Any arguments passed to the C<send> call will be returned by all
		389	future C<< ->recv >> calls.
		390
		391	=item $cv->croak ($error)
		392
		393	Similar to send, but causes all call's to C<< ->recv >> to invoke
		394	C<Carp::croak> with the given error message/object/scalar.
		395
		396	This can be used to signal any errors to the condition variable
		397	user/consumer.
		398
		399	=item $cv->begin ([group callback])
		400
328	=item $cv->wait	401	=item $cv->end
329		402
330	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	403	These two methods are EXPERIMENTAL and MIGHT CHANGE.
		404
		405	These two methods can be used to combine many transactions/events into
		406	one. For example, a function that pings many hosts in parallel might want
		407	to use a condition variable for the whole process.
		408
		409	Every call to C<< ->begin >> will increment a counter, and every call to
		410	C<< ->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
		412	is I<supposed> to call C<< ->send >>, but that is not required. If no
		413	callback was set, C<send> will be called without any arguments.
		414
		415	Let'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
		432	This code fragment supposedly pings a number of hosts and calls
		433	C<send> after results for all then have have been gathered - in any
		434	order. To achieve this, the code issues a call to C<begin> when it starts
		435	each ping request and calls C<end> when it has received some result for
		436	it. Since C<begin> and C<end> only maintain a counter, the order in which
		437	results arrive is not relevant.
		438
		439	There is an additional bracketing call to C<begin> and C<end> outside the
		440	loop, which serves two important purposes: first, it sets the callback
		441	to be called once the counter reaches C<0>, and second, it ensures that
		442	C<send> is called even when C<no> hosts are being pinged (the loop
		443	doesn't execute once).
		444
		445	This is the general pattern when you "fan out" into multiple subrequests:
		446	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
		447	is called at least once, and then, for each subrequest you start, call
		448	C<begin> and for eahc subrequest you finish, call C<end>.
		449
		450	=back
		451
		452	=head3 METHODS FOR CONSUMERS
		453
		454	These methods should only be used by the consuming side, i.e. the
		455	code awaits the condition.
		456
		457	=over 4
		458
		459	=item $cv->recv
		460
		461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
331	called on c<$cv>, while servicing other watchers normally.	462	>> methods have been called on c<$cv>, while servicing other watchers
		463	normally.
332		464
333	You can only wait once on a condition - additional calls will return	465	You can only wait once on a condition - additional calls are valid but
334	immediately.	466	will return immediately.
		467
		468	If an error condition has been set by calling C<< ->croak >>, then this
		469	function will call C<croak>.
		470
		471	In list context, all parameters passed to C<send> will be returned,
		472	in scalar context only the first one will be returned.
335		473
336	Not all event models support a blocking wait - some die in that case	474	Not 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
338	using this from a module, never require a blocking wait>, but let the	476	using this from a module, never require a blocking wait>, but let the
339	caller decide whether the call will block or not (for example, by coupling	477	caller decide whether the call will block or not (for example, by coupling
340	condition variables with some kind of request results and supporting	478	condition variables with some kind of request results and supporting
341	callbacks so the caller knows that getting the result will not block,	479	callbacks so the caller knows that getting the result will not block,
342	while still suppporting blocking waits if the caller so desires).	480	while still suppporting blocking waits if the caller so desires).
343		481
344	Another reason I<never> to C<< ->wait >> in a module is that you cannot	482	Another reason I<never> to C<< ->recv >> in a module is that you cannot
345	sensibly have two C<< ->wait >>'s in parallel, as that would require	483	sensibly have two C<< ->recv >>'s in parallel, as that would require
346	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
347	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	485	can supply.
348	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
349	from different coroutines, however).
350		486
351	=item $cv->broadcast	487	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		488	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		489	versions and also integrates coroutines into AnyEvent, making blocking
		490	C<< ->recv >> calls perfectly safe as long as they are done from another
		491	coroutine (one that doesn't run the event loop).
352		492
353	Flag the condition as ready - a running C<< ->wait >> and all further	493	You can ensure that C<< -recv >> never blocks by setting a callback and
354	calls to C<wait> will (eventually) return after this method has been	494	only calling C<< ->recv >> from within that callback (or at a later
355	called. If nobody is waiting the broadcast will be remembered..	495	time). This will work even when the event loop does not support blocking
		496	waits otherwise.
		497
		498	=item $bool = $cv->ready
		499
		500	Returns true when the condition is "true", i.e. whether C<send> or
		501	C<croak> have been called.
		502
		503	=item $cb = $cv->cb ([new callback])
		504
		505	This is a mutator function that returns the callback set and optionally
		506	replaces it before doing so.
		507
		508	The callback will be called when the condition becomes "true", i.e. when
		509	C<send> or C<croak> are called. Calling C<recv> inside the callback
		510	or at any later time is guaranteed not to block.
356		511
357	=back	512	=back
358
359	Example:
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	$result_ready->wait;
376		513
377	=head1 GLOBAL VARIABLES AND FUNCTIONS	514	=head1 GLOBAL VARIABLES AND FUNCTIONS
378		515
379	=over 4	516	=over 4
380		517
…		…
386	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	523	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
387	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	524	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
388		525
389	The known classes so far are:	526	The known classes so far are:
390		527
391	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
392	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
393	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	528	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
394	AnyEvent::Impl::Event based on Event, second best choice.	529	AnyEvent::Impl::Event based on Event, second best choice.
		530	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
395	AnyEvent::Impl::Glib based on Glib, third-best choice.	531	AnyEvent::Impl::Glib based on Glib, third-best choice.
396	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
397	AnyEvent::Impl::Tk based on Tk, very bad choice.	532	AnyEvent::Impl::Tk based on Tk, very bad choice.
398	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	533	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
399	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	534	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
400	AnyEvent::Impl::POE based on POE, not generic enough for full support.	535	AnyEvent::Impl::POE based on POE, not generic enough for full support.
401		536
…		…
414	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	549	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
415	if necessary. You should only call this function right before you would	550	if necessary. You should only call this function right before you would
416	have created an AnyEvent watcher anyway, that is, as late as possible at	551	have created an AnyEvent watcher anyway, that is, as late as possible at
417	runtime.	552	runtime.
418		553
		554	=item $guard = AnyEvent::post_detect { BLOCK }
		555
		556	Arranges for the code block to be executed as soon as the event model is
		557	autodetected (or immediately if this has already happened).
		558
		559	If called in scalar or list context, then it creates and returns an object
		560	that automatically removes the callback again when it is destroyed. See
		561	L<Coro::BDB> for a case where this is useful.
		562
		563	=item @AnyEvent::post_detect
		564
		565	If there are any code references in this array (you can C<push> to it
		566	before or after loading AnyEvent), then they will called directly after
		567	the event loop has been chosen.
		568
		569	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		570	if it contains a true value then the event loop has already been detected,
		571	and the array will be ignored.
		572
		573	Best 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
423	As a module author, you should C<use AnyEvent> and call AnyEvent methods	579	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
426	Be careful when you create watchers in the module body - AnyEvent will	582	Be careful when you create watchers in the module body - AnyEvent will
427	decide which event module to use as soon as the first method is called, so	583	decide which event module to use as soon as the first method is called, so
428	by calling AnyEvent in your module body you force the user of your module	584	by calling AnyEvent in your module body you force the user of your module
429	to load the event module first.	585	to load the event module first.
430		586
431	Never call C<< ->wait >> on a condition variable unless you I<know> that	587	Never call C<< ->recv >> on a condition variable unless you I<know> that
432	the C<< ->broadcast >> method has been called on it already. This is	588	the C<< ->send >> method has been called on it already. This is
433	because it will stall the whole program, and the whole point of using	589	because it will stall the whole program, and the whole point of using
434	events is to stay interactive.	590	events is to stay interactive.
435		591
436	It is fine, however, to call C<< ->wait >> when the user of your module	592	It is fine, however, to call C<< ->recv >> when the user of your module
437	requests it (i.e. if you create a http request object ad have a method	593	requests it (i.e. if you create a http request object ad have a method
438	called C<results> that returns the results, it should call C<< ->wait >>	594	called C<results> that returns the results, it should call C<< ->recv >>
439	freely, as the user of your module knows what she is doing. always).	595	freely, 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
443	There will always be a single main program - the only place that should	599	There will always be a single main program - the only place that should
…		…
477		633
478	Provide read and write buffers and manages watchers for reads and writes.	634	Provide read and write buffers and manages watchers for reads and writes.
479		635
480	=item L<AnyEvent::Socket>	636	=item L<AnyEvent::Socket>
481		637
482	Provides a means to do non-blocking connects, accepts etc.	638	Provides various utility functions for (internet protocol) sockets,
		639	addresses and name resolution. Also functions to create non-blocking tcp
		640	connections or tcp servers, with IPv6 and SRV record support and more.
483		641
484	=item L<AnyEvent::HTTPD>	642	=item L<AnyEvent::HTTPD>
485		643
486	Provides a simple web application server framework.	644	Provides a simple web application server framework.
487		645
488	=item L<AnyEvent::DNS>	646	=item L<AnyEvent::DNS>
489		647
490	Provides asynchronous DNS resolver capabilities, beyond what	648	Provides rich asynchronous DNS resolver capabilities.
491	L<AnyEvent::Util> offers.
492		649
493	=item L<AnyEvent::FastPing>	650	=item L<AnyEvent::FastPing>
494		651
495	The fastest ping in the west.	652	The fastest ping in the west.
496		653
…		…
511		668
512	High level API for event-based execution flow control.	669	High level API for event-based execution flow control.
513		670
514	=item L<Coro>	671	=item L<Coro>
515		672
516	Has special support for AnyEvent.	673	Has special support for AnyEvent via L<Coro::AnyEvent>.
		674
		675	=item L<AnyEvent::AIO>, L<IO::AIO>
		676
		677	Truly asynchronous I/O, should be in the toolbox of every event
		678	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		679	together.
		680
		681	=item L<AnyEvent::BDB>, L<BDB>
		682
		683	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
		684	IO::AIO and AnyEvent together.
517		685
518	=item L<IO::Lambda>	686	=item L<IO::Lambda>
519		687
520	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	688	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
521
522	=item L<IO::AIO>
523
524	Truly asynchronous I/O, should be in the toolbox of every event
525	programmer. Can be trivially made to use AnyEvent.
526
527	=item L<BDB>
528
529	Truly asynchronous Berkeley DB access. Can be trivially made to use
530	AnyEvent.
531		689
532	=back	690	=back
533		691
534	=cut	692	=cut
535		693
…		…
538	no warnings;	696	no warnings;
539	use strict;	697	use strict;
540		698
541	use Carp;	699	use Carp;
542		700
543	our $VERSION = '3.3';	701	our $VERSION = '3.6';
544	our $MODEL;	702	our $MODEL;
545		703
546	our $AUTOLOAD;	704	our $AUTOLOAD;
547	our @ISA;	705	our @ISA;
548		706
549	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	707	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
550		708
551	our @REGISTRY;	709	our @REGISTRY;
552		710
553	my @models = (	711	my @models = (
554	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
555	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
556	[EV:: => AnyEvent::Impl::EV::],	712	[EV:: => AnyEvent::Impl::EV::],
557	[Event:: => AnyEvent::Impl::Event::],	713	[Event:: => AnyEvent::Impl::Event::],
558	[Glib:: => AnyEvent::Impl::Glib::],
559	[Tk:: => AnyEvent::Impl::Tk::],	714	[Tk:: => AnyEvent::Impl::Tk::],
560	[Wx:: => AnyEvent::Impl::POE::],	715	[Wx:: => AnyEvent::Impl::POE::],
561	[Prima:: => AnyEvent::Impl::POE::],	716	[Prima:: => AnyEvent::Impl::POE::],
562	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	717	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
563	# everything below here will not be autoprobed as the pureperl backend should work everywhere	718	# everything below here will not be autoprobed as the pureperl backend should work everywhere
		719	[Glib:: => AnyEvent::Impl::Glib::],
564	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	720	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
565	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	721	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
566	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	722	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
567	);	723	);
568		724
569	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	725	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
		726
		727	our @post_detect;
		728
		729	sub post_detect(&) {
		730	my ($cb) = @_;
		731
		732	if ($MODEL) {
		733	$cb->();
		734
		735	1
		736	} else {
		737	push @post_detect, $cb;
		738
		739	defined wantarray
		740	? bless \$cb, "AnyEvent::Util::PostDetect"
		741	: ()
		742	}
		743	}
		744
		745	sub AnyEvent::Util::PostDetect::DESTROY {
		746	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		747	}
570		748
571	sub detect() {	749	sub detect() {
572	unless ($MODEL) {	750	unless ($MODEL) {
573	no strict 'refs';	751	no strict 'refs';
574		752
…		…
608	last;	786	last;
609	}	787	}
610	}	788	}
611		789
612	$MODEL	790	$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.";	791	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
614	}	792	}
615	}	793	}
616		794
617	unshift @ISA, $MODEL;	795	unshift @ISA, $MODEL;
618	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	796	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		797
		798	(shift @post_detect)->() while @post_detect;
619	}	799	}
620		800
621	$MODEL	801	$MODEL
622	}	802	}
623		803
…		…
633	$class->$func (@_);	813	$class->$func (@_);
634	}	814	}
635		815
636	package AnyEvent::Base;	816	package AnyEvent::Base;
637		817
638	# default implementation for ->condvar, ->wait, ->broadcast	818	# default implementation for ->condvar
639		819
640	sub condvar {	820	sub condvar {
641	bless \my $flag, "AnyEvent::Base::CondVar"	821	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
642	}
643
644	sub AnyEvent::Base::CondVar::broadcast {
645	${$_[0]}++;
646	}
647
648	sub AnyEvent::Base::CondVar::wait {
649	AnyEvent->one_event while !${$_[0]};
650	}	822	}
651		823
652	# default implementation for ->signal	824	# default implementation for ->signal
653		825
654	our %SIG_CB;	826	our %SIG_CB;
…		…
728	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	900	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
729		901
730	undef $CHLD_W unless keys %PID_CB;	902	undef $CHLD_W unless keys %PID_CB;
731	}	903	}
732		904
		905	package AnyEvent::CondVar;
		906
		907	our @ISA = AnyEvent::CondVar::Base::;
		908
		909	package AnyEvent::CondVar::Base;
		910
		911	sub _send {
		912	# nop
		913	}
		914
		915	sub send {
		916	my $cv = shift;
		917	$cv->{_ae_sent} = [@_];
		918	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		919	$cv->_send;
		920	}
		921
		922	sub croak {
		923	$_[0]{_ae_croak} = $_[1];
		924	$_[0]->send;
		925	}
		926
		927	sub ready {
		928	$_[0]{_ae_sent}
		929	}
		930
		931	sub _wait {
		932	AnyEvent->one_event while !$_[0]{_ae_sent};
		933	}
		934
		935	sub recv {
		936	$_[0]->_wait;
		937
		938	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		939	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		940	}
		941
		942	sub cb {
		943	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		944	$_[0]{_ae_cb}
		945	}
		946
		947	sub begin {
		948	++$_[0]{_ae_counter};
		949	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		950	}
		951
		952	sub end {
		953	return if --$_[0]{_ae_counter};
		954	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		955	}
		956
		957	# undocumented/compatibility with pre-3.4
		958	*broadcast = \&send;
		959	*wait = \&_wait;
		960
733	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	961	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
734		962
735	This is an advanced topic that you do not normally need to use AnyEvent in	963	This is an advanced topic that you do not normally need to use AnyEvent in
736	a module. This section is only of use to event loop authors who want to	964	a module. This section is only of use to event loop authors who want to
737	provide AnyEvent compatibility.	965	provide AnyEvent compatibility.
…		…
805		1033
806	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1034	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
807	could start your program like this:	1035	could start your program like this:
808		1036
809	PERL_ANYEVENT_MODEL=Perl perl ...	1037	PERL_ANYEVENT_MODEL=Perl perl ...
		1038
		1039	=item C<PERL_ANYEVENT_PROTOCOLS>
		1040
		1041	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1042	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1043	of autoprobing).
		1044
		1045	Must be set to a comma-separated list of protocols or address families,
		1046	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1047	used, and preference will be given to protocols mentioned earlier in the
		1048	list.
		1049
		1050	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1051	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1052	- only support IPv4, never try to resolve or contact IPv6
		1053	addressses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1054	IPv6, but prefer IPv6 over IPv4.
810		1055
811	=back	1056	=back
812		1057
813	=head1 EXAMPLE PROGRAM	1058	=head1 EXAMPLE PROGRAM
814		1059
…		…
825	poll => 'r',	1070	poll => 'r',
826	cb => sub {	1071	cb => sub {
827	warn "io event <$_[0]>\n"; # will always output <r>	1072	warn "io event <$_[0]>\n"; # will always output <r>
828	chomp (my $input = <STDIN>); # read a line	1073	chomp (my $input = <STDIN>); # read a line
829	warn "read: $input\n"; # output what has been read	1074	warn "read: $input\n"; # output what has been read
830	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1075	$cv->send if $input =~ /^q/i; # quit program if /^q/i
831	},	1076	},
832	);	1077	);
833		1078
834	my $time_watcher; # can only be used once	1079	my $time_watcher; # can only be used once
835		1080
…		…
840	});	1085	});
841	}	1086	}
842		1087
843	new_timer; # create first timer	1088	new_timer; # create first timer
844		1089
845	$cv->wait; # wait until user enters /^q/i	1090	$cv->recv; # wait until user enters /^q/i
846		1091
847	=head1 REAL-WORLD EXAMPLE	1092	=head1 REAL-WORLD EXAMPLE
848		1093
849	Consider the L<Net::FCP> module. It features (among others) the following	1094	Consider the L<Net::FCP> module. It features (among others) the following
850	API calls, which are to freenet what HTTP GET requests are to http:	1095	API calls, which are to freenet what HTTP GET requests are to http:
…		…
906		1151
907	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1152	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
908		1153
909	if (end-of-file or data complete) {	1154	if (end-of-file or data complete) {
910	$txn->{result} = $txn->{buf};	1155	$txn->{result} = $txn->{buf};
911	$txn->{finished}->broadcast;	1156	$txn->{finished}->send;
912	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1157	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
913	}	1158	}
914		1159
915	The C<result> method, finally, just waits for the finished signal (if the	1160	The C<result> method, finally, just waits for the finished signal (if the
916	request was already finished, it doesn't wait, of course, and returns the	1161	request was already finished, it doesn't wait, of course, and returns the
917	data:	1162	data:
918		1163
919	$txn->{finished}->wait;	1164	$txn->{finished}->recv;
920	return $txn->{result};	1165	return $txn->{result};
921		1166
922	The actual code goes further and collects all errors (C<die>s, exceptions)	1167	The actual code goes further and collects all errors (C<die>s, exceptions)
923	that occured during request processing. The C<result> method detects	1168	that occured during request processing. The C<result> method detects
924	whether an exception as thrown (it is stored inside the $txn object)	1169	whether an exception as thrown (it is stored inside the $txn object)
…		…
959		1204
960	my $quit = AnyEvent->condvar;	1205	my $quit = AnyEvent->condvar;
961		1206
962	$fcp->txn_client_get ($url)->cb (sub {	1207	$fcp->txn_client_get ($url)->cb (sub {
963	...	1208	...
964	$quit->broadcast;	1209	$quit->send;
965	});	1210	});
966		1211
967	$quit->wait;	1212	$quit->recv;
968		1213
969		1214
970	=head1 BENCHMARKS	1215	=head1 BENCHMARKS
971		1216
972	To give you an idea of the performance and overheads that AnyEvent adds	1217	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1001	all watchers, to avoid adding memory overhead. That means closure creation	1246	all watchers, to avoid adding memory overhead. That means closure creation
1002	and memory usage is not included in the figures.	1247	and memory usage is not included in the figures.
1003		1248
1004	I<invoke> is the time, in microseconds, used to invoke a simple	1249	I<invoke> is the time, in microseconds, used to invoke a simple
1005	callback. The callback simply counts down a Perl variable and after it was	1250	callback. The callback simply counts down a Perl variable and after it was
1006	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1251	invoked "watcher" times, it would C<< ->send >> a condvar once to
1007	signal the end of this phase.	1252	signal the end of this phase.
1008		1253
1009	I<destroy> is the time, in microseconds, that it takes to destroy a single	1254	I<destroy> is the time, in microseconds, that it takes to destroy a single
1010	watcher.	1255	watcher.
1011		1256
…		…
1071	file descriptor is dup()ed for each watcher. This shows that the dup()	1316	file descriptor is dup()ed for each watcher. This shows that the dup()
1072	employed by some adaptors is not a big performance issue (it does incur a	1317	employed by some adaptors is not a big performance issue (it does incur a
1073	hidden memory cost inside the kernel which is not reflected in the figures	1318	hidden memory cost inside the kernel which is not reflected in the figures
1074	above).	1319	above).
1075		1320
1076	C<POE>, regardless of underlying event loop (whether using its pure	1321	C<POE>, regardless of underlying event loop (whether using its pure perl
1077	perl select-based backend or the Event module, the POE-EV backend	1322	select-based backend or the Event module, the POE-EV backend couldn't
1078	couldn't be tested because it wasn't working) shows abysmal performance	1323	be tested because it wasn't working) shows abysmal performance and
1079	and memory usage: Watchers use almost 30 times as much memory as	1324	memory usage with AnyEvent: Watchers use almost 30 times as much memory
1080	EV watchers, and 10 times as much memory as Event (the high memory	1325	as EV watchers, and 10 times as much memory as Event (the high memory
1081	requirements are caused by requiring a session for each watcher). Watcher	1326	requirements are caused by requiring a session for each watcher). Watcher
1082	invocation speed is almost 900 times slower than with AnyEvent's pure perl	1327	invocation speed is almost 900 times slower than with AnyEvent's pure perl
		1328	implementation.
		1329
1083	implementation. The design of the POE adaptor class in AnyEvent can not	1330	The design of the POE adaptor class in AnyEvent can not really account
1084	really account for this, as session creation overhead is small compared	1331	for the performance issues, though, as session creation overhead is
1085	to execution of the state machine, which is coded pretty optimally within	1332	small compared to execution of the state machine, which is coded pretty
1086	L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.	1333	optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that
		1334	using multiple sessions is not a good approach, especially regarding
		1335	memory usage, even the author of POE could not come up with a faster
		1336	design).
1087		1337
1088	=head3 Summary	1338	=head3 Summary
1089		1339
1090	=over 4	1340	=over 4
1091		1341
…		…
1170		1420
1171	=head3 Summary	1421	=head3 Summary
1172		1422
1173	=over 4	1423	=over 4
1174		1424
1175	=item * The pure perl implementation performs extremely well, considering	1425	=item * The pure perl implementation performs extremely well.
1176	that it uses select.
1177		1426
1178	=item * Avoid Glib or POE in large projects where performance matters.	1427	=item * Avoid Glib or POE in large projects where performance matters.
1179		1428
1180	=back	1429	=back
1181		1430
…		…
1230		1479
1231		1480
1232	=head1 FORK	1481	=head1 FORK
1233		1482
1234	Most event libraries are not fork-safe. The ones who are usually are	1483	Most event libraries are not fork-safe. The ones who are usually are
1235	because they are so inefficient. Only L<EV> is fully fork-aware.	1484	because they rely on inefficient but fork-safe C<select> or C<poll>
		1485	calls. Only L<EV> is fully fork-aware.
1236		1486
1237	If you have to fork, you must either do so I<before> creating your first	1487	If you have to fork, you must either do so I<before> creating your first
1238	watcher OR you must not use AnyEvent at all in the child.	1488	watcher OR you must not use AnyEvent at all in the child.
1239		1489
1240		1490
…		…
1252		1502
1253	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1503	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1254		1504
1255	use AnyEvent;	1505	use AnyEvent;
1256		1506
		1507	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1508	be used to probe what backend is used and gain other information (which is
		1509	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1510
1257		1511
1258	=head1 SEE ALSO	1512	=head1 SEE ALSO
1259		1513
1260	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1514	Utility functions: L<AnyEvent::Util>.
1261	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1515
		1516	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1262	L<Event::Lib>, L<Qt>, L<POE>.	1517	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1263		1518
1264	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1519	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1265	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1520	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1266	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1521	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1267	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1522	L<AnyEvent::Impl::POE>.
1268		1523
		1524	Non-blocking file handles, sockets, TCP clients and
		1525	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1526
		1527	Asynchronous DNS: L<AnyEvent::DNS>.
		1528
		1529	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1530
1269	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1531	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1270		1532
1271		1533
1272	=head1 AUTHOR	1534	=head1 AUTHOR
1273		1535
1274	Marc Lehmann <schmorp@schmorp.de>	1536	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.102 by root, Sun Apr 27 21:16:26 2008 UTC vs. Revision 1.125 by root, Fri May 23 23:37:13 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.102 by root, Sun Apr 27 21:16:26 2008 UTC vs.
Revision 1.125 by root, Fri May 23 23:37:13 2008 UTC